No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Energy Consumption of Asphalt and Reinforced Concrete Pavement Materials and Construction
Abstract
In addition to traditional economic and technical objectives, environmental impact, and sustainability are increasingly being considered in the design of roadways and other infrastructure projects. This paper presents an abbreviated life cycle inventory assessment of a continuously reinforced concrete pavement (CRCP) and an asphalt pavement with respect to the energy consumed by each pavement type for the construction of a roadway. For CRCP, energy is primarily consumed during the manufacture of cement and reinforcing steel, which together account for approximately 94% of the total amount of energy consumed from extraction of raw materials through placement of the CRCP. For asphalt pavement, the major consumption of energy from extraction through placement occurs during asphalt mixing and drying of aggregates (48%) and the production of bitumen (40%). The assessment results highlight where sustainable design efforts to reduce energy consumption can best be directed in the initial phases of a pavement's life cycle.
... A cement -így a beton -gyártása rendkívül nagy energia-igényű folyamat. A következő 6. ábra bekeretezett része a beton gyártásának folyamatábráját és életének folyamatait mutatja be az [25] [26] [27] irodalmak alapján. 6. ábra: Betonkeverék előállítása és életének folyamata. ...
... A nedves eljárásnál az üzemi építési költségek meglehetősen alacsonyak és a kiváló minőségű termékeket egyszerűen gyártják. A száraz eljárásnál kevesebb az energiafogyasztás és a működési költségek alacsonyabbak [25], [29]. A Zapata et al. tanulmánya alapján [25] a portlandcement-beton (PCC) előállításának energiafelhasználása -azaz a cement, adalékanyag, a víz és adalékanyagok szállítása, keverése -lényegesen kevesebb, mint maga a cement előállításának energiaigénye. ...
... A száraz eljárásnál kevesebb az energiafogyasztás és a működési költségek alacsonyabbak [25], [29]. A Zapata et al. tanulmánya alapján [25] a portlandcement-beton (PCC) előállításának energiafelhasználása -azaz a cement, adalékanyag, a víz és adalékanyagok szállítása, keverése -lényegesen kevesebb, mint maga a cement előállításának energiaigénye. ...
Az építési folyamatok energiaigényének csökkentése egyaránt gazdasági és fenntarthatósági előnyökkel bír. A cikk célja az útpályaszerkezetek energiaigényének vizsgálata, annak eredményének bemutatása. Ehhez a cikk összegyűjtött szakirodalmak alapján meghatározta a különböző építési folyamatok energiaigényeit, valamint egy esettanulmányon keresztül összehasonlítja a magyar előírásoknak megfelelően (UME) mind aszfalt, mind betonburkolattal megtervezett autópályaszakasz energiaigényét, figyelembevéve a folyamatokat a nyersanyag kitermelésétől a pályaszerkezet építéséig. Az esettanulmány eredményeként látható, hogy a betonburkolatok energiaszükséglete közel 60%-kal nagyobb, mint az aszfaltburkolatoké. Ennek oka a portlandcement gyártásának kimagaslóan magas energiaigénye, melyet az egyéb építési folyamatok nem tudtak árnyalni.
... Pavements based on asphalt mixtures are estimated to be 70% less energy and emission-intensive than concretebased pavements based on a life cycle analysis [21]. However, if the calculation of the energy and carbon inventory is done per value of generated products (output), asphalt production becomes the second most energy and carbon-intensive production process [22]. There are several opportunities to reduce the energy and carbon intensity of asphalt pavements by using warmly-mixed instead of hot-mixed materials, mixing the asphalt with recycled materials such as rubber, plastics, or used asphalt, and reducing the moisture content of asphalt [21]. ...
... There are several opportunities to reduce the energy and carbon intensity of asphalt pavements by using warmly-mixed instead of hot-mixed materials, mixing the asphalt with recycled materials such as rubber, plastics, or used asphalt, and reducing the moisture content of asphalt [21]. This emanates from the understanding that, in the case of asphalt, 88% of energy consumption is related to the preparation of gravels, bitumen, and mixing of asphalt [22]. The construction and use phases of pavements are associated with environmental sustainability concerns related to energy and carbon emissions during materials transportation and handling, road and pathway preparation, excavation, and finishing, as well as ground-level air pollution (release of bitumen particles and particulate matters into the air in case of asphalt), traffic congestion (more frequent in case of asphalt due to faster degradation) [22][23]. ...
... This emanates from the understanding that, in the case of asphalt, 88% of energy consumption is related to the preparation of gravels, bitumen, and mixing of asphalt [22]. The construction and use phases of pavements are associated with environmental sustainability concerns related to energy and carbon emissions during materials transportation and handling, road and pathway preparation, excavation, and finishing, as well as ground-level air pollution (release of bitumen particles and particulate matters into the air in case of asphalt), traffic congestion (more frequent in case of asphalt due to faster degradation) [22][23]. ...
Global initiatives to improve environmental sustainability have centered on reducing energy consumption and developing technological solutions for greener power generation. Current insights on innovations for environmental sustainability are primarily from developed countries, with limited studies originating from developing countries. This study focuses on solar paver technology, a potential innovation for sustainable generation of power. The interest in this technology lies in its dual-purpose ability to enable both functional road surfaces and the use of solar roadways that can generate electricity to power other road infrastructure such as electric lights. To maximize the potential of success of deployment of solar pavers, it is important to investigate the practicalities of solar pavers and understand the perceptions of stakeholders that will be responsible for the implementation of solar pavers. This research addresses this gap in knowledge. Thirty construction industry stakeholders in Malaysia were interviewed through focus group discussions and interviews. This study applied the diffusion of innovation theory to develop an understanding of the nuances of solar pavers. The findings identified three superordinate categories (motivation, opportunity, and ability) and nine categories (compliance with green initiatives, promote corporate social responsibility, dual functionality, financial incentives, sunny climate, increased environmental awareness, green experience, experts network and familiarity with solar technology) as the key enablers. Key barriers constitute two superordinate categories (challenges and weaknesses) and ten categories (reluctant authority, vandalism, complexity of installation and maintenance, high humidity and rainfall, negative environmental impact, high cost, design flaws, low efficiency, questionable practicality, and better comparative opportunities). There is an acceptance of solar pavers by the stakeholders and cost and ownership structures are the key to the deployment. The findings provide fresh insights into a new form of sustainable solar paver engendering new streams of research in construction engineering and technology management. Implications for management and organizational research are discussed.
... In the meanwhile, with 29.8%, 58.5%and 34.0%studies, the consideration of usage, M&R and EOL phases was less common [16]. [10], [9], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69] Input-output 8 (12.5%) [70], [71], [33], [72], [73], [18], [34], [74] Hybrid 11 (17.2%) [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85] Others (ANN, regression, etc.) 8 (12.5%) [86], [87], [88], [89], [90], [91], [1], [92] Total 64 (100%) [37], [77], [78], [79], [80], [47], [56], [57], [73], [10], [35], [76], [38], [82], [83], [52], [ [39], [45], [33], [81], [49], [84], [72], [86], [ [88], [91], [59], [64], [66], [1] -√ ---12 (18.8%) [50], [51], [53], [54], [58], [87], [89], [60], [63], [65], [68], [ ...
... [10], [9], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69] Input-output 8 (12.5%) [70], [71], [33], [72], [73], [18], [34], [74] Hybrid 11 (17.2%) [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85] Others (ANN, regression, etc.) 8 (12.5%) [86], [87], [88], [89], [90], [91], [1], [92] Total 64 (100%) [37], [77], [78], [79], [80], [47], [56], [57], [73], [10], [35], [76], [38], [82], [83], [52], [ [39], [45], [33], [81], [49], [84], [72], [86], [ [88], [91], [59], [64], [66], [1] -√ ---12 (18.8%) [50], [51], [53], [54], [58], [87], [89], [60], [63], [65], [68], [ ...
... [42], [44], [45], [33], [55], [72], [88], [85], [91], [64], [34], [66], [67], [1], [74] Rigid pavement (concrete) 8 (12.5%) [43], [46], [37], [81], [90], [59], [61], [18] Flexible and rigid pavement (both asphalt and concrete) 24 (37.5%) [10], [9], [70], [35], [36], [76], [39], [40], [41], [78], [79], [80], [82], [83], [47], [48], [49], [50], [84], [52], [56], [57], [73], [62] Others part of road pavement (earthwork, polyurethane, etc.) 15 (23.4%) [38], [77], [51], [53], [54], [86], [58], [87], [89], [60], [63], [65], [68], [69], [92] Total 64 (100%) ...
LCA has been utilized over the past two decades to estimate the environmental impacts of pavement in infrastructures. The purpose of this study is to systematically map research on the use of LCA to calculate energy and emissions in road infrastructure projects. The research method is carried out by a literature review, in terms of systematic mapping study of a number of previous scientific publications, in the form of documents that have been published in international and national journals and proceedings, etc., in the last thirty years. The results show that: The topic of LCA is still an interesting area of research, and the trend from year to year shows an increase in the publication of articles in reputable journals. As much as 57.8% research, using the process based calculation method. Only 15.6% of research calculated energy and emissions in the four completed stages of the project life cycle. As much as 37.5% research compared the flexible and rigid pavement as research objects. There is a chance to research the development of the energy optimization model for road infrastructure projects using cradle to cradle system boundary, from initiation to the end of life as a whole project life cycle.
... Zapata and Gambatese [6] compared the energy consumed during the construction of a continuously reinforced concrete pavement (CRCP) versus an asphalt pavement using an abbreviated life cycle inventory assessment. In CRCP, energy is primarily consumed during the manufacturing of cement and reinforcing steel, which together account for approximately 94% of the total amount of energy consumed from the extraction of raw materials to the placement of the CRCP. ...
