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Assessment of the mechanical and physical characteristics of PET bricks with different aggregates
... Actualmente se está avanzando en la posibilidad de modificar la granulometría de los materiales que componen estos elementos constructivos, para simplificar y economizar su producción (Peisino et al, 2024). ...
Este trabajo fue realizado en municipios de la provincia de Córdoba, en los cuales se relevaron los residuos sólidos urbanos –RSU– de sus vertederos y se realizaron propuestas de reciclado para la fabricación de elementos constructivos. El propósito del trabajo fue que los gobiernos municipales visibilicen la posibilidad de crear nuevos circuitos productivos que mejoren las condiciones ambientales y habitacionales de los sectores de menores recursos a partir del reciclado de residuos. Se elaboró un diagnóstico de los RSU que produce cada municipio, y se realizaron transferencias tecnológicas de elementos constructivos desarrollados en el instituto, que incluyen estos residuos. Se construyeron prototipos demostrativos en cada municipio para motivar a la población a realizar recolección diferenciada de residuos y promover la creación de emprendimientos productivos. Finalmente, se pusieron en marcha emprendimientos productivos, brindando asesoramiento y control de calidad de los productos.
... Studies that are more recent have explored the use of waste materials in construction for sustainable engineering applications. (Peisino et al 2024) evaluated the mechanical performance of PET-based cement mortar using aggregates like sand, construction waste, and polystyrene, achieving a mechanical strength of 2 MPa for bricks with 8 mm-long PET particles, suitable for non-structural social housing applications. (Sarkar and Das 2019) examined the enhancement of compressive strength in red soil and fly ash bricks through graphene reinforcement, achieving significant strength improvement and reducing water absorption in fly ash bricks. ...
This study explores the feasibility and benefits of utilizing plastic waste in the production of construction materials, specifically composite bricks. The escalating accumulation of plastic waste poses significant environmental challenges, which necessitates innovative approaches for recycling and re-utilization to mitigate pollution and reduce landfill use. Our research focuses on the synthesis of bricks by incorporating high-density polyethylene (HDPE) and polystyrene (PS) with sand brick powder, utilizing a compatibilizer (SBS-g-MA) to enhance interfacial adhesion and mechanical integrity. The experimental methodology involved the preparation of composite materials through melt mixing, followed by molding to form brick specimens. These were analyzed for their mechanical properties, including tensile strength, Young’s modulus, and elongation at break, as well as thermal properties such as degradation temperature and crystallization behavior. Results showed that the inclusion of sand brick powder significantly enhances the thermal stability of the composites, as evidenced by the higher degradation temperatures observed. Specifically, the degradation temperature increased from 300.59 °C in pure HDPE/PS blends to 420.39 °C in composites with 7% brick powder, suggesting the formation of a protective barrier against thermal decomposition. Moreover, mechanical testing revealed that composites with up to 7% brick powder exhibited improved tensile strength and Young’s modulus compared to pure polymer blends.
... Additionally, utilizing C&DW and rock processing residues as substrate materials in constructed wetlands shows promising results in treating wastewater, offering environmental benefits, cost savings, and efficient pollutant removal (Kotsia et al., 2024). Furthermore, innovative approaches like using C&DW along with discarded PET plastic bottles in cement mortar formulations demonstrate the potential for creating sustainable building materials for non-structural elements in construction projects (Peisino et al., 2024). ...
Construction and demolition activities are significant contributors to waste generation worldwide. As population growth accelerates globally, the amount of construction and demolition waste (C&DW) will increase proportionally unless proactive measures are implemented. This study analyzes the evolving research landscape on utilizing Building Information Modeling (BIM) technologies to advance sustainable C&DW management practices.
A comprehensive text-mining analysis is conducted on 493 scholarly publications, covering developments from January 2009 to February 2024, using the PRISMA framework. The research objectives are: (i) to identify key themes in the domain of BIM technology for C&DW management using VOSviewer, (ii) to map the temporal evolution of research focus using SciMAT, and (iii) to identify emerging thematic trends.
Co-occurrence analysis reveals three major research themes: (i) the use of digital twins and prefabrication for waste reduction, (ii) integrating environmental impact assessments, and (iii) data-driven decision-making. Strategic diagrams produced by the SciMAT software uncover shifting priorities over the study period, with "reuse and recycling" emerging as motor themes. "Prefabrication" (CIT = 481), "Decision Making" (CIT = 66), "Material Passport" (CIT = 92), and "Digital Twin" (CIT = 44) emerged as high-centrality and transversal themes.
Temporal evolution mapping unveiled the progressive integration of BIM tools, such as (i) digital twins (TLS = 34, OCC = 9) and (ii) prefabrication (TLS = 40, OCC = 14), presenting opportunities to optimize waste reduction. This study offers a robust overview of the field, aiming to inform a diverse audience, including researchers from various disciplines, policymakers, and industry professionals interested in advancing sustainable practices in C&DW management through innovative digital solutions.
The granulometric distribution of the aggregates used in pervious concrete can significantly impact its mechanical and hydraulic properties by modifying granular skeleton and pore distribution. The unit weight increases when single-sized aggregates are combined, which results in improved mechanical properties. In this study, the maximum density methodology was applied to enhance pervious concrete’s mechanical strength by using three narrow-sized basaltic aggregates and their combination. The experimental results showed that the mechanical performance of the samples created with packed aggregates improved compressive strength by up to 81.2% and the energy support impact was higher than 225 J (50% higher than the reference sample) after curing for 28 days. Although the densification of packing aggregates increased, the greatest reduction in porosity was 24.3%. The lowest infiltration rate was 0.43 cm/s, a satisfactory value according to the literature. These findings suggest that the aggregates packing methodology is effective in producing optimized and sustainable pervious concretes.
Plastic and glass can be sorted using machines and recycled into new plastic and glass as opposed to producing them from raw materials. However, contaminated plastic and glass, as well as certain types of plastic and glass, cannot be recycled using traditional methods and must be disposed of in a landfill. Researchers have been looking into these and have tried a variety of solutions to convert this waste into functional products. The development of composite construction materials based on these two materials was identified as a worthy solution. On the other hand, carbon dioxide is emitted during the cement manufacturing process and the use of that cement in the production of construction materials contributes 7% of total global greenhouse gas emissions. Hence, plastic sand/glass composite is environmentally friendly in two ways. It reduces landfill while also replacing the equivalent concrete product, lowering CO2 emissions. This paper examines the literature on the development of such materials, including technology, challenges, quality, and properties. The development of a glass/sand composite to use as a material in the commercial scale production of building materials such as roof and pavement tiles is described based on studies that are available.
The building industry generates millions of tons of construction and demolition waste annually (12 million tons/year are generated in Mexico, of which only 4% is reused or recycled). Concomitantly, the demand for goods and services by the building industry causes significant environmental impacts. On the other hand, plastic waste is also difficult to assimilate into the environment in the short term, and its recovery is of special interest. Therefore, this research focuses on the feasibility of the manufacture of Partition Blocks (essential building element) through the combination of construction and demolition waste (CDW), polyethylene terephthalate (PET) plastic flakes, dust from tire shredding, and residue from the sugar industry (bagasse). The results of this study show that the Partition Blocks made with CDW and PET reach an average compressive strength of 115.003 kgf/cm2 (11.278 MPa) (suitable for structural use according to Mexican regulations); the use of lime enhances the consistency of the mixture of CDW and PET (increases its cohesion and homogeneity); and finally, these Partition Blocks have a cost comparable to the current conventional Partition Blocks made with virgin material, thus, conferring them validity as a feasible recycling option for these residues.
An ever-growing demand for depleted natural resources is one of the significant challenges facing the global asphalt pavement industry in building and maintaining global asphalt pavements. Because plastics are ubiquitous in the global economy, they are the latest in a series of high-profile materials to attract attention. Their low material recovery rates and the environmental impact of current disposal methods pose a threat to plastic recycling. Recycling plastic wastes in asphalt pavement is a possible approach to reducing environmental pressure and the demand for depleted natural resources. Many studies have proposed recycling plastic waste in asphalt pavement using dry- and wet-processed technologies. This review aims to comprehensively evaluate the feasibility of various recycled plastics in asphalt pavement concerning the properties of compatibility, storage stability, microstructure, thermo-rheology, and mechanical performance and to identify challenges and recommendations for the future. This review discusses recent developments and the feasibility of using plastic wastes as modifiers or additives to asphalt binders or asphalt mixtures in dry and wet processes, focusing on different materials from waste streams, how to produce such modified materials, and the characteristics of plastic waste modified asphalt, thus contributing to the sustainable management of resources and production of useful paving materials.
The incorporation of plastic aggregates as a partial replacement of natural aggregates in cementitious materials is interesting in several ways. From a mechanical point of view, the partial substitution of sand with plastic aggregates could improve some properties (e.g., ductility, thoughness). This paper deals with the mechanical strength of mortars containing plastic aggregates as a partial replacement of sand. Part of the volume of sand in cement mortars is substituted with plastic aggregates which originate from WEEE (Waste from Electrical and Electronic Equipment) and consist of a mix of ABS (acrylonitrile-butadiene styrene), HIPS (high impact polystyrene) and PP (Polypropylene), or of monomaterial ABS from WEEE sorting. Three rates of replacement (by volume of sand) were tested: 10%, 15% and 30%. Mechanical tests were performed according to European standard EN196-1. The results show that compressive and flexural strength decrease with rate of replacement, but remain satisfactory for structural purposes. In addition, the density of mortar is reduced with the incorporation of plastic aggregates. The decrease of mechanical strength is mainly due to the weak bond between cement paste and plastic aggregates leading to the increase of porosity. Furthermore, it appears that mortars containing plastic aggregates could present a ductile rupture
Disposal of plastic waste has become a widely discussed issue, due to the potential environmental impact of improper waste disposal. Polyethylene terephthalate (PET) packaging accounted for 44.7% of single-serve beverage packaging in the US in 2021, and 12% of global solid waste. A strategic solution is needed to manage plastic packaging solid waste. Major beverage manufacturers have pledged to reduce their environmental footprint by taking steps towards a sustainable future. The PET bottle has several properties that make it an environmentally friendly choice. The PET bottle has good barrier properties as its single-layer, mono-material composition allows it to be more easily recycled. Compared to glass, the PET bottle is lightweight and has a lower carbon footprint in production and transportation. With modern advancements to decontamination processes in the recycling of post-consumer recycled PET (rPET or PCR), it has become a safe material for reuse as beverage packaging. It has been 30 years since the FDA first began certifying PCR PET production processes as compliant for production of food contact PCR PET, for application within the United States. This article provides an overview of PET bottle-to-bottle recycling and guidance for beverage manufacturers looking to advance goals for sustainability.
The production of plastic wastes is a growing environmental problem in the era of industrialization and economic growth due to the varied applications of polymeric materials. The wastes, which are mainly landfilled pollute land and waste resources due to the toxic and resistant to biodegradation nature of their components. Therefore, innovative approaches to channel plastic wastes away from landfills are imperative. In this mini-review, recycling of plastic wastes to materials useful in the building and construction sector as a viable solution to their environmental accumulation was focused on. Using pre-existent empirical studies, it was established that plastics can be used alone or in combination with other materials at varied percentage compositions to make various building and construction materials. These include bricks, blocks, tiles, asphalt, bitumen, geosynthetics, door panels, insulation materials and cementitious composites. These applications are enhancers to environmental sustainability as they reduce the mining and transport of conventional building and construction materials, which result to atmospheric pollution. It was noted that there was need to commercialize the applications by advancing to better plastic harvesting technologies and cost-effective recycling approaches for wastes with a variety of plastics. Assessing the lifecycle of recycling plastic materials for building and construction in addition to devising regulations to standardize the processes involved was recommended to validate the ability of the advances to enhance sustainability.
The continuous growth of the concrete industry requires an increased quantity of cement and natural aggregates year after year, and it is responsible for a major part of the global CO2 emissions. These aspects led to rigorous research for suitable raw materials. Taking into account that these raw materials must have a sustainable character and also a low impact on environmental pollution, the replacement of the conventional components of concrete by residual waste can lead to these targets. This paper’s aim is to analyze the density, compressive strength and the thermal conductivity of nine concrete compositions with various rates of waste: four mixes with 10%, 20%, 40% and 60% chopped PET bottles aggregates and 10% fly ash as cement partial substitution; a mix with 60% waste polystyrene of 4–8 mm and 10% fly ash; a mix with 20% waste polystyrene of 4–8 mm, 10% waste polystyrene of 0–4 mm and 10% fly ash; a mix with 50% waste polystyrene of 4–8 mm, 20% waste polystyrene of 0–4 mm and 20% fly ash two mixes with 10% fly ash and 10% and 40% waste sawdust, respectively. Using 60% PET aggregates, 60% polystyrene granules of 4–8 mm, or 20% polystyrene of 0–4 mm together with 50% polystyrene of 4–8 mm led to the obtainment of lightweight concrete, with a density lower than 2000 kg/m3. These mixes also registered the best results from a thermal conductivity point of view, after the concrete mix with 40% saw dust. Regarding compressive strength, the mix with 10% PET obtained a result very close to the reference mix, while those with 20% PET, 40% PET, 30% polystyrene, and 10% saw dust, respectively, registered values between 22 MPa and 25 MPa, values appropriate for structural uses.
Cementitious materials cause a great impact on the environment due to the calcination of clinker and the extraction of non-renewable mineral resources. In this work, the replacement of quartz sand from the river by PET sand was evaluated at levels of 10%, 20%, and 30%. Tests were performed in the fresh state through consistency, air retention, density, and incorporated air and in the hardened state for compressive strength, flexural strength, density, capillarity, and water absorption. The results show that PET sand is viable in contents of up to 10%, improving the mechanical properties of the mortar and without compromising its workability and incorporated air properties. Above that level, the loss of properties is very excessive, mainly of workability and incorporated air. The incorporated air of the 30% composition, for example, reaches 24%, an excessive value that impacts the properties of the hardened state, making it impossible to use the material at levels greater than 20%. It is concluded that the use of recycled PET sand is a possibility that contributes to sustainable development, as it reduces the extraction of quartz sand from the river, a non-renewable mineral resource.