... Such a pavement is composed of a jointed reinforced concrete slab, a cemented treated foundation layer (typical elastic modulus of 3000 MPa), and a subgrade that has been carefully prepared before the pavement's construction (typical elastic modulus of 120 MPa). When experimental data are not available, concrete properties can be derived from the 28-day cubic compressive strength (R ck ) by following the Italian construction standard [32] using Equations (4)-(8) for cylindrical compressive strength (f ck ), cubic mean compressive strength (f cm ), flexural axial strength (f ctm ), flexural tensile strength (f cfm ) and the elastic modulus (E cm ): f ck = 0.83 R ck (4) f cm = f ck + 8 (5) f cm = f ck + 8 (6) f cfm = 1.2f ctm (7) E cm = 22000( f cm/10) 0.3 (8) As an example, if the R ck is equal to 30 MPa, the f ck , f cm , f ctm , f cfm and E cm are 24.9 MPa, 32.9 MPa, 2.6 MPa, 3.1 MPa and 31,447 MPa, respectively. ...
Nowadays, roadway infrastructures are designed in order to satisfy technical and economical requirements, as well as to guarantee advanced environmental performance. Focusing on that, this paper deals with an innovative procedure for the characterization of pavement materials, both asphalt and cement-bound mixtures. The methodology takes its cue from a previous study in which the so-called Environmental Asphalt Rating (EAR) was firstly introduced as a reference parameter for asphalt pavements to evaluate technical offers and for the assignment of scores, in terms of environmental impacts, during the tender phase. In this work, the EAR methodology is revised with a focus on the main variations and improvements related to the new version of the ISO standard. By applying the same approach to rigid or concrete pavements, a preliminary version of the Environmental Concrete Rating (ECR) is presented. For ECR, a correction is provided regarding functionality through a fatigue-related parameter and the surface characteristics related to the IRI value. Despite its strong applicability to the pavement sector, the strength of the proposed method is its ability to be fine-tuned to different fields by varying the associated performance coefficients.
... Several studies have demonstrated that high-volume fly ash (HVFA) can be used as a substitution for Portland cement or a replacement in concrete pavement [25,33,36,46]. Naik et al. [35] reported that a conventional paving concrete mixture with 50 % Class C fly ash exhibited excellent strength and durability when it was used as a replacement for cement. ...
... Furthermore, before applying coal ash in pavement base stabilization, the relationship between a mixture's mechanical properties and its structural design parameters must be established. Coal ash used in the pavement base layer was either partially replaced cement by fly ash or aggregate with bottom ash [25,33,35,36,46]. No study has investigated the use of 100 % CACSM as a pavement base layer. ...
Coal fly ash (CFA) and coal bottom ash (CBA) are coal combustion's primary solid waste products. This solid waste management is a substantial challenge for power plants and local authorities. In order to apply coal ash as a pavement base material, the relationship of the mixture's mechanical properties with structural design parameters for pavement design and analysis must be explored. No study has investigated the mechanical behavior of the 100% coal ash cement stabilized material (CACSM) as a pavement base layer. Therefore, this study aimed to investigate the structural layer coefficient of CACSM used in the American Association of State Highway and Transportation Officials (AASHTO) 1993 pavement design guide. The study consisted of laboratory material characterization and field evaluation. The mechanical property test revealed that CACSM has a self-healing ability; coal ash appeared to influence the secondary curing of the specimens significantly. Strength towards the ends of stage I and stage II showed the influence of high pozzolanic on the CACSM, which resulted in improved long-term performance. The layer coefficients of the locations in the field test ranged from 0.22 to 0.24. By contrast, for the granular base and cement-treated base, these values were 0.07 to 0.14 and 0.17-0.20, respectively. The study findings show that CACSM as a pavement base is a viable solution that can help develop transportation infrastructure with enhanced concrete durability and lower carbon footprint emissions.
... This enormous production consumes approximately 136x10 6 MWh energy per year (Androjić et al., 2020). Predominantly the energy required for the asphalt mixture production is consumed during heating the asphalt binder, drying the mineral aggregates, and mixing the mineral aggregates with the asphalt binder (Jullien et al., 2011;Zapata and Gambatese, 2005). Notably, 70-100 kWh per ton energy is required for the drying and heating process, whereas only 5-8 kWh is needed for the transportation and storage of asphalt mixtures (Androjić et al., 2020;EAPA, 2007). ...
... It should also be noted that the manufacturing and transportation of WMA additives may further release emissions and will require additional energy. As per previous literature (Jamshidi et al., 2013;Mazumder et al., 2016;Qin and Sun, 2022;Stimilli et al., 2017;Zapata and Gambatese, 2005;Zaumanis et al., 2012), the contribution from manufacturing and transportation of additives is negligible compared to the variation caused by the change in production temperatures and hence is neglected in this study. As different fuel types can be used in the mixing plant, its effect has been considered for performing the ELCA. ...
This paper assessed the impact of five different WMA additives categorized under organic, chemical and foaming-based technologies on the energy requirement and green house gas (GHG) emissions. The maximum bearable cost, corresponding to different additives, was determined to assess the optimal choice of warm mix technologies. Results demonstrated that the addition of WMA additives lowers the heat energy by 3-12% compared to HMA. Although diesel is the most expensive fuel (considered in this study), its use can offset the cost of additives, for some WMA additives, namely: SR0.7, C0.2, C0.35, and R0.4. Calculations indicated that among the various warm mix additives, Sasobit Redux produces least emissions, followed by Aspha-min, Rediset, Sasobit, Cecabase, and viscosity graded binder. It was concluded that the use of WMA technologies can provide possible cost savings, and reduction in GHG emissions.
... On the other hand, work zone costs arise from the presence of work zones during initial construction or maintenance activities [28]. Furthermore, previous research [29][30][31][32] has predominantly concentrated on comparing asphalt and concrete pavements, overlooking the crucial aspect of conducting systematic LCCA to investigate the economic implications of motorway rigid pavement alternatives, considering the availability of the construction method. Heidari's research [33] findings, considering LCCA, resulted in the selection of plain cement concrete pavement over asphalt concrete pavement. ...
Road infrastructure serves as a foundational driver of a nation’s economic and cultural growth. Incorporating life cycle cost analysis (LCCA), as well as considerations of availability and environmental impact, enables policymakers to make strategic decisions that not only enhance fiscal efficiency but also support sustainable progress. This paper centers on an in-depth examination of two prevalent pavement technologies: continuously reinforced concrete pavements (CRCP) and jointed plain concrete pavements (JPCP). It specifically delineates the application of these methods to a hypothetical one-kilometer motorway construction in Germany. Employing LCCA for concrete pavements, the paper evaluates long-term fiscal prudence among alternative investment opportunities, factoring in resource utilization—both materials and machinery—and long-term care and upkeep obligations over the pavements’ operational lifespans. The analysis extends to appraise agency expenditures associated with the pair of pavement strategies and estimates the concomitant delay durations and costs relevant to the exemplar project. Central to this research is the investigation of road availability and its quantifiable influence on traffic efficacy, parsing through metrics such as the tally of days roads are out of service and the subsequent repercussions on vehicular flow. The investigation also proposes strategies for the reduction of embodied carbon in CRCP and JPCP systems. While accounting for variances in functional performance and vehicular comfort levels, this study contributes scientifically by tackling pragmatic engineering dilemmas involved in pavement selection, with a spotlight on minimizing costs, curtailing traffic interruptions, and mitigating ecological impacts for the duration of the pavement’s life cycle.
... The base/surface courses with CEBM can facilitate to minimize the utilization of natural aggregates by replacing with recycled aggregates (Lyubarskaya et al., 2017;Flores et al., 2020). Further, the production of cold mix asphalt doesn't involve in heating of the aggregates which leads to reduction in energy consumption, temperature, and emissions of greenhouse gases (Zapata and Gambatese, 2005;Swaroopa et al., 2015;Ma et al., 2016;Chehovits and Galehouse 2010;Peng et al., 2015;Thives and Ghisi, 2017). Further, the workability of mixes can be achieved by using low-viscous binders such as emulsified bitumen or foamed bitumen. ...
The utilization of cold bituminous mixes in road construction is an environmentally and economically viable alternative to other stabilization processes. Besides, the incorporation of recycled materials into the cold mixes increases sustainability and decreases waste generation. The stabilization of Recycled Concrete Aggregates (RCA) with cement for pavement bases is a known one. However, the stabilization of RCA using bitumen emulsion is limited in nature. The present study evaluated the mechanical properties of the cold mixes prepared using RCA in different proportions (25%, 50%) with varying bitumen emulsion contents (5, 6, 7%). The compacted and cured samples are investigated for mechanical characteristics like density, Marshall Stability, Indirect Tensile Strength (ITS), Resilient Modulus, and permanent deformation. The dynamics of moisture evaporation and durability in terms of tensile strength ratios are studied. In the end, the vertical compressive and horizontal tensile strains of the pavement sections with bitumen emulsion stabilized bases are analyzed using IITPAVE software. The obtained results are compared using the critical strains calculated from the performance equations given by IRC (2018). It is noted that there is a decrease in the overall thickness of the pavement for the design traffic that varies from 5msa to 50msa. From this study, the base courses are recommended with bitumen emulsion treated RCA mixes, for traffic levels, up to 20 msa which would result in both -reductions in cost as well as the reduction in pavement overall-thickness. The present study also concluded that the optimum emulsion content of 6% does not show better resistance to permanent deformation. From the results, it is also suggested multi-variant mix-design criteria rather than a single indicative parameter
... Asphalt pavement is widely used in highway construction for simple construction, convenient material extraction and good performance (Chang et al., 2020;Zapata & Gambatese, 2005). The asphalt mixtures used in asphalt pavement construction and maintenance can be categorised into hot-mix asphalt (HMA) mixtures, half-WMA mixtures, WMA mixtures and cold-mix asphalt (CMA) mixtures according to the production temperature (Olard, Le Noan, & Romier, 2007;Olard, Le Noan, Beduneau, & Romier, 2008;. ...