Conventionally, in a linear economy, C&D (Construction and Demolition) waste was considered as zero value materials, and, as a result of that, most C&D waste materials ended up in landfills. In recent years, with the increase in the awareness around sustainability and resource management, various countries have started to explore new models to minimize the use of limited resources which are currently overused, mismanaged, or quickly depleting. In this regard, the implementation of CE (Circular Economy) has emerged as a potential model to minimize the negative impact of C&D wastes on the environment. However, there are some challenges hindering a full transition to CE in the construction and demolition sectors. Therefore, this review paper aims to critically scrutinize different aspects of C&D waste and how CE can be integrated into construction projects. Reviewing of the literature revealed that the barriers in the implementation of CE in C&D waste sectors fall in five main domains, namely legal, technical, social, behavioral, and economic aspects. In this context, it was found that policy and governance, permits and specifications, technological limitation, quality and performance, knowledge and information, and, finally, the costs associated with the implementation of CE model at the early stage are the main barriers. In addition to these, from the contractors’ perspective, C&D waste dismantling, segregation, and on-site sorting, transportation, and local recovery processes are the main challenges at the start point for small-scale companies. To address the abovementioned challenges, and also to minimize the ambiguity of resulting outcomes by implementing CE in C&D waste sectors, there is an urgent need to introduce a global framework and a practicable pathway to allow companies to implement such models, regardless of their scale and location. Additionally, in this paper, recommendations on the direction for areas of future studies for a reduction in the environmental impacts have been provided. To structure an effective model approach, the future direction should be more focused on dismantling practices, hazardous material handling, quality control on waste acceptance, and material recovery processes, as well as a incentivization mechanism to promote ecological, economic, and social benefits of the CE for C&D sectors.
Construction and demolition wastes (CDW) are generated at a large scale and have a diversified potential in the construction sector. The replacement of natural aggregates (NA) with CDW recycled aggregates (RA) in construction materials, such as mortars, has several environmental benefits, such as the reduction in the natural resources used in these products and simultaneous prevention of waste landfill. Complementarily, CDW have the potential to capture CO2 since some of their components may carbonate, which also contributes to a decrease in global warming potential. The main objective of this research is to evaluate the influence of the exposure of CDW RA to CO2 produced in cement factories and its effect on mortars. Several mortars were developed with a volumetric ratio of 1:4 (cement: aggregate), with NA (reference mortar), CDW RA and CDW RA exposed to high levels of CO2 (CRA). The two types of waste aggregate were incorporated, replacing NA at 50% and 100% (in volume). The mortars with NA and non-carbonated RA and CRA from CDW were analysed, accounting for their performance in the fresh and hardened states in terms of workability, mechanical behaviour and water absorption by capillarity. It was concluded that mortars with CDW (both CRA and non-carbonated RA) generally present a good performance for non-structural purposes, although they suffer a moderate decrease in mechanical performance when NA is replaced with RA. Additionally, small improvements were found in the performance of the aggregates and mortars with CRA subjected to a CO2 curing for a short period (5 h), while a long carbonation period (5 d) led to a decrease in performance, contrary to the results obtained in the literature that indicate a significant increase in such characteristics. This difference could be because the literature focused on made-in-laboratory CDW aggregates, while, in this research, the wastes came from real demolition activities, and were thus older and more heterogeneous.
Recycled aggregates present a varied mineralogical composition and the grading of these particulates over their particle size distribution influence the aggregate properties as well as those of the composites that they form. This study proposed a comparative investigation of the influence of the particle size distribution of fine aggregates from two different origins, namely, natural crushed stone and construction and demolition waste (CDW). Three particle size distributions were defined, so that each aggregate had its fineness modulus (FM) ranked in the granulometric ranges, following the NBR 7211 Brazilian standard. The following tests were carried out: consistency, bulk density in the fresh state, compression strength, absorption (by immersion and capillarity), dimensional and mass variation. The results showed that the aggregate mineralogical composition impacted the mortar properties and that, when analyzed along with the particle size distribution, CDW showed different and varied behavior as a function of its particle size and distribution. Another finding was that mortars produced with CDW aggregate with granulometry below the lower optimal zone (FM<2.20) presented reduced mechanical and physical performance. Therefore, it was concluded that CDW aggregates should not be included in the same standards as conventional aggregates regarding the fine aggregate granulometric composition.
The ever-growing consumption and improper disposal of non-biodegradable plastic
wastes is bringing worrisome perspectives on the lack of suitable environmentally correct solutions.
Consequently, an increasing interest in the circular economy and sustainable techniques is being
raised regarding the management of these wastes. The present work proposes an eco-friendly
solution for the huge amount of discarded polyethylene terephthalate (PET) wastes by addition
into soil-cement bricks. Room temperature molded 300 � 150 � 70 mm bricks were fabricated with
mixtures of clay soil and ordinary Portland cement added with up to 30 wt.% of PET waste particles.
Granulometric analysis of soil indicated it as sandy and adequate for brick fabrication. As for the PET
particles, they can be considered non-plastic and sandy. The Atterberg consistency limits indicated
that addition of 20 wt.% PET waste gives the highest plasticity limit of 17.3%; moreover, with
PET waste addition there was an increase in the optimum moisture content for the compaction and
decrease in specific weight. Standard tests showed an increase in compressive strength from 0.83 MPa
for the plain soil-cement to 1.80 MPa for the 20 wt.% PET-added bricks. As for water absorption, all
bricks displayed values between 15% and 16% that attended the standards and might be considered
an alternative for non-structural applications, such as wall closures in building construction.
Plastic waste is spread at an unprecedented speed due to the rapid use of domestic and industrial plastic items. The environmental pollution resulting from the continued disposal of plastic wastes in landfills has not only created land problems but has also heightened the pollution of marine resources. This paper aims to review and investigate the feasibility of utilizing plastic waste in making construction bricks. The use of plastic waste in making the sand-plastic bricks will enhance the protection of the environment from the effects of plastic waste that normally takes several millennials to degrade. Thermostatic plastic waste; that is, those polymers whose recycling may not affect the environment, including polyethylene (PE) and polyethylene terephthalate (PET), is found to implore lightweight, durable, cost-effective, and low thermal conductor bricks. Compressive strength (CS) and water absorption tests are found as the key test methods for measuring the effectiveness of high-volume content of plastic waste in bricks. Notably, a high percentage of plastic waste in proportion to sand is found to improve the compressive strength of the bricks besides allowing negligible water to seep through.
In this present study, the effectiveness of expanded polystyrene (EPS) waste used as 20, 40 and 60% fine sand replacement in development of lightweight cement composite was evaluated. The cement mortar was strengthened by 10% low cost latex paint emulsion as an alternative to the more expensive polymer admixtures. Six different mix designs were produced and tested for com-pressive and split tensile strength according to BS EN standards. Scanning electron microscope (SEM) analysis was also conducted to analysis the micrograph of the samples. It was observed that as the EPS content, latex paint polymer admixture and curing days were increased, marginal increment in compressive strength was obtained. However , EPS fines were most effective in improving the split strength while latex paint admixture had comparatively less part to play in the strength development. The micro-graph images showed that the EPS fines were uniformly distributed within the microstructure and the latex paint developed polymer films. These mechanisms coupled with the cement hydrate products were responsible for the enhanced strength observed in the samples.