... The research results of Zapata and Gambatese [20] indicate that the energy consumption during the construction process is mainly concentrated in three stages: mixing mixture, heating aggregate, and producing asphalt. Horvath and Hendrickson [21] consider the renewable capacity of asphalt pavement and believe that the environmental friendliness of recycled resources or waste pavement is better than that of new materials. ...
The energy consumption of expressway construction is so huge that it is important to strengthen the management of energy saving and emission reduction (ESER) of expressway construction. In this study, the latest literature on monitoring of energy saving and emission reduction of expressway pavement are reviewed from the following three aspects: the technology of energy saving statistical monitoring, research on benefit accounting of ESER, and research on application of energy consumption statistical monitoring. The purpose of this paper is to help establish a green highway pavement environmental protection evaluation system and a green low carbon construction technology system to promote the scientific development and green development of highway construction.
... Apart from the high energy consumption and GHG emissions, not only in the transportation sector but in our construction industry in general, resource consumption and the disorderly generation of waste have become a severe social and environmental concern [3][4][5][6][7]. In recent years, when environmental consciousness is on the rise, transportation officials and practitioners from the construction industry strive to implement a new framework of environmental responsiveness by making their practices and policies greener or more sustainable [8]. ...
Concrete paver blocks have recently developed as the most attractive and economically viable option for extensively recycling wastes. This deescalates the environmental concerns related to waste disposal, encourages conservation of natural resources, and contributes to a sustainable production process. In the present study, laboratory performance of concrete paver blocks using coarse and fine fractions of non-beneficiated reclaimed asphalt pavement (RAP) materials, derived as a waste residue from demolished asphalt pavement, was comprehensively and comparatively investigated. A two-factor analysis of variance and multiple comparisons test was performed to investigate the influence of RAP proportion and moist curing age. The laboratory findings revealed that the produced concrete blocks containing RAP have a great potential to be used for medium, heavy, and very-heavy traffic applications. The dosage of RAP as a natural aggregate replacement as well as the durability of RAP concrete can be increased using a staged mixing approach and a time-controlled dual-source compaction technique, which involves synchronized impact pressure and vibratory compaction energy. Moreover, assessing economic and environmental benefits highlighted the potentially sustainable aspects of recycling RAP fractions into precast concrete paver blocks.
... The base/surface courses with CEBM can facilitate to minimize the utilization of natural aggregates by replacing with recycled aggregates (Lyubarskaya et al., 2017;Flores et al., 2020). Further, the production of cold mix asphalt doesn't involve in heating of the aggregates which leads to reduction in energy consumption, temperature, and emissions of greenhouse gases (Zapata and Gambatese, 2005;Swaroopa et al., 2015;Ma et al., 2016;Chehovits and Galehouse 2010;Peng et al., 2015;Thives and Ghisi, 2017). Further, the workability of mixes can be achieved by using low-viscous binders such as emulsified bitumen or foamed bitumen. ...
The utilization of cold bituminous mixes in road construction is an environmentally and economically viable alternative to other stabilization processes. Besides, the incorporation of recycled materials into the cold mixes increases sustainability and decreases waste generation. The stabilization of Recycled Concrete Aggregates (RCA) with cement for pavement bases is a known one. However, the stabilization of RCA using bitumen emulsion is limited in nature. The present study evaluated the mechanical properties of the cold mixes prepared using RCA in different proportions (25%, 50%) with varying bitumen emulsion contents (5, 6, 7%). The compacted and cured samples are investigated for mechanical characteristics like density, Marshall Stability, Indirect Tensile Strength (ITS), Resilient Modulus, and permanent deformation. The dynamics of moisture evaporation and durability in terms of tensile strength ratios are studied. In the end, the vertical compressive and horizontal tensile strains of the pavement sections with bitumen emulsion stabilized bases are analyzed using IITPAVE software. The obtained results are compared using the critical strains calculated from the performance equations given by IRC (2018). It is noted that there is a decrease in the overall thickness of the pavement for the design traffic that varies from 5msa to 50msa. From this study, the base courses are recommended with bitumen emulsion treated RCA mixes, for traffic levels, up to 20 msa which would result in both -reductions in cost as well as the reduction in pavement overall-thickness. The present study also concluded that the optimum emulsion content of 6% does not show better resistance to permanent deformation. From the results, it is also suggested multi-variant mix-design criteria rather than a single indicative parameter.
... The paper itself did not report the LCA stages in detail. Examples of similar studies include comparisons of flooring materials (e.g., see [28,29]), roofing materials (e.g., see [30]), and pavement materials (e.g., see [31]), among others. ...
... To complicate impact assessment during the use phase, the allocation of impacts for in-use transportation infrastructure construction materials is particularly susceptible to the "washing machine effect", meaning there is often boundary overlap with other products, e.g., cars, tires, and gasoline (Cullen and Allwood 2009). Others have proposed procedures for assessing the A1-A5 stages of highway pavement projects (Zapata andGambatese 2005, Bhat et al. 2020), all life cycle stages of transportation infrastructure construction materials (Trigaux et al. 2017, Hasan et al. 2019, Saxe and Kasraian 2020, or cradle-to-cradle sustainability of buildings (European Commission 2022), but such procedures would be difficult to implement in design-bid-build (DBB) contract delivery mechanism predominately used in the U.S. The use and end of life stages for construction materials present further complexity than most manufactured products as these materials are in use for long periods of time and their use can occur in different future social and technical environments than exist today (Gantner et al. 2018). Based on the current limitations of extending beyond production stage, this study focuses on the application of cradle-to-gate EPDs for Buy Clean policies in the transportation infrastructure construction sector. ...
The use of EPDs in procurement of construction materials has been of increasing interest to government agencies, and adoption in the United States has been driven in part by “Buy Clean” legislation. Buy Clean encompasses green procurement policies that promote the purchase of construction materials and products with lower environmental impacts, considering the life-cycle impacts associated with those materials. Most EPDs for transportation infrastructure construction materials are “cradle-to-gate”, or representative of the material production stage of a product and not the entire life cycle; however, these EPDs can allow meaningful quantitative comparisons of environmental and sustainability indicators and serve as a mechanism for measuring improvements in environmental impacts during the production of materials. This paper describes how cradle-to-gate EPDs are used, presents a case study of initial implementation of an EPD policy by the Colorado Department of Transportation (CDOT), and provides recommendations to address some of the challenges that agencies and stakeholders can face when developing or participating in new EPD programs. It is desired that the recommendations and case study presented in this paper will help provide pathways to agencies for the successful enactment of Buy Clean policies and enable mitigation of actual or perceived barriers to program implementation.
... Rubberized asphalt results in higher carbon sequestration than conventional asphalt pavements using 1,600-2,000 tires per lane-mile 45 . Today, almost 12 million discarded tires are repurposed annually for rubberized asphalt 46 , a number that could substantially increase given the growing network of asphalt paved roads worldwide 47 It should be noted that there are other recovery routes for scrap tires that are out of the scope of this survey. One of these routes, for instance, is retreading (recapping or remolding), a re-manufacturing process that replaces the tread on worn tires and reintroduces them into the distribution circuit. ...
Applications of end-of-life tires (ELT) for energy recovery and new products can contribute to a circular economy. This paper reviews the environmental, health, and economic aspects of various applications of ELT, focusing specifically on the use of ELT in fuel, energy, and construction. Impediments to a more widespread application of repurposed ELT include a lack of streamlined handling and recycling processes; a poor understanding of the long-term ecological, human health, and safety consequences; and very few application-specific techno-economic assessments and life-cycle analyses. The prospects for rubberized asphalt as an economical and environmentally benign application of ELT are reviewed in four areas: (1) rubber pretreatment─the most effective techniques are chemical or microwave radiation, and the most sustainable technique is microbial devulcanization; (2) aging behavior─rubber particles delay aging in asphalt through several mechanisms; (3) techno-economic benefits─rubberized asphalt improves the cost-efficiency and energy-efficiency of asphalt; and (4) environmental emissions and leakage concerns─the risk of heavy metals and hazardous pollutants such as polycyclic aromatic hydrocarbons and volatile organic compounds contaminating the ecosystem or causing occupational diseases in workers. There are four priority directions for future research on rubberized asphalt: (1) determine the critical aging point; (2) describe the self-rejuvenating behavior; (3) quantify the long-term leachate under extensive weathering; and (4) compare the ecological aspects of pretreatment techniques in terms of potential greenhouse gas emissions and human health.
... It also compiles information on the energy use of the asphalt storage tank, aggregate drier, and mixer on-site. Because mixing and drying aggregate consume 48% of total energy consumption, lowering mixing and compaction temperatures has resulted in significant energy savings in asphalt pavement construction [16]. Asphalt facilities that use various sources of energy, such as diesel, electricity, and others, were surveyed for energy-related information in order to assess the effects of Sasobit Ò on the required energy. ...
Warm mix asphalt (WMA) is becoming more popular in the industry. The prospect of lower energy use, lower emissions, and a more usable product appeals to a sector under environmental pressure. WMA is a generic term for a number of technologies that allow the manufacturing of hot-mix asphalt (HMA) pavement material to be mixed and compacted at lower temperatures. WMA is blended and compacted at temperatures 20 to 50 degrees Celsius lower than traditional HMA. This paper presents a laboratory investigation of WMA mixes produced by an additive Sasobit Ò. The study also evaluates the effect of addition of Sasobit Ò on the rheology of viscosity graded asphalt VG 30. Two different percentages of Sasobit Ò were tested with VG 30. Results of binder rheology are presented in this paper. Laboratory study was conducted to investigate the properties of the asphalt mixes affected during development of the mix at lower temperatures. Warm mixes can be successfully created at lower temperatures than HMA mixes, according to the results of the evaluation. From the study of three HMA plants energy savings are found in case of WMA mixes with Sasobit Ò. Details about the energy consumed during various processes which occur during production are accounted in the study. It is concluded from the present study that use of Sasobit Ò lowers production temperatures by 40°C, which lead to a savings of about 25% in terms of fuel.