The vision of this study is geared towards the exploitation of waste plastic bottle use in construction. This review paper is centers on the recycling of waste plastic bottles as a construction material as an effort to help solve the housing deficit in most developing countries including Ghana and to save the depletion of natural resources construction materials. In Ghana, plastic wastes are discarded randomly after usage, hence scatter around in cities, choking drains, and end up threatening our ecosystem. These predominant effects from the plastic wastes have necessitated the need for countries precisely developing countries including Ghana to seek more sustainable methods to reduce the drastic amount of plastic wastes in the environment. In view of the above, this paper focused on the recycling of waste plastic bottles as a construction material as an effort to solve the housing deficit in most developing countries including Ghana and to save the depletion of natural resources construction materials (stones and sand) are very much critical. In the reviews, an effort has been made to utilize the waster plastic bottles in construction by filling the bottles with soil, sand, solid waste materials as brick or block bounded with mortar as a masonry wall or the filled bottles are used as a substitute for the production of the masonry unit production. In summary, it was concluded based on varying test result that: (1) Plastic waste bottles are cheaper to acquire than most conventional construction materials and as such concrete or brick containing any amount of plastic bottle is noted to reduce the total quantities of conventional materials required, thereby reducing the cost as well. (2) The use of plastic waste bottles in construction contributes to environmental friendliness and energy savings since buildings with walls constructed of plastic bottles maintains room temperatures and contribute to energy saving and the cost of providing an artificial thermal control system. Doi: 10.28991/cej-2020-03091616 Full Text: PDF
The incorporation of a recycled concrete aggregate (RCA) as a replacement of natural aggregates (NA) in road construction has been the subject of recent research. This tendency promotes sustainability, but its use depends mainly on the final product's properties, such as chemical stability. This study evaluates the physical and chemical properties of RCAs from two different sources in comparison with the performance of NA. One RCA was obtained from the demolition of a building (recycled concrete aggregate of a building-RCAB) and another RCA from the rehabilitation of a Portland cement concrete pavement (recycled concrete aggregate from a pavement-RCAP). Characterization techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), UV spectroscopy, and atomic absorption spectrometry were used to evaluate the RCAs' coarse fractions for chemical potential effects on asphalt mixtures. NA was replaced with RCA at 15%, 30%, and 45% for each size of the coarse fractions (retained 19.0, 12.5, 9.5, and 4.75 sieves in mm). The mineralogical characterization results indicated the presence of quartz (SiO 2) and calcite (CaCO 3) as the most significant constituents of the aggregates. XFR showed that RCAs have lower levels of CaO and Al 2 O 3 concerning NA. Potential reactions in asphalt mixtures by nitration, sulfonation, amination of organic compounds, and reactions by alkaline activation in the aggregates were discarded due to the minimum concentration of components such as NO 2 , (-SO 3 H), (-SO 2 Cl), and (Na) in the aggregates. Finally, this research concludes that studied RCAs might be used as replacements of coarse aggregate in asphalt mixtures since chemical properties do not affect the overall chemical stability of the asphalt mixture.
A huge amount of expanded polystyrene (EPS) and PET plastics are produced every year all around the world. However, if not treated properly, after their consumption, EPS and PET caused numerous environmental problems. Therefore, the utilization of these wastes in concrete production can contribute to the sustainability of construction materials. This experimental study aims to investigate the behavior and properties of pervious concrete incorporating both EPS aggregates and waste PET fibers. A total of ten concrete mixtures were designed with different percentages of PET fibers and the same amount of EPS content. The investigated parameters included: abrasion resistance, dry density, compression as well as flexural strength, porosity ratio and water permeability coefficient. From the results obtained in this study, it has been shown that the proposed mixes are reliable to use in the construction field. The compressive strength, abrasion resistance and density decreased by incorporating EPS and PET fibers. However, the flexural strength increased by using PET fibers up to 1% in volume. On the other hand, the porosity ratio and the water permeability coefficient increased through the addition of PET fiber. The empirical models among different properties were also provided. This experimental study can be contributed to promote sustainable construction materials as mixtures contained a considerable amount of waste materials.
This paper investigates the influence of aggregates grading and shape in coating mortar performance, both fresh and hardened stages (mechanical properties and durability). Eight samples of mortar were prepared, using Portland cement type CP II-E-32 (corresponding to American cement: I (SM) ASTM - C 595), natural quartzous aggregate, crushed gneiss artificial aggregate, hydrated lime and water. It was analyzed the packaging of aggregates by determining their grading curves, unitary gravity and void ratio. Aggregates shape was analyzed through images obtained with a stereoscopic magnifying. Regarding coating mortar properties, mechanical properties and durability were analyzed as an aggregates shape function and its granulometric distribution through evaluation of consistency, fresh and hardened state density, air entrained content, water absorption by immersion and porosity, pull-off strength, compressive strength - fc, flexural strength - ft and elasticity modulus - Ed and assessing fissurability. In general, results showed that the particle size curve and the type of aggregate influence significantly the properties analyzed and should be considered during dosing process of coating Portland cement mortar specification, hence many standards to concrete may not be suitable for these composite parts.
Bangladesh is 10th among the major plastic waste contributor countries of the globe. Throughout the world, plastic waste disposal is a major concern since it is being nonbiodegradable in nature and hazardous, because of its potential harmful effect on human health and to the environment. Various studies have shown that waste PET (polyethylene terephthalate) plastic bottle filled with sand or other inorganic materials can serve as a useful building material where plastic waste management or recycling process is not very effective and particularly, in low-income communities. Plastic brick use in existing Rohingya refugee camp and newly proposed displacement camp in the coast island—Bhasan Char—as construction material to build new shelters, can be a sustainable use and management of country’s plastic waste, and a feasible solution against the shelter issues of Rohingya people. The vulnerability due to heavy wind, monsoon rains, cyclones, and the gaps and lack in funding to build new rigid and safe shelters can be effectively mitigated by using this low-cost, environment-friendly plastic brick as building block in refugee camps.
Today, recycling of construction and demolition waste (C&DW) by plants is a reasonable alternative to the existing unsustainable disposal methods such as landfilling and fly tipping. Therefore, this study aims to report current management issues of these plants in the literature. As a result, it was seen that these management issues investigated in past researches can be classified under four main groups such as economics, environment, location, and administration. Their pros and cons were also revealed in a covering manner. As these issues have not been addressed together up to date and each one of them has been investigated separately, the present study is the first attempt to give a full picture of management issues of the recycling plants. Thus, it can fill the gap in the literature. As a research implication, this study may help researchers who will investigate C&DW recycling plants from different perspectives. In terms of the practical implication, it may attract attention of industrial practitioners and entrepreneurs in public authorities and the private sector to benefit from such wastes through plants. Finally, as a social implication, better management of C&DW recycling plants can save and enhance the sustainability of the overall environment and affect society positively.