... Both the operation regime and the correctness of the operation, as well as the quality maintenance, have considerable effects on the value of the energy used. [4,5] 2 Synthetic report on the quantitative results of the energy audit Based on the energy audit and the energy balances, real and optimal, the quantitative and qualitative performances related to the explored processes were quantified, for the real situation and for the optimal situation (achieved following the application of the necessary measures to increase the energy efficiency). The results obtained are highlighted in tables 2 and 3, and diagrams and synthetic situations (Figures 2 and 3) [6]. ...
The paper is motivated by the need to provide relevant synthetic indicators, on the basis of which decision makers can evaluate and compare, the extent to which the proposed projects fall within the goals of sustainable development - economic efficiency, environmental responsibility, social solidarity, circular economy, production and responsible consumption. The case study, introduced in the paper, refers to the real and optimal thermal energy balance, made for an installation for the preparation of asphalt mixtures. The approached example took into account the perspective of multiplication and modernization of asphalt mixture preparation stations. Based on the measurements, performed “on site” and the calculations performed, the values of some indicators referring to energy performance, economic efficiency and environmental impact were obtained. The obtained indicators were aggregated in a global indicator, useful for administrative decision makers.
... Stripple [29], through their study, which included accessory facilities of a highway, concluded that the energy consumption of cement concrete pavements is higher than that of asphalt concrete pavements. Zapata and Gambatese [30], by analysing the energy consumption of asphalt concrete pavements and continuous reinforced concrete pavements, found that the continuous reinforced concrete pavement consumes more energy in the production and construction stage of materials, including the energy consumption of cement production. The energy consumption of cement production is the main factor, while the drying energy consumption of mixed aggregates is a significant factor affecting the energy consumption of asphalt pavement. ...
The most well-known and used evaluation system to determine the life cycle of a product, is the life cycle assessment (LCA). In Europe, the use of the life cycle assessment (LCA) to assess the environmental performance of products is becoming commonplace, which is why substantial efforts have been made in the last two decades to develop new life cycle assessment (LCA) methodologies and software. This paper evaluates the life cycle assessment (LCA) for the rehabilitation of a national road sector in Romania. The biggest ecological problem facing mankind is the effect of global warming and climate change associated with this phenomenon, due to the increase of the concentration of pollutants to the atmosphere, and this paper presents the results of the life cycle assessment (LCA) based on a cradle-to-gate approach. For this case study, were used three rehabilitation alternatives. These alternatives and the existing pavement structure were analysed using the GaBi software, Ganzheitlichen Bilanzierung (German for holistic balancing), to assess the environmental impact of global warming, the stratospheric impact of ozone, and the impact on human health. The results obtained in this study illustrate the importance of a life cycle assessment approach for evaluating the sustainability for different designs and for the construction of road rehabilitation options.
... Larger coarse aggregate sizes tend to make concrete appear nonhomogeneous and have a smaller surface area, both of which can contribute to the generation of weaker bonding forces, both of which contribute to the development of lower strengths [2]. This aspect of limited to concrete strength below 30 MPa without additional additive on the mixtures [17,18]. ...
The aggregates in a concrete play a role in both strength and durability. Without a change of doubt, aggregates have a significant impact on mechanical, fresh and long-term performance properties of concrete. Low quality aggregates will give low behaviours that affect the condition of the concrete. In this investigation, improvement of local’s aggregate - natural mount sand and uncrushed mount gravel taken from Lumajang, Pasuran and Bangkalan, used as the parameter study. This study is conducted to support the low characteristics aggregate in terms of water absorption, sorptivity and compressive strength concrete. Three mixes variables are used based on w/c content, 0.40, 0.35 and 0.30 reflected the concrete quality. On the other hand, concrete mixes with locally grading group are 80 % aggregate from Bangkalan and 20 % aggregate from Lumajang or Pasuruan + Bangkalan (M4 and M5). The results indicated that the M4 and M5 grading group concrete mix had the maximum compressive strength out of the eight different concrete mixes. This particular mixture also improves the water absorption and sorptivity of the concrete. HIGHLIGHTSTen concrete mixes with three concrete types were prepared using mount sand uncrushed mount gravel, with respect to understanding mechanical and physical properties comparing to 28-day compressive strength results. Those three mixes, M1, M2 and M3, provided to give the alternative of using unused coarse aggregate with low characteristic under three different w/c ratio i.e., 0.40, 0.35 and 0.30. Those conditions relate to the concrete quality - minimum compressive strength that normally used in the construction. Low characteristic aggregate, without a doubt impacting on long term performance properties of concrete structure. Locally available materials taken from Lumajang, Pasuruan and Bangkalan were used as the combined grading group of fine and coarse aggregate in each mixture. It was found that the optimum combine grading group was fine aggregate from Bangkalan + coarse aggregate from Lumajang or Pasuruan + Bangkalan (M4 and M5). Using M4 and M5 grading group, results indicated that, the highest compressive strength among the eight concrete mixes. In addition, these concrete mixes also illustrate to have low sportively and water absorption. GRAPHICAL ABSTRACT
... Increased wildlife mortality, restrictions on animal movement, pollution (chemicals, noise, light), and the spread of invasive species caused by road construction under the BRI could have negative impacts on terrestrial biodiversity [36]. Raw material extraction for building roads or supplying resources for new population centers (e.g., power supply) [37] and increased access to natural resources due to greater accessibility along the route [38] could also affect biodiversity. ...
The “Belt and Road” Initiative (BRI), i.e., the official Chinese term for the “Silk Road Economic Belt” and the “21st Century Maritime Silk Road”, was proposed to share China’s development opportunities with BRI-related countries and achieve common prosperity. Though the BRI itself conveys rich social and economic connotations, ecosystem health and the environmental problems in the Belt and Road regions are scientific issues. In this study, papers relating to the ecological issues of the BRI between January 2013 and December 2021 were collected and analyzed via CiteSpace. We found that some ecological issues were involved with the environmental challenges posed by the BRI, whereas others were, to a certain extent, subjective assumptions. Accordingly, we identified and classified the limitations and constraints of those environmental views about the BRI. By emphasizing that scientific data is key to explaining the ecological problems, we advanced four prospects for ecosystem health and environmental geography studies in the Belt and Road regions: (1) Spatial analysis and monitoring technology for the environment; (2) Clarification of the characteristics and mechanisms of the ecosystem and environments; (3) A focus on the interaction between the economy and the environment; (4) Specific and targeted strategies and solutions to different environmental problems.
... Moreover, roads are responsible for their users, including car drivers, pedestrians, and goods, to provide comfort and safety for them [3,4]. Nowadays, asphalt mixtures are more in demand than concrete mixtures in road constructions because asphalt mixtures can bring high skid resistance, uniform surface, lower traffic noise generation, and more cost-effectiveness than concrete mixtures [5][6][7]. ...
Asphalt mixtures are the major constituent of road constructions. Those mixtures expose to high-temperature levels during the construction process and their life cycle. The bitumen aging occurred because of the harmful effects of elevated temperatures upon the asphalt mixtures, which leads to oxidation, evaporation, and physical hardening within the bitumen structure. The aging phenomenon can intensify the hardness and brittleness of bitumen, which negatively affects the performance of asphalt mixtures. Researchers have investigated different types of bitumen additives to diminish the negative effects of bitumen aging, among which biomass additives are more attractive for researchers because that additives are organic and mainly emanate from waste materials. The current study investigated the effect of calcium lignosulfonate (CLS) at four quantities (i.e., 5%, 10%, 15%, and 20% by the weight of base bitumen) as an antiaging bitumen additive on physical, workability, thermal susceptibility, rheological, and chemical properties of 60/70 penetration grade bitumen. The results revealed that although the addition of CLS into the bitumen enhanced the rigidity of bitumen against rutting failure at high-temperature conditions, the CLS-modified bitumen was more susceptible to fatigue failure than the virgin bitumen at low-temperature regions. The workability analysis showed that the CLS powder could improve the bitumen’s consistency against permanent deformation at high-temperature levels. Although the bitumen’s viscosity increased because of CLS modification, the CLS-modified bitumen provided acceptable workability based on the Superpave specifications. Outcomes from the rheological test revealed that the addition of CLS into the bitumen improved the rutting resistance of bituminous mixtures at high-temperature levels. The SARA analysis indicated that the hardening of CLS-modified samples emanated from the formation of asphaltenes within the bitumen because of CLS incorporation. Different types of aging indices, including PRP, SPI, VAI, and AIRF, which were calculated in this research, showed that the presence of CLS within the bitumen could retard the bitumen’s aging process.
... From the previous investigations (Zapata and Gambatese 2005, Thenoux et al. 2007, Horvath 2004, Ventura et al. 2009), the fuel energy commonly used in the asphalt mixing stage included coal and heavy oil, whereas coal gas and natural gas, as emerging environmental energy, were being applied in highway construction gradually. Different types of fuel had different advantages and disadvantages. ...
In order to evaluate the energy consumption and emission reduction effect of warm mixed asphalt (WMA) comprehensively and precisely, a novel evaluating method of the effect of WMA on emission and energy consumption of asphalt pavement construction was established and applied on the road construction project in northeast region of China. Considering the production of asphalt mixture and construction process of road engineering, a series of evaluating indices were selected and divided to the Level I and II indices respectively for establishment of evaluating system. Then, the level ranking intervals of Level I and II indices were confirmed based on the Hierarchical cluster method and Bayesian method. Finally, the single index evaluation (SIE) and multi-objective comprehensive evaluation (MOCE) methods were combined to evaluate the reducing effect of WMA on the emission and energy consumption during the highway construction process of project in northeast region of China. The results indicated that i. target WMA could achieve excellent reduction effect on COx and the reduction rate was above 60% and also promote the reducing effect on NOx and SO2 emitted during the production process of asphalt mixture. ii. The improving effect of WMA on emission was mainly reflected in the production stage of asphalt mixture rather than construction stage. iii. The application of WMA could help saving energy consumption obviously in transportation and onsite construction of asphalt mixture. This evaluating index system and method could provide reference for the reduction effect evaluation of WMA in road construction, which could help promoting the wide application of WMA in further road construction project.