The building industry is facing the challenge of satisfying a growing demand for housing spaces that can be mitigated by
the use of construction materials manufactured with industrial by-products that allow the production of low-cost housing with
a low environmental impact. In this research, an alternative building system to manufacture lightweight masonry blocks with
polyethylene terephthalate (PET) bottles and fiber-reinforced panels using binary mixture (Portland cement and fly ash), was
studied. This building system was tested under compressive and flexural loads until failure. The average design compressive
strengths of concrete blocks for w/c ratios of 0.78 and 1.1 were fp* = 1.9 and 1.2 MPa respectively, these results were similar to
those typical masonry in accordance with the design and construction standards. On the other hand, the flexural strength, the
modulus of elasticity and the stiffness on mid span of the fiber-reinforced concrete panels were improved with adding 20% of
fly ash to both w/c ratios, mainly at 120 days. The experimental results obtained show that those building elements are viable
alternatives with mechanical properties comparable to traditional building systems, besides the reduction of the environmental
impact due to the incorporation of industrial waste materials.
In general, the quantity of plastics of all types consumed annually all over the world has been growing in a phenomenal way. The manufacturing processes, service industries and municipal solid wastes (MSW) generate numerous waste plastic materials. The increasing awareness about the environment has tremendously contributed to the concerns related with disposal of the generated wastes. It is believed that the management of solid waste is one of the major environmental concerns in the world. Due to limited space on landfills and increasing costs of plastics, utilization of waste plastics has become an attractive alternative for disposal. This paper provides a summary of experimental efforts on the utilization of poly(ethylene terephthalate) (PET) in civil engineering projects, mainly in road pavement, cements and concretes. Presented data indicate that use of waste PET for modification of asphalt, cement and concretes improved their selected properties, which makes economical this approach. Furthermore, using of waste PET in building materials reduce usage of new polymeric materials, which has significant effect on environment pollution (e.g. emission of carbon dioxide, waste disposal problems, etc.) Index Terms—Bitumen, building materials, concrete, PET, recycling.
Substantial growth in the utilization of plastic has increased tremendously in recent years, which may lead to the disposal of tons of plastic waste into the environment. Recycling of such plastic waste to utilize as a substitute aggregate in the construction materials like bricks, mortar, and concrete was considered as one of the feasible solutions in plastic waste management. It additionally aids to reduce the mining of minerals for raw materials in the construction industry, which might enhance sustainability. We must comprehend the strength, weakness, opportunities and threat (SWOT Analysis) of plastic-induced building material with regard to their strength features and socio-economic benefit in order to use plastic waste as an aggregate commercially. Several works have been performed or are underway to evaluate the strength characteristics of construction material that includes various types of plastic waste as an aggregate. This paper presents a summary of such research works by examining their physical, mechanical, and durability properties along with resistance to alkali conditions and Fire resistance was discussed in separate sections. Along with that, the study analyzes the relationship between the different strength properties and is represented graphically. The review analysis reveals that the different authors achieved different results, but most of the authors achieved standard requirements, while some authors do not achieve the standard requirements. The review concludes that the utilization of plastic waste in minimal quantities (10–20%) helps to achieve the desired results and recommends several research points, which helps, in future, research to commercialize these plastic-induced construction materials.
The study attempts to investigate the economic and environmental feasibility of linking the plastic waste
recycling industry with the construction sector as a circular economy model (CE), particularly for Egypt. The
result figured out that adopting the CE approach has several substantial environmental and economic benefits. It
can turn plastic waste into eco-friendly and affordable building materials besides aligning with sustainable
development goals (SDGs). The study contributes to raising local awareness about the potential of waste recy�cling. Moreover, promoting local stakeholders to widely apply the CE model in the construction and recycling
plastic waste industry for a better sustainable environment
Plastic trash has become a huge environmental concern due to the large volumes produced, inflicting substantial harm to both the ecology and its inhabitants. This hazard has a huge impact on the maritime environment. The plastic garbage produced on land eventually makes its way to water bodies, where it has negative consequences such as floods and marine animal poisoning. When aquatic animals like fish consume this plastic garbage, it is detrimental to human health as well. To determine the most efficient method for managing these wastes and enhancing the sustainability of our ecosystem, this review discloses several processing strategies for recycling plastic trash into new goods with a specific focus on construction and building. It has been discovered that recycling plastic trash for building purposes would significantly improve climate sustainability along with serving as a reliable source material in construction supplies. This study shows that employing recycled plastic waste, as a component in cementitious composites is the most advantageous because it may be used to replace all of the composite's solid components. The pursued qualitative analysis of various plastic waste management techniques, focusing on the most significant features, reveals that newer methodologies are more effective in terms of environment and sustainability, but are not economical. Finally, limitations and directions of use are also listed to throw light on the recycling of circular economy.
Plastic waste management represents a significant problem worldwide, but also, an opportunity for construction materials development. This manuscript explores plastic composite trends, emphasizing thermal and mechanical features. Data obtained from literature over 88 plastic composites were classified into six filler-based categories, 78% presented mechanical data, whereas only 40% provided thermal characterization. The explored features summarize thermal conductivity range values from 0.02 to 2.23 W/(m·K) and Compression Strength between 0.1 and 158 MPa within the recycled plastic composites repository with densities from 50 to 2100 kg/m3, similar to those considered conventionally a feasible possibility to reduce energy demand through low-energy architectural envelopes.
With increasing usage of polyethylene terephthalate (PET) wastes polluting the oceans and environment, the recycling of PET wastes has become a crucial issue to be overcome. In this article, a review of the different technologies that have been developed to recycle PET wastes and common routes for recycled PET (rPET) is presented. The impacts of varied recycling technologies on the properties of rPET are also discussed herein. The review also focuses on the recovered products by each of the technology and their uses that have been reincorporated into new applications for example, from plastic bottle wastes to 3D scaffolds for biomedical application. Different recycling technologies such as reactive extrusion, chemical recycling and dissolution/precipitation exhibit specific properties due to the influence of the different concepts from one technology to another. A new trend called electrospinning of rPET to produce nanofibers has also garnered attention to be used for different applications. This article will first introduce the recycling technologies concept, and then the properties of the recovered product will be discussed and finally, we will focus on the applications of rPET produced from each of the technologies in various fields such as construction, textile, filtration, and biomedical applications.
This study contributes to the understanding of the effect of recycled high-density polyethylene (HDPE) aggregates on the compressive mechanical properties and stress–strain relationship of cement mortar. HDPE aggregates recycled from plastic wastes were used to substitute natural sand in cement mortar, thereby offering a novel approach to plastic waste management and reducing the overconsumption of limited natural resources. The compressive behavior of cement mortar containing 0%–100% HDPE contents was investigated after 7 and 28 days. The experimental results showed the negative effect of HDPE aggregates on the modulus of elasticity (Ec) and compressive strength (fcmax) of cement mortar. However, the substitution of natural sand with HDPE aggregates reduced the density and increased the axial deformation capability of cement mortar, particularly when the volumetric substitution percentage exceeded 50%. The Ec, peak strain, and ultimate strain exhibited strong relationships with the substitution percentage and fcmax. Furthermore, the proposed empirical relationships between the parameters were evaluated. Finally, stress–strain models of HDPE mortars were established based on the available models for concrete. The proposed models appropriately predicted the complete stress–strain curves of cement mortars containing various amounts of plastic content.
Blended cements having partial replacement of fly ash (FA) and granulated blast furnace slag (GBFS) with Ordinary Portland Cement (OPC) have proven to be more sustainable cements with several ecological benefits, increased performance and durability aspects compared to plain OPC. In this study, three blended cements, namely Portland Pozzolana Cement (OPC + FA), Portland Slag Cement (OPC + GBFS) and Composite Cement (OPC + FA + GBFS) are examined. Three Particle Packing Models (PPM) viz. Modified Toufar Model (MTM), J D Dewar model (JDD) and Compressible Packing Model (CPM) are considered to evaluate the gradation of fine aggregates used in designing the mortars and are compared with the mortars designed as per IS 650:2008. The theoretical maximum packing density values obtained based on MTM, JDD and CPM models are 0.681, 0.674 and 0.668 respectively, while the experimental packing density values are 0.617, 0.626 and 0.642 respectively. The compressive strength of Composite Cement (CC), Portland Slag Cement (PSC) and Portland Pozzolana Cement (PPC) mortars exhibited a delay in gain of strength compared to OPC mortars. The mortar samples prepared using CPM model, showed an average increase in compressive strength of 20.71% at 7 days, 12.26% at 28 days and 10.29% at 90 days compared to samples designed using IS 650:2008. Similar trend was observed from MTM and JDD mortar samples also with strength of mortars varying as CPM > MTM > JDD > IS 650. This shows that particle packing models are useful in overcoming the delay in early strength of blended cements due to slow pozzolanic reaction. The hydrated phases of cement and microstructure is examined using Scanning Electron Microscopy and X-Ray Diffraction.
Plastic waste accumulation in the environment due to huge volumes of plastic waste produced daily with no effective disposal method and waste management have raised public awareness to look for an alternative to replace the current disposal techniques. Waste utilisation or plastic recycling has been regarded as an excellent method to reduce the abundant amount of plastic waste as well as minimising the environmental impacts. In this article, a total of 163 previous studies between 2012 and 2021 had been reviewed to discuss the utilisation of different types of plastic waste as aggregate in construction materials. This paper evaluates on the use of plastic as aggregate in terms of the physical, mechanical and durability properties of the construction materials as well as the environmental and cost analyses. It was found that the mechanical and durability properties of produced materials were altered after the addition of plastic as aggregates; however, the materials are still fulfilling the requirement of construction materials. Besides, a general SWOT analysis to highlight the advantages and disadvantages of plastic waste utilisation was also conducted.
In this paper, the use of plastic wastes as the only binding material to develop a cemented construction material, PlasticWasteCrete (PWC), was investigated. Two types of plastic waste (high density polyethylene (HDPE), low density polyethylene (LDPE)) are blended (HDPE/LDPE blend ratio: 50/50) and then melted at a temperature of 250°C to develop the binding phase of the PWC. Subsequently, the melted plastic is mixed with mineral aggregates (sand, gravel) in two plastic contents (50% and 60%) to prepare the PWC samples. Then, the compressive and split tensile strength, stress–strain behavior, microstructure, density and water absorption ability of the PWC samples cured at different times (1, 3, 7, 28 days) are evaluated. The results of this study show the feasibility of using melted plastics as the only binder to develop a building material. From the mercury intrusion porosimetry (MIP) test and Imagej analysis, the PWC with 50% plastic content (PWC50) was found to have more voids and coarser pore structure than that with 60% plastic content (PWC60). These MIP results were also confirmed by the larger capillary pores and higher rate of absorption for PWC50 when compared to PWC60. These results were found to be in line with the strength tests for which the PWC60 with less porosity has higher strength in compression and tension than PWC50. Regardless of age and plastic waste content, the compressive strength of PWC was found to be higher than 10 MPa, which somehow exhibit interesting mechanical strength behaviour with ductile deformation and interesting post peak strength capable of supporting loads after failure. The density was found to decrease with the increase of plastic content, and the average density was close to 2 g/cm³, considered as lightweight material. The findings of this study are encouraging and place this PWC as a promising candidate for producing construction materials while diminishing the amount of plastic waste to be managed and the associated environmental issues as well as contributing to generate additional revenues.
Polyethylene terephthalate (PET) plastic and construction and demolition (C&D) wastes contribute to a substantial fraction of the annual landfilling waste composition of the world. Substituting traditional road construction materials with PET/C&D blends is a sustainable solution for the increasing landfilling requirement and increasing demand for the natural quarry aggregates. This study evaluates the main geotechnical parameters of the geopolymer-stabilized blends comprising of two main C&D types, namely recycled concrete aggregate (RCA) and crushed brick (CB), in blends with 5% PET fragments (% by mass). 10%Fly ash (FA), 10%Slag (S) and 5%FA + 5%S were used as the precursors at a fixed liquid activator to precursor ratio of 0.4, and the alkaline activator for the geopolymer solution was comprised of 30:70 ratio of liquid NaOH:Na2SiO3 solution. Strength and stiffness characteristics of the stabilized blends were evaluated by unconfined compressive strength (UCS) tests. The resilient modulus (MR) values of the geopolymer-stabilized blends under different cyclic axial stresses and confining stresses were assessed by repeated load triaxial (RLT) tests. Bulk stress and three-parameter model parameters were determined from the RLT test data to predict the variation of MR of the geopolymer-stabilized PET/C&D blends. All the geopolymer-stabilized blends using 5%FA + 5%S and 10%S as precursors satisfied the minimum UCS limit of the granular materials for light traffic road bases/subbases. Geopolymer-stabilized PET/C&D was identified as a potential, sustainable option for the stabilization of upcoming road bases/subbases.
Conventional methods for recycling demolition concrete and plastic waste do not allow recycling of 100% demolished concrete or large volumes of plastic waste. Furthermore, fresh raw materials for concrete manufacturing are still required, while it is projected that they will soon be in short supply due to ever growing consumption. This study focuses on producing a stabilized construction material with better mechanical strength than traditional concrete. A novel method for recycling demolished concrete and plastic waste by compacting concrete and plastic powders under various pressures and temperatures is proposed. The effects of forming conditions on the bending strength of the compacted plastic–concrete (CPC) are analyzed. Furthermore, the water absorption ability and micro-structure of the CPC are also determined. The experimental results confirm the feasibility of CPC and show promising aspects of CPC related to recycling both types of waste in concrete applications, achieving a closed loop for concrete recycling and a high-volume plastic recycling ratio. SEM results showed that the hot-pressing method ensures a good fusion between concrete and plastic particles. Almost all the specimens formed under different conditions possessed a superior bending strength than traditional concrete, and its strength remains stable with up to 75% plastic composition in the specimen. Therefore, the proposed method reveals the feasibility of large-scale plastics recycling in construction, and makes the CPC competitive with other construction materials.
Plastic is utilized in day today life at present almost 56 lakhs ton of plastic waste delivered in India every year. Plastic are all things considered non-degradable in this manner, they may be take several years to decay. This is a result of the intermolecular bonds that set up plastic, whose structure protect that the plastic neither expend nor separate. As home grown blend assets have gotten exhausted in light of unnecessary call for underway industry & the measure of arranged waste fabric continues developing, analysts are investigating the utilization of elective materials which exact save natural sources & store the environmental factors. In this examine, utilization of molten plastic waste as complete substitution of cement & broken glasses as partial substitution of mixture with nice river s& for the manufacturing of building production enter inclusive of roof tile, ground tile & hollow plastic block is a partial way to environmental & ecological troubles. Quality manipulate check of samples of prepared fabric are carried out &as compared with the standard material specification. This investigation took a gander at the possibility of waste glass consideration as fractional FA substitution frameworks. Properties of cement fusing waste glass as halfway replacement for FA measures of 15% were researched. Here the excellent residences of asphalt squares concerning squander plastics & the arrangement considerations for black-top square joining waste plastic sacks is included. It could be a shelter to current society & situation. The essential point is to use the plastic nature being developed fields with limited additions. It will be obviously a cost reasonable & can be applied in different structures.