... Die höheren Herstellungskosten werden folglich durch die Langlebigkeit kompensiert [9]. Auch zeigen DBB im Vergleich zu konventionellen Bauweisen Vorteile hinsichtlich Klimabilanz und Ressourcenverbrauch [10], [11]. Während im Ausland Regelwerke und Anwendungsempfehlungen bestehen [12], die auf langjährigen Erfahrungen basieren, wird in Deutschland auf Basis der in-und ausländischen Erfahrungen dimensioniert [8]. ...
Stetig steigende Verkehrsbelastungen führen bei den Standardbauweisen des Verkehrswegebaus zu immer kürzeren Nutzungszeiträumen zwischen Erhaltungsmaßnahmen und grundhaften Erneuerungen. Die Verwendung einer langlebigeren Bauweise bietet in diesem Zusammenhang und im Hinblick auf die Wirtschaftlichkeit ein enormes Potential. Während im Ausland bereits seit geraumer Zeit durchgehend bewehrte Betonfahrbahnen eingesetzt werden, sind diese in Deutschland bislang auf wenige Streckenabschnitte begrenzt. Fehlende technische Regelungen sowie eine systematische Betrachtung der Optimierungspotenziale, insbesondere in Hinblick auf die Risssteuerung, hemmen die praktische Umsetzung. Im Zuge dieses Beitrages werden Erkenntnisse zu Rissmechanismen und Einflussfaktoren auf die Rissbildung in durchgehend bewehrten Betonfahrbahnen tiefergehend betrachtet. Dabei werden Versuche mit verschiedenen Randbedingungen im Hinblick auf Rissbildung und Rissverlauf infolge unterschiedlicher Einwirkungen, z. B. aus Hydratation, variierenden Umgebungsbedingungen und Verkehrslasten, ausgewertet. Daneben liefern numerische Untersuchungen zum Einfluss der Hydratation in Abhängigkeit des Erhärtungsbeginns zu unterschiedlichen Tageszeiten und variierender Frischbetontemperaturen neuere Erkenntnisse.
... Varying estimates of the embodied energy used in asphalt production come to an average of about 3 megajoules for each kilogram (about two pounds) of asphalt produced. This is equivalent to the energy required to power a typical household in the United States for one hour [35,36]. In total, road construction is estimated to require between 2 and 4 terajoules (about 600 and 1200 kWh) per lane-kilometer of roadway paved. ...
The structural changes in an economy that accompany its growth to high-income status have been predictable in Europe, the United States, and Asia, characterized by declining employment in agriculture and rising levels of urbanization driven by jobs in the modern industrial sector. As agricultural productivity rises, the share of people employed in agriculture declines, and both urbanization and employment in manufacturing increase. Food prices fall relative to wages, causing the share of income spent on food to decline to very low levels. Asian countries have followed a similar path, although at a much faster pace. Africa, however, is different. Despite a high share of the population in urban areas, most African countries have yet to see significant increases in agricultural productivity that might drive industrial growth and jobs. The rising share of urban population has not been matched by increases in agricultural productivity, falling food prices, or the emergence of a viable industrial sector. Available evidence shows that agricultural yields in Africa are low and food is costly, while the share of employment in agriculture remains high. For the process of structural transformation to get underway, African countries must invest in the manufacture of fertilizer, develop better methods of water control, improve transportation, and invest in cold storage. Each of these interventions requires significant amounts of energy, including energy from fossil fuels, and they are not replaceable—countries have managed structural transformation in different ways but to date none have leapfrogged the process.
A aplicação de ferramentas que possibilitem uma avaliação quantitativa dos impactos no meio ambiente oriundos dos projetos de infraestrutura é uma demanda global na busca da sustentabilidade. No contexto brasileiro, esse tipo de avaliação ainda não se apresenta como prática consolidada nos estudos de projetos de infraestrutura de transportes. Diante disso, este artigo visa apresentar um método inteligível e eficaz para cálculo do consumo energético e da emissão de CO2 em serviços de infraestrutura, com base em dados referenciais do SICRO, de forma a impulsionar esse tipo de avaliação em empreendimentos de construção pesada. Para testar sua validade, o método é aplicado para comparar serviços de dois tipos de pavimentos, o asfáltico e o de concreto de cimento Portland. Os valores obtidos por quilômetro por ano apontam um consumo energético 4,8 vezes maior para a solução-tipo asfáltica em relação ao pavimento de concreto. No que diz respeito à massa de CO2 emitida, a solução de concreto apresentou uma contribuição 51% inferior à asfáltica. A presente pesquisa se configura como relevante contribuição para a tomada de decisão entre diferentes soluções construtivas ao quantificar de forma acessível parâmetros de impacto ambiental a partir de dados nacionalmente difundidos e que já integram os projetos de infraestrutura de transportes, como os do SICRO, além de agregar nova utilidade às composições de custos desse sistema.
The use of warm asphalt mixtures has been increasing continuously in recent times as a promising alternative, as it leads to lowering the manufacturing and application temperatures, and thus it saves energy, reduces fuel consumption and reduces emissions. On the other hand, the possibility of using waste materials in the creation of heated mixtures increases the positive effects on the environment and the economy because using waste instead of virgin (raw) materials helps to lower extraction costs and ease landfill strain. The feasibility of employing sulfur waste (SW) instead of the conventional mineral filler (CaCO3) for warm mix asphalt (WMA) mixtures is explored in the current study. The WMA mixes were produced by using synthetic zeolite (SZ) with a concentration of 5 percent (by weight of asphalt cement). Four WMA mixes were made, three of which were made using SW at different percentages of 4, 5, and 6 percent (by weight of aggregate), and a reference one using regular filler (CaCO3) at 5 percent (by weight of aggregate). Marshall stability, Marshall quotient, indirect tensile strength at 25 and 60 °C, tensile strength ratio, rutting resistance in Kim test and Semi-Circular Bending (SCB) Fracture test were the mechanical parameters that were assessed. The results of the tests showed that a slight change occurred in the Marshall stability of the SW mixtures, while a significant decrease in the flow values and air voids of the warm mixtures containing SW compared to the WMA control mixture. As a result, the Marshall quotient values for these mixtures increased, and thus the SW mixtures meet the requirements of ASTM for Marshall properties deservedly, the deformation strength is also optimized for SW mixtures. Perhaps the most important improvement is in the tensile strength ratio (TSR), where the TSR values increased by 36.94%, 50.84% and 54.46% for the SW mixtures SW4%, SW5% and SW6% respectively, compared with the reference WMA, it was concluded that it is possible to use sulfur waste in the production of warm mixtures, as it contributes to improving the properties and its transportation cost is lower compared to the traditional filler (CaCO3).
Despite positive changes in the road construction associated with the implementation of national projects aimed at a significant increase in the qualitative and quantitative indicators of the road and transport infrastructure, the resource conservation, environmental protection and safety remain relevant due to insufficient attention to them.
Purpose: The analysis of the relationship between quality indicators and environmental safety of the road in the sustainable development.
Approach: Balance is considered between ecological, social, economic components of the road transport infrastructure. The integrated development of road construction should serve as a functional basis of this infrastructure at all stages of the life cycle: the road design, construction, operation.
Research findings: The correspondence of the actual situation in regions to modern regulatory and legal documents and economic possibilities of their implementation is considered herein. The impact of construction and operational and technological means on the environment is shown for the road life cycle. It is shown that the road construction must be oriented towards the use of innovative development that improves the quality and safety of the road transport infrastructure while addressing issues of resource conservation and environmental management.
This study provides a holistic list of factors that affect highway sustainability (HWS) and determines the most significant factors throughout the triple-bottom-line of sustainability. Previous studies analyzed many factors related to sustainability performance in highway projects during their life cycle, whereas the social sustainability aspects were commonly ignored. In addition, there is imperative to consider the Sustainable Development Goals (SDGs) of highway projects in local and global future visions. On the other hand, the infrastructure rating systems specified different thresholds to achieve sustainable highways. Thus, this study analyzed published articles, SDGs, and infrastructure rating systems to extract the most important factors affecting HWS. A content analysis was conducted to specify the most relevant publications in HWS, which are strongly related to the research keywords. According to the content analysis, 150 articles out of 6,422 were selected for further investigation. Social Network Analysis (SNA) analyzed and ranked 224 factors that were extracted from the aforementioned sources to determine the factors of utmost importance. We found that 78 factors out of 224 are of paramount influence on HWS. Finally, the evaluation of the most widely used infrastructure rating systems revealed a shortage in the common factors affecting the HWS.
Tahapan pembangunan jalan dari tahap konstruksi ke tahap operasi, mengkonsumsi sejumlah besar energi serta menghasilkan emisi. Penelitian ini bertujuan menganalisis jumlah energi dan emisi gas rumah kaca (CO2) pada pekerjaan jalan dengan perkerasan lentur (aspal) dan perkerasan kaku (beton) dengan menggunakan pendekatan Life Cycle Assessment (LCA). Studi kasus dilakukan pada ruas jalan di Provinsi Kalimantan Tengah. Metode yang digunakan untuk mengestimasi konsumsi energi dan emisi Gas Rumah Kaca (GRK) yaitu metode Tabel Energy Use and GHG Emissions for Pavement Construction dan Metode Konversi Bahan Bakar yang mengacu pada prosedur standar Intergovernmental Panel on Climate Change (IPCC). Hasil perhitungan, dengan pendekatan LCA jumlah konsumsi energi untuk konstruksi perkerasan kaku berjumlah 612.16 GJ dan perkerasan lentur berjumlah 268.91 GJ. Hasil perhitungan total emisi menunjukkan perkerasan lentur sebesar 19949.38 kgCO2/km dan perkerasan kaku sebesar 45414.75 kgCO2/km. Kesimpulan penelitian ini bahwa perkerasan lentur lebih ramah terhadap lingkungan dan lebih berkelanjutan dibandingkan dengan perkerasan kaku.