The rapid growth in the construction industry and the resulting environmental issues due to improper waste management leads to the formation of new construction materials from waste and its residue. This paper is a review of different research approaches that employs waste materials mixed with fillers as construction materials. A refined analysis of construction materials derived from plastic waste in concrete along with sand, clay, sawdust, rice husk, and other fillers are detailed. The different processes involved in the development of materials along with their mechanical behaviour are being discussed. The application of different coupling agents along with plastic waste and fillers which indicates its future applications as a viable material in the construction industry are also explained in detail.
This article presents testing results of cement mortars, in which Composite Lightweight Aggregates (CLA) obtained in laboratory conditions substitutes a part of natural aggregates. The new aggregates are sustainable products obtained by using 100% waste by-products: PET flakes and sewage sludge fly ash (ssFA) streams or siliceous fly ash (FA). The level of natural aggregate replacement by CLAs in mortars was 10% and 25% by vol. The purpose of the research was to assess the physicochemical properties of fresh and hardened mortars in the context of the quality assessment of two methods of producing CLAs and the type of fly ash used as their integral components. Surface modification of PET using both types of fly ash improves the useable properties of the obtained mortars compared to mortar using unmodified PET. In case of CLA aggregate based on PET and FA, no symptoms of depolymerization of polyethylene terephthalate were observed in the presence of alkali from cement paste. In case of mechanical properties modelled with CLA composite, an increase in compressive or flexural strength has been observed due to the possibility of lowering the w/c ratio in CLAs mixtures without loss of workability. Replacing only a small part of the natural aggregate with CLA aggregate allows for a double ecological aspect: saving of natural resources and full management of problematic plastic and mineral waste. Cement composites with composite lightweight aggregates may be ecosolution for a number of applications for building engineering like ordinary concrete, small pre-cast or modulus concrete.
Current practice of recycled waste plastics includes 7 major types: polyethylene terephthalate (PETE), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and others such as acrylonitrile butadiene styrene (ABS), ethylene vinyl acetate (EVA), polycarbonate (PC), and polyurethane (PU). This paper provides a comprehensive and in-depth literature review on the feasibility and the state-of-art repurposing waste plastics into cleaner asphalt pavement materials. Optimum dosage of waste plastics should be identified based on appropriate engineering performance parameters such as viscosity of asphalt, and rutting, fatigue cracking, thermal cracking, and moisture resistance of asphalt mixtures. If the appropriate amount of plastic is not determined, adverse impacts on the performance of the pavement could occur. Plastic wastes are incorporated into asphalt mixes by the dry (aggregate substitute) or wet (binder modifier, extender, or substitute) methods. In general, the incorporation of plastic wastes into asphalt mixes showed improvements in performance parameters such as stiffness, and rutting and fatigue resistance. However, HDPE, PVC, LDPE, PP, and PS yielded conflicting performance measures. Overall, the capability of recycling waste plastics into asphalt mixes would minimize landfilling, reduce dependence on nonrenewable resources, and diversify asphalt pavement building options. Additional research is needed to fully understand the effects of various plastics on the performance of the pavement, and potential environmental and economic impacts this process could implicate. Another area where further study is needed are methods to improve the compatibilization between plastic and asphalt.
Although several reports can be found in the literature about the recycling of plastic materials, only a few focus on recovering and molding them in a new process. Plastic material blends can be fabricated using several techniques, which allows the molding of a compound adaptable to each needed performance. This fact favors the recycling by allowing the use of mixed wastes without major processes, avoiding expensive treatments. This research work analyzes the mechanical properties of a material conformed by 100% recycled plastics: polyethylene terephthalate and low-/high-density polyethylene without previous separation or washing and drying pretreatments. Its macro and microscopic structure was studied and described, and formulations of different compound rates were analyzed. Mechanical resistance was around 60% of a material composed of virgin materials in compressive, flexural, and tensile strength tests. Its potential application to building components manufacture is analyzed.
Nowadays, the Polyethylene Terephthalate (PET) bottle, which is a post-consumer product, has generated a strong interest in the environmental consequences that surround it, and a suitable alternative is to incorporate it in mortar and concrete. Therefore, the aim of this research was to evaluate rendering mortars based on Portland cement/hydrated lime produced with PET bottle waste, used to partially replace 2.5%, 5%, 10%, 15% and 20% (by volume) of the fine aggregate in order to investigate the effectiveness and the improvement of these materials. The experimental program was performed in the fresh and hardened states, to determine flowability, fresh and hardened densities, air content, apparent porosity, water absorption by immersion, water retention, water absorption by capillarity, drying, water vapor permeability, ultrasonic wave velocity, and dynamic modulus of elasticity. Also, scanning electron microscopy (SEM) was performed. Generally, the results showed that the incorporation of PET significantly changed some properties, as verified by statistical analysis. Remarkable results from the incorporation of PET into rendering mortars based on Portland cement/hydrated lime are: close to 90% similarity of water retention between the mixtures, water absorption due to capillarity of M2.5 at 1.89 kg/(m²·min1/2), drying of the M15 specimen at 5.85 kg/m², water vapor permeability of the M20 at 41.15 (ng/(m·s·Pa)) and the dynamic modulus of elasticity of M2.5 at 3.57 GPa. These replacements showed the possibility of mitigating the environmental impacts that the PET bottle life cycle can have and the extraction of the fine aggregate, promoting another possibility of disposal for this waste.
This study was conducted to assess the performance of cement stabilized polyethylene terephthalate (PET) blends with construction and demolition (C&D) waste, namely recycled concrete aggregate (RCA) and crushed brick (CB), as a pavement construction material. A suite of basic characterization tests was undertaken on 3% and 5% PET blends (by mass) with RCA and CB stabilized with 3% cement. The material strength evaluation of the PET blends were undertaken using unconfined compressive strength (UCS) test and the secant modulus results of the blends were also analyzed. Moreover, the resilient moduli (MR) characteristics were evaluated by repeated load triaxial (RLT) test while the flexural strength and the fatigue life of the blends were evaluated by flexural beam tests. UCS results of the cement stabilized PET blends of RCA and CB satisfied the minimum requirement for 7 days of curing samples. Adding PET decreased the MR values of the C&D waste materials, whilst CB showed higher MR values than RCA. PET blends with CB showed high flexural modulus and fatigue life than PET blends with RCA. The cement-stabilized blends of 5% PET with RCA and CB were found to have physical and strength properties which comply with road authority requirements for pavement base/subbase construction.