Brazil’s dependence on road transportation, combined with the high extent of the network and the lack of investment management in maintenance and restoration, makes traffic conditions poor, resulting in unwanted costs and environmental impacts. Life cycle assessments are a promising tool that assists in decision making. This study aimed to evaluate the environmental performance of three roads, applying different restoration and maintenance techniques throughout the analysis cycle. To develop this study, the ecoinvent database and the OpenLCA software were used to model, based on studies developed in the HDM-4 (Highway Development and Management) software, and the interventions were applied for the initial year and for 30 years. Using the life cycle assessment methodology, the environmental impacts generated for the categories of acidification, climate change, eutrophication, ecotoxicity, human toxicity and photochemical oxidation were identified. The results show that, when analyzing the restorations in their implementation, deep recycling generates more environmental impacts; however, when planning the restorations throughout the cycle, deep recycling becomes, on average, 47% less impactful than the structural reinforcement technique, which is the same behavior that has been identified with the Whitetopping technique. It becomes evident that the use of rigid structures, such as Whitetopping or semi-rigid structures and deep recycling with Portland cement additions, generate fewer environmental impacts when compared to flexible structures that consume a large amount of asphalt binder, and that require interventions at shorter intervals.
Road construction work from the construction stage to the operation stage, consume a large amount
of energy and produce emissions. This study aims to analyze the amount of energy and greenhouse
gas (CO2) emissions from road works with flexible pavement (asphalt) and rigid pavement (concrete)
using the Life Cycle Assessment (LCA) approach. The case study was conducted on roads in Central
Kalimantan Province. The method used to estimate energy consumption and Greenhouse Gas (GHG)
emissions is the Energy Use and GHG Emissions for Pavement Construction Table method and the
Fuel Conversion Method, which refers to the standard procedure of the Intergovernmental Panel on
Climate Change (IPCC). The results of calculations at the production and construction stages, the
energy consumption for rigid pavement construction is 612.16 GJ, and flexible pavement is 268.91
GJ. The result of the total emission calculation shows that flexible pavement is 19949.38 kgCO2/km,
and rigid pavement is 45414.75 kgCO2/km. This study concludes that flexible pavements are more
environmentally friendly and sustainable than rigid pavements.
In recent years, there has been a sharp rise in the number of life cycle assessment (LCA) studies related to road pavements and road infrastructures. The main aim of this study is to perform a critical analysis of various studies undertaken so far to examine goals, scopes, impact categories, life cycle phases, methods and approaches, and limitations. A total of 67 LCA studies reported in literature were analysed and categorized into four categories viz. flexible pavement; rigid pavement; flexible and rigid pavement; and road infrastructure. The analysis revealed that 80% of the studies were carried out in developed countries while just 20% of studies were from developing countries. Most of the road pavement LCA studies (∼76%) considered material and construction phase and assessed the impacts in terms of only two impact categories viz. global warming potential and energy demand. Only 10-15% of studies considered a wide range of impact categories and used commercial software such as GaBi and SimaPro for impact assessment. 19 studies were on flexible pavements, 4 on rigid pavements, 30 on both flexible and rigid pavements and 14 on infrastructure. Bridges, tunnels, drainage, lighting, and road marking were the major components of road infrastructure studied while other road infrastructures such as culverts, toll plazas, and vehicle underpasses were not included. Majority of the studies depended on secondary or background data for the development of life cycle inventory. Out of 67 studies, only 18 studies performed the sensitivity analysis while only 6 studies carried out uncertainty analysis. There is a need for inclusion of all supporting infrastructures along with road pavement, and also for paying greater attention to sensitivity and uncertainty analysis in studies pertaining to the transportation sector. During construction phase, no LCA study considered the important impacts due deforestation, defragmentation, restriction of free wildlife movement etc. Hence, future LCA road studies must evaluate the negative consequences of these as well as integrate social and economic impacts via Multi-Criteria Decision Making to make LCA a robust decision-making tool for sustainability.
With the increasing price and carbon dioxide emission of cement comes the challenge of rigid pavement. One of the solutions to address this issue is minimizing the cementitious paste volume (CPV) of the concrete mix with the blended aggregates (BA) technique. This paper presents the effects of minimizing the CPV in Portland limestone cement (PLC) concrete with CPV reduction and BA application for Florida rigid pavement concrete. The findings indicated that reducing the CPV in the pavement concrete mix to some extent would not adversely affect the properties of the pavement concrete; the minimum CPV of PLC pavement concrete mixes can be reduced to 22.5% with no loss in the properties of fresh and hardened concrete. The other benefits of CPV reduction include low permeability and shrinkage strain. In summary, minimizing the CPV and utilizing the BA technique can be considered to design sustainable pavement concrete mixes with better pavement performance, lower materials costs, and lower global warming potential.
Higher energy requirement for asphaltic layer construction with asphalt binder containing reactive elastomeric terpolymer (RET) and poly phosphoric acid (PPA) can be addressed to a greater extent with the addition of warm mix asphalt (WMA) additives. However, moisture damage related problem is one of the concerns with such addition, which further aggravates with an increase in ageing level. The addition of lime may help in addressing moisture damage related problems in such cases. Previous research works show that based on the interaction between asphalt binder and particular WMA additive, the viscosity may undesirably increase also. So far, the influence of different WMA additives (wax, chemical surfactant (CS) and water-based (WB)) on the workability related properties of asphalt binder containing RET and PPA is not understood. It is also not clear if such warm mix additives with/without lime can help in improving long-term bonding with different aggregate types or not. Therefore, this research work aimed at identifying the appropriate WMA additive (with/without lime) which can help in (a) addressing the workability related problem and (b) improving long-term bonding with different aggregate types. To achieve this, different types of WMA additives (with/without lime) were added to RET and PPA modified binder. Viscosity-based measurement and chemical analysis using Fourier transform infrared spectroscopy were performed to understand workability and underlying chemical changes. Results indicated that although wax and CS-based warm mix additives can help in reducing energy demand, the addition of WB warm mix additive will have a negative impact from the workability perspective. Likewise, dynamic contact angle for different binder combinations was measured to evaluate the surface free energy components, which further helped to examine the long-term bonding with different aggregate types. Among different WMA additive types, the use of wax-based WMA additive was found to be most effective in improving compatibility with different aggregate types. Also, irrespective of the binder combination, the addition of lime improved the long-term bonding with considered aggregate types.
Reducing environmental impacts in transport motivates many studies to offer more sustainable freight services. However, most methodologies focus on impacts from fuel consumption, and approaches trying to integrate other transport components have not facilitated its application to actual and specific transport services. In this study, we present a harmonized approach to address the transport services with a holistic way to increase the knowledge about hotspots of the transport sector based on the life cycle assessment methodology. In this framework, vehicle manufacturing, fuel production, and infrastructure construction are the key transport components around the traffic process. Besides fuel usage, the operation and maintenance of vehicles and infrastructures are also included. We developed a tool to create the life cycle inventories for each transport component to be applied to specific transport services in any location with a comprehensive view and low uncertainty in the results. This approach was applied to road-freight services in Colombia, Malaysia, and Spain. The main results showed the nature and origin of the environmental impacts, which are highly influenced by the emissions control technologies, road characteristics, and traffic volume. The contribution of atmospheric pollutants per tonne-km can decrease by a quarter when Euro VI trucks on highways instead of conventional trucks on single-lane roads are used. However, these contributions are highly affected by fuel production due to the origin of biofuels. The proposed methodology provides relevant information to estimate transport impacts in the life cycle assessment of products with superior precision and identify strategies for systemically improving sustainability.
This study conducts a comprehensive life cycle assessment (LCA) on converting waste vehicle tyres into recycled crumb rubber (CR) granules as an alternative polymer for enhancing asphalt properties. The LCA study has been performed on acquired industrial primary data by incorporating CR at different proportions of binder in one ton (1-ton) of asphalt mix following the wet method. The uncertainty analysis of design variables identified a relatively strong positive relation of emissions with the equipment energy consumption (r = 0.98). Monte Carlo simulations evaluate the potential renewable sources (solar, hydro, and wind) in sequence over fossil fuels for the possible transition in the Australian grid by 2030 and 2050, as per the Paris Agreement. 71.91% reduction of CO2 emissions is achievable by recycling vehicle tyres into crumb rubber compared to landfill and incineration. Recycling by-products of CR production, such as steel and textile, significantly mitigates negative impacts. A decrease of 2.23% emissions was associated to the use of crumb rubber as a binder modifier in the asphalt mixture via the midpoint assessment. In endpoint LCA, a higher association of resource (US$) saving costs was observed than for other protective zones, i.e., human health and ecosystem damage. Recycling 466,000 tonnes of disposable waste tyres contributes to 16.1 million US$ worth of resource savings. An equitable industry-based LCA and uncertainty analysis of design parameters can assist in prioritizing suitable options to improve efficiency and future emission strategies on a global scale.
The activity of material transportation regarding the project of road construction indicated several negative impacts on the environment including the greenhouse gas emissions release. In developing sustainable development strategy especially in transportation infrastructure, it is necessary to find a strategy in reducing greenhouse gas emissions of road construction cycle. This study aimed to estimate and evaluate the greenhouse gas emissions reduction in the flexible pavement material transportation process unit. The life cycle assessment was used to estimate the emissions produced. The greenhouse gas emissions evaluation did not only underline the reduction percentage, but also on the relative cost of the reduction. The approach of cost effectiveness analysis concept was implemented to estimate the cost effectiveness. The results showed that the greenhouse gas emissions in the dump trucks use variation in the flexible pavement material transportation process unit ranged from 2.99% to 6.23%. Every alternative in emissions reduction showed the potential to decrease the greenhouse gas emissions at a cost comparable to emissions that could be reduced.KeywordsCost effectivenessGreenhouse gasesFlexible pavement
Material transportation of the road construction project has had some negative impact on the environment, one of which is the release of greenhouse gas emissions. In an attempt to develop sustainable strategy, there is a need to identify and quantitatively evaluate the GHG emission reduction opportunities that exist in material transportation of the rigid pavement life cycle. The aims of this study is to estimate and evaluate the reduction of greenhouse gas emissions in the rigid pavement material transportation process unit. The life cycle assessment was used to estimate the greenhouse gases emissions. The evaluation of greenhouse gas emission reductions is not only on the percentage of the reduction, but also on the cost effectiveness of the reduction. The cost effectiveness analysis (CEA) was used to calculate cost effectiveness. The result shows that a reduction in greenhouse gas emissions in the variation of the use of dump trucks in the rigid pavement material transportation process unit ranged from 2.89% to 6.24%. Each alternative to reducing emissions has the potential to reduce greenhouse gas emissions at a cost comparable to reduced emission.KeywordsReducingGreenhouse gasesRigid pavement
The damage of expansion joints is a common problem of bridges, which adversely affects not only driving comfort and safety but also the durability of the structure. Jointless bridges can fundamentally solve this fragile problem. However, how to accurately assess its environmental and economic benefits has not been studied, specifically as climate change intensifies. To address these issues, this study first examines the effects of climate change on design expansion allowance of bridge expansion joints based on climate projections. Subsequently, the life-cycle environmental and economic benefits of two jointless bridges located in Beijing–Hong Kong–Macau Expressway are quantified under climate change scenarios. Moreover, uncertainty and random forest algorithm-based importance analyses are carried out to help decision-makers identify major environmental and economic factors and develop eco-friendly plans to facilitate jointless bridge construction. Results indicate the following: (1) the design expansion allowance of bridge expansion joints tends to increase with the time-dependent temperature and humidity; (2) the avoidance of traffic detours caused by the maintenance and replacement of expansion joints is a major source of life-cycle environmental and economic benefits; (3) traffic detour distance is the most important factor influencing the life-cycle environmental and economic benefits.
Asphalt production has been known as one of the major contributors to the production of
polycyclic aromatic hydrocarbons and has been considered highly inappropriate. According
to numerous reports, about 25 percent of global carbon dioxide pollution has been caused by
the transportation industry and much of it is during the construction and operation of roads.
On the other hand, road and pavement activities always require extensive investment and
use of large financial resources. As well as the use of bitumen in asphalt practices and the
sudden increase in the price of this material in the last few years there have been major
problems in the implementation and operation of asphalt pavement, so the use of alternative
pavement procedures can eliminate many problems in this area.
On the other hand, in industrial road paving, due to the heavy machinery traffic and heavy
load on the pavement, the importance of achieving proper durability and resistance is
doubled. These reasons have led researchers in this field to research the properties of roller
concrete, especially durable roller concrete. Therefore, considering the increasing use of
roller concrete in road pavement construction, investigating the factors affecting the quality
of these pavements is of great importance. One of the important parameters that are
considered today in the implementation of different types of concrete structures is its
durability.
In this research, we have tried to evaluate the durability of these types of concrete by 11
concrete mixing designs. Considering previous studies and optimum quantities, these
designs include 4 designs with silica and 4 designs containing cement slag replacement with
1% by volume polypropylene fibers and 1% by weight of steel fibers, as well as 3 control
designs. The experiments were performed on 165 samples. To test volumetric permeability
of 28-day cylindrical specimens with a diameter of 75 mm and a height of 150 mm, for tests
of electrical resistance, electrical conductivity and migration coefficient of chloride ion of
cylindrical specimens with a diameter of 100 mm and a height of 200 mm, and to test the
durability of concrete sulphate from cubic water *. 100 * 100 is used.
The interest toward life cycle assessment studies in the construction industry has been increasing in the last decades. However, there is no existing study that focuses on mapping the scientific research of the LCAs in the construction industry with a comprehensive understanding. Hence, an expansive and macro level review of the LCAs within the subject domain is needed to fulfill this gap in the literature. The research objective of this study is to reveal the status quo, hot topics and keywords, and emerging areas of the LCA research in the construction industry. For this purpose, a systematic bibliometric and scientometric analyses were conducted by referring 2885 bibliometric records published between 1997 and 2021 (end of February). The analysis indicated the countries China, USA and Spain as the most productive countries in the field. Additionally, hot keywords in the domain revealed as ‘energy’, ‘environmental impact’, ‘sustainability’, ‘performance’, ‘emission’, ‘building’, ‘system’, ‘design’, ‘concrete’. ‘Circular economy’, ‘mechanical property’, and ‘footprint’ are found as the emerging areas of this field. Document co-citation clusters showed the hot research themes of the domain as building information modeling (BIM), energy performance, construction and demolition waste, carbonation, water supply, bridge design, optimization, pavement management, ventilation and design assessment. The results of this research make a significant contribution to the scientific community and industry practitioners by providing an inclusive understanding of the recent status, hot keywords and topics, and emerging areas of life cycle assessment in the construction industry. Further, this study would be a useful and valuable reference and guideline for the researchers interested in this field.
The public, industry, and governments have become increasingly interested in green design and sustainable development. Construction activities affect the environment significantly, so environmental issues should be considered seriously. Thousands of miles of roads are paved every year with asphalt and steel-reinforced concrete. What are the environmental effects of the two materials? If asphalt has been used overwhelmingly over concrete, is it a better choice for sustainable development? We present results of a life cycle inventory analysis of the two materials based on publicly available data. We find that for the initial construction of equivalent pavement designs, asphalt appears to have higher energy input, lower ore and fertilizer input requirements, and lower toxic emissions, but has higher associated hazardous waste generation and management than steel-reinforced concrete. When accounting for the uncertainty in the data and when annualizing environmental effects based on assumed average service lives of the two pavement types, the resource input requirements and the environmental outputs are roughly comparable for the two materials. However, asphalt pavements have been recycled in larger quantities than concrete pavements, with consequent resource savings and avoided pollution, which suggests that asphalt may be a better choice from a sustainable development viewpoint. Of course, special functional requirements or economics may dictate the use of one material over the other in particular applications regardless of the overall environmental effects.
The object of the study has been to assess the environmental impact of concrete and asphalt road pavements. The assessment is based on the estimation of service life of road pavements and the environmental burdens caused by their production, use and disposal. Also taken into account is the influence of the pavement on fuel consumption by traffic, noise, lighting requirements and dust formation. The functional unit studied is 1 km of pavement of the Tampere motor way assuming passage of 20 000 vehicles per day. The time scale is 50 years. On the basis of the results the environmental burdens of concrete pavements significantly depend on the cement content of concrete. Consequently, the environmental profile of concrete pavement also significantly depends on the depth of the concrete layer. The environmental burdens from paving and maintenance are rather low compared with those caused by production processes of high-strength concrete. On the contrary, the significance of lighting during 50 years is high. The dust emissions of the concrete pavement studied are mainly induced by abrasion and salting of the pavement. The significance of pavement materials, paving, maintenance and lighting is low compared with the environmental burdens caused by traffic during 50 years. With respect to the effect of material properties of pavement on fuel consumption, it was assumed that the influence on fuel consumption related to the surface texture is the same for both pavements, the difference in E-modulus does not influence the fuel consumption for the heavy vehicles and that the measured differences in rolling resistance have no influence on fuel consumption. However, any difference in fuel consumption of traffic due to pavement materials would significantly affect the result. For example, a roughly 0.1 - 0.5% decrease in fuel consumption of traffic due properties of concrete pavement would bring "savings" in emissions of the same order of magnitude than those from all the other parts of the life cycle of concrete roads. On the basis of the results the environmental burdens of asphalt significantly depend on the bitumen content of asphalt. In addition, the manufacture of asphalt including drying of aggregate materials significantly accounts for the environmental burdens of asphalt pavement. The result also significantly depends on the maintenance operations presumed. The result was assessed using different valuation methods. The differences between asphalt and concrete scenarios are rather low according to the Swiss, Dutch and Norwegian ecoscarcity methods. According to the Swedish ecoscarcity method the scenario based on concrete is environmentally more negative than scenarios based on asphalt. In contrast, according to the eco-category methods and EPS system, the scenarios based on asphalt are more disadvantageous than those based on concrete. The determining environmental burdens of asphalt pavement are carbon dioxide, sulphur dioxide and nitrogen oxide emissions, dust and energy consumption. The same is true with respect to concrete pavement. The negative impact for concrete is partly due to the high valuation factors for mercury and cadmium according to the Swedish political targets.
The true value of any pavement is determined by factors such as quality, initial cost and cost of upkeep, service life and quality of service life. The choice between pavement types of equivalent design is based not solely on initial cost, but is almost always dependent on subsequent costs and length of service life. Thus, recent information and references on this topics were summarized and are presented here.
When local governments contemplate which pavement type to use, consideration should be given to versatility, installation and maintenance expense, and life-cycle costs. Local governments often must decide between asphalt and concrete when choosing pavement material for streets or other uses. In this report, American City & County asked the National Asphalt Pavement Association and the Portland Cement Association to present their sides of this issue.
Exergy analysis permits accurate measurement of the degradation of matter and energy using a single concept. A macroscopic exergy accounting method is proposed and applied to assess the environmental impact of road covering material manufacturing. Cement concrete and asphalt covers are examined. From the manufacturing process mass balances and exergy analyses conducted primarily by Szargut and his co-workers, the net exergy consumption for each type of paving material is calculated. This exergy consumption broadly reflects the minimum work required to reform the raw materials and restore the environment to its initial state. This minimum work may serve as a thermodynamic measure of the environmental impact of an entire manufacturing process, from the resource drawn from the environment to the finished product. In the two cases under study, the environmental impact depends on the type, thickness and manufacturing process of the paving material. An older technology, such as the manufacture of cement concrete using the wet process, appears disadvantageous, as is the production of asphalt cover which is manufactured during the fall. The proposed exergy indicator permits ranking of the materials according to their overall long-term impact on the environment.
This paper presents delivered energy consumption and intensity projections for the industries included in the industrial sector of the National Energy Modeling System (NEMS). 1 Delivered energy consumption for the industrial sector as a whole is routinely reported in the Annual Energy Outlook, but the detailed projections for each of the groupings within the industrial sector are not generally discussed. The detailed projections in this paper are grouped into three categories: energy-intensive manufacturing sectors, non-intensive manufacturing sectors, and non-manufacturing industries. The results for the three groups are discussed, as well as results for the industries within each group.
We present the results of a study on process energy use of two asphalt-mixing plants. The production process involves the mixing of granite aggregates and bitumen to give asphalt mixtures. The mixtures are widely used as a road-paving material. A large part of the process energy use is for drying and heating the aggregates. Statistical analyses using historical energy-consumption data show a high correlation between specific energy requirements and rainfall level. Field sampling and laboratory investigations indicate that aggregate moisture content and rainfall level are closely related and that aggregate moisture content is a critical determinant of process-energy requirements. Measures for maintaining a low aggregate moisture level, such as isolating aggregate stockpiles from rain, offer great potential for energy savings. We present estimates of these savings, establish process-energy flows, and compare the performances of the two plants.
Argonne National Laboratory has conducted a study to ascertain the relative importance of improved highway materials compared to vehicle energy consumption on US energy consumption. Energy savings through an improved highway infrastructure can occur in at least three ways. First, replacing aged and failing materials with improved and advanced materials can produce energy ``use`` savings. Second, advances in materials science can yield energy efficiency gains in the production of infrastructure materials. Third, using new or improved transportation-infrastructure materials that have longer service life reduces the energy expended in producing replacement materials and installing or repairing facilities. The Argonne study finds that energy savings from highway materials improvements are on the order of 0.1 à 10¹² to 2.1 à 10¹² Btu. This savings is relatively small compared with energy savings from improvements in vehicle fuel economy. Several infrastructure improvement scenarios were examined, with results that were highly dependent on the assumptions. Reducing traffic congestion, particularly in high-traffic-volume locations, produces major energy savings compared with the other scenarios.
Construction materials account for a significant proportion of nonfuel materials flows throughout the industrialized world. Hydraulic (chiefly portland) cement, the binding agent in concrete and most mortars, is an important construction material. Portland cement is made primarily from finely ground clinker, a manufactured intermediate product that is composed predominantly of hydraulically active calcium silicate minerals formed through high‐temperature burning of limestone and other materials in a kiln. This process typically requires approximately 3 to 6 million Btu (3.2 to 6.3 GJ) of energy and 1.7 tons of raw materials (chiefly limestone) per ton (t) of clinker produced and is accompanied by significant emissions of, in particular, carbon dioxide (CO 2 ), but also nitrogen oxides, sulfur oxides, and particulates. The overall level of CO 2 output, about 1 ton/ton clinker, is almost equally contributed by the calcination of limestone and the combustion of fuels and makes the cement industry one of the top two manufacturing industry sources of this greenhouse gas. The enormous demand for cement and the large energy and raw material requirements of its manufacture allow the cement industry to consume a wide variety of waste raw materials and fuels and provide the industry with significant opportunities to symbiotically utilize large quantities of by‐products of other industries.
This article, the second in a two‐part series, summarizes some of the environmental challenges and opportunities facing the cement manufacturing industry. In the companion article, the chemistry, technology, raw materials, and energy requirements of cement manufacture were summarized. Because of the size and scope of the U.S. cement industry, the article relies primarily on data and practices from the United States.
The U.S. steel industry has taken enormous strides over the past decades to reduce its energy consumption; since the end of World War II, the industry has reduced its energy intensity (energy use per shipped ton) by 60 percent. Between 1990 and 1998 alone, intensity has dropped from 20 to 18 million Btu (MBtu) per ton. This figure is projected to decrease to 15 MBtu/ton by 2010 with an asymptotic trend towards 14 MBtu/ton. Domestic shipments are projected to flatten out over the next decade to around 105 million tons which means that total energy consumption will also decrease. Historically, the steel industry has accounted for about 6 percent of U.S. energy consumption. Today, that figure is less than 2 percent and will decrease further to 1.5 percent by 2010. The primary causes for the decrease in energy consumption since WWII are: The use of pellets in the blast furnace and the application of new technology in the ironmaking process to further reduce fuel rates per net ton of hot metal (NTHM); The total replacement of the open hearth process by basic oxygen and electric furnaces; The almost total replacement of ingot casting by continuous casting (which improved yield dramatically and thus reduced the tons of raw steel required per ton of shipments); and The growth of the electric furnace sector of the industry at the expense of hot metal-based processes (which has also stimulated scrap recycling so that about 55 percent of ''new'' steel is now melted from scrap steel). This report focuses on the concept of good practices (i.e., those that are sustainable and can use today's technology). If all the industry could operate on this basis, the additional savings per ton could total 2 MBtu, As further restructuring occurs and the swing from hot metal-based to electric furnace-based production continues, the average consumption will approach the good practice energy per ton. Further savings will accrue through new technology, particularly in the areas of reduced blast furnace fuel rates and reheating efficiency, both of which relate to large tonnages of material.
As a result of the sharp increase in the price of energy during the 1970s and the associated changes in the relative costs of alternative energy resources, all countries need to conserve energy and to replace expensive sources of energy with cheaper ones. The subjects of energy conservation and fuel substitution have therefore assumed increasing importance worldwide. The cement industry is one of the relatively energy-intensive industries with energy-related costs accounting for a major portion of the costs of manufacturing cement. The recent experience of the industrialized countries has shown that energy costs per unit of output of cement could be significantly reduced through a variety of measures ranging from better housekeeping, energy management, and improved monitoring and control systems to more capital-intensive investments in modifications to existing plant and equipment and conversion to more energy-efficient processes. This report aims at a broad presentation of concepts, measures and issues relevant to achieving such improvements in energy efficiency in the cement industry based on experience in both industrialized and developing countries. In so doing, it identifies possible constraints to the successful execution of energy efficiency programs that can be found in many developing countries, and indicates some measures that can be taken at the government, industry and plant levels to stimulate the achievement of increased energy efficiency at the plant level. (Copyright (c) 1983 The International Bank for Reconstruction and Development/The World Bank.)
New and powerful techniques allow the optimisation of materials selection in mechanical design. The methods identify the subset of materials which maximise performance, subject to given design constraints. Until now, “performance” has been interpreted in mechanical or economic terms. But there is an increasing awareness of the environmental penalty which industrialised nations pay to maintain and increase their manufacturing base. This paper examines the possibility of applying the new optimisation techniques to the task of meeting specified design goals while minimising environmental impact.Neue und wirksame Techniken gestatten die Optimierung der Materialauswahl für mechane Konstruktionen. Die Methoden legen eine Teilmengen von Materialien fest, die für vorgegebene Konstruktionsbelastungen eine maximale Leistungsfähigkeit aufweisen. Bisher wurde „Leistungsfähigkeit” in mechanischem oder ökonomischem Sinn interpretiert. Jedoch wird man sich in steigendem Maße des Umweltproblems bewußt, dem die Industrienationen Tribut zahlen müssen, wenn sie ihre Produktionsbasen aufrechterhalten und erweitern wollen. Es wird die Möglichkeit untersucht, neue Optimierungstechniken auf die Aufgabe anzuwenden, spezielle technische Ziele bei minimierter Umweltschädigung zu erreichen.
Copyright ASCE. For personal use only; all rights reserved. References American Association of State Highway and Transportation Officials ͑AASHTO͒. ͑1974͒. Interim guide for design of pavement structures
- Downloaded
Downloaded from ascelibrary.org by TUFTS UNIVERSITY on 12/02/14. Copyright ASCE. For personal use only; all rights reserved. References American Association of State Highway and Transportation Officials ͑AASHTO͒. ͑1974͒. Interim guide for design of pavement structures, Washington, D.C. American Institute of Architects ͑AIA͒. ͑1997͒. Environmental resource guide, Wiley, New York.
Environmental adaptation of con-crete; environmental impact of concrete and asphalt pavements Technical Research Centre of Finland Comparison of environmental implications of asphalt and steel-reinforced pavements
- T Häkkinen
- K Mäkelä
- ͑1996͒
- C Hendrickson
- ͑1998͒
Häkkinen, T., and Mäkelä, K. ͑1996͒. " Environmental adaptation of con-crete; environmental impact of concrete and asphalt pavements. " Technical Research Centre of Finland, Espoo, Finland Horvath, A. and Hendrickson, C. ͑1998͒. " Comparison of environmental implications of asphalt and steel-reinforced pavements. " Transp. Res. Rec. 1626, Transportation Research Board, Washington, D.C. 105– 113.
Environmental Rep. for Trans-Alaska Pipeline Sys-tem Right-of-Way, U.S. Dept. of the Interior Bureau of Land Manage-ment ͑BLM͒ National Crushed Stone Association ͑NCSA͒. ͑1977͒ Flexible pavement cost estimating guide: Inflation/energy effects, worksheets, spec data
- L D Maxin
- ͑2001͒
Maxin, L. D. ͑2001͒. Environmental Rep. for Trans-Alaska Pipeline Sys-tem Right-of-Way, U.S. Dept. of the Interior Bureau of Land Manage-ment ͑BLM͒, Washington, D.C. National Crushed Stone Association ͑NCSA͒. ͑1977͒. " Flexible pavement cost estimating guide: Inflation/energy effects, worksheets, spec data. " NCSA, Alexandria, Va.
Evaluation of expenditures on rural interstate pavements in Kansas
- S A Cross
- R L Parsons
Environmental Rep. for Trans-Alaska Pipeline System Right-of-Way
- L D Maxin