The rapid growth in plastic and demolition wastes generation by municipal and commercial industries is a significant challenge to developed and developing countries. The substitution of traditional construction materials with recycled materials is a sustainable solution which mitigates landfilling concerns and reduces the need for virgin quarry materials. In this research, an evaluation of the geotechnical and geo-environmental properties of Polyethylene terephthalate (PET) plastic waste and its blends, with two major constituents of construction and demolition (C&D) waste materials was undertaken. Recycled concrete aggregate (RCA) and crushed brick (CB) were blended with 3% and 5% of PET, and the geotechnical properties of six PET blends were evaluated in the laboratory. The experimental programme included particle size distribution, particle density, sieve analysis, flakiness index, Los Angeles abrasion, water absorption, modified Proctor compaction, hydraulic conductivity, and California bearing ratio (CBR) tests. In addition, the response of the PET blends under repeated dynamic loading conditions was investigated using repeated load triaxial (RLT) tests. CBR results of all six PET blends were higher than the minimum CBR requirements for usage as a subbase material. The RLT testing results indicated that PET blends with RCA and CB performed satisfactorily at 98% maximum dry density and at their optimum moisture contents under modified Proctor compaction effort. Furthermore, a geo-environmental evaluation of the PET blends was undertaken which consisted of determination of organic matter content, pH value, total/leachate concentration of the recycled materials for a range of contaminant constituents and the results were compared with requirements specified by environmental authorities. Control samples, 3% and 5% PET blends with RCA and CB satisfied the CBR requirements. Similarly, control samples, 3% and 5% PET blends with RCA were found to be satisfactory for RLT requirements for subbase applications.
The accumulation of polyethylene terephthalate (PET) waste from single use of drinking water bottles and fly ash (FA) generated from power stations has become the main threats to the environment every year. The cement production increases with increasing concrete demand worldwide, thereby increasing pollution caused by emission of CO and CO2 from manufacturing processes. High-strength concrete (HSC) is brittle and has low tensile strength. Moreover, HSC has low porosity and thus suffers from spalls at high temperatures. The importance of this study is to investigate the effect of PET waste on the hardened properties of HSC, reduce the HSC spalls, measures the CO and CO2 gases releases from specimens contains PET waste exposed to high temperatures and reduce the cement used in concrete. In this study, 0.25% of coarse aggregate weight was replaced by PET fiber waste and FA was used by 30%, 35%, and 40% instead of cement weight. Nanosilica (NS) material was used by 2.5%, 5%, and 7.5% of cement weight to compensate the expected strength reduction after using FA and PET. A part of the specimens was exposed to 400 °C and 700 °C to investigate the effect of high temperatures on compressive strength, flexural strength, spalling, porosity, CO and CO2 emissions, and concrete color changes. Results showed that the compressive and flexural strength were improved by the presence of FA and NS but reduced by elevated temperatures. Spalls appeared in specimens containing NS exposed to 700 °C but not in specimens containing PET combined with NS. The porosity of the control specimens increased with increasing temperature, while presence of FA and NS in HSC specimens refined the pores by 50%. The color of the specimen surface changed with increasing temperature. Hence, specimens containing PET waste and exposed to high temperatures released CO gas at concentrations higher than the allowed limitations to human breath in a closed environment.
Concrete is and has been the basic building material for most of the infrastructure for last few decades. However, the aging infrastructure is resulting in millions of tonnes of construction and demolition waste, mainly aggregates. Used plastic bottles are also a significant waste management concern of the rapidly urbanizing society. The current work is aimed at combining these two waste products and generating an alternative for conventional bricks, thus yielding a sustainable and environment-friendly building material. Used plastic bottles were filled with crushed recycled aggregate (RA) and desired water content and were sealed. Bottles containing crushed RA with size less than 425 µm had higher compressive strength as compared to those containing RA with a size between 425 µm & 4.75 mm. Also, 5% water content was found to be the most optimal in terms of compressive strength. Exposure to 3.5% saline solution for 28 days did not affect the compressive strength of such bottles significantly. Such waste material filled plastic bottles are not only cheap, zero-energy, and emission-less; they also obviate the necessity of disposal of the bottles and the waste materials. Such environment-friendly and low-cost building materials are expected to pave way for low-cost housing in economically-deprived sections of the world.
The paper presents the experimental results in terms of mechanical properties obtained for some types of innovative micro-concrete (MC) mixes. This type of concrete utilises aggregates up to 8mm and the main intended use is for non-structural elements such as insulation panels. In this respect, two concrete mixes have been prepared using fly ash (FA) as replacement for 10% of the cement dosage, and two types of waste plastic materials: polystyrene (PO) granules and recycled polyethylene terephthalate (PET) bottles aggregate. They were introduced as substitution of the fine natural aggregate (FNA) (0-4 mm), in different proportions ranging from 30% to 100%. The values of the experimentally determined mechanical strengths (compressive strength, flexural strength, split tensile strength) for both types of microconcrete are smaller than the ones of the reference mix. The complete stress-strain curves of these materials subjected to compression have been established to evaluate the absorption capacity of the strain energy. The values achieved for the micro-concrete mixes with PET aggregates were higher than the ones of the mixes embedding polystyrene granules. By increasing the dosage of waste materials as natural aggregates partial replacement, a lightweight concrete was obtained.
Vast quantities of plastic and demolition wastes are generated annually by municipal and commercial
industries in all developed and developing countries. The sustainable usage of recycled plastic and demolition
wastes as alternative construction materials has numerous environmental and economic advantages.
New opportunities to recycle plastic and demolition wastes into alternative resource materials
for construction industries would mitigate landfill issues and significantly reduce global carbon emissions.
Infrastructure projects typically consume significant quantities of virgin quarry materials, hence
the usage of plastic and demolition wastes as alternative construction materials will divert significant
quantities of these wastes from landfills. In this research, three types of recycled plastic waste granules:
Linear Low Density Polyethylene filled with Calcium Carbonate (LDCAL), High Density Polyethylene
(HDPE) and Low Density Polyethylene (LDPE) were evaluated in blends with Crushed Brick (CB) and
Reclaimed Asphalt Pavement (RAP). The blends prepared were evaluated in terms of strength, stiffness
and resilient moduli. Resilient moduli prediction models were proposed using Repeated Load Triaxial
(RLT) tests to characterize the stiffness properties of the plastic/demolition waste blends. Polyethylene
plastic granules with up to 5% content were found to be suitable as a road construction material, when
blended in supplementary amounts with demolition wastes. This research is significant, as the usage of
plastics as a construction material, in combination with demolition wastes will expedite the adoption of
recycled by-products by construction industries. Furthermore, the plastic blends were prepared without
the requirement for any further operations, such as reshaping plastic granules into fibers, hence leading
to significant energy and costs savings.
A newly developed wet packing method has been applied to measure the packing densities of blended fine aggregates (each a mixture of fine aggregates of different sizes) and mortars (each a mixture of cement and blended fine aggregate) under the wet condition, with or without superplasticizer added, and with or without compaction applied. For the blended fine aggregates, the conventional dry packing method has also been employed to measure their packing densities under the dry condition and the results show that the packing density of fine aggregate is generally higher under wet condition than under dry condition. For both the blended fine aggregates and mortars, the measured packing densities have been compared to the predicted packing densities by two existing packing models. Good agreement between the measured and predicted packing densities has been achieved with the mean absolute error being 2.1% for the blended aggregates and 1.1% for the mortars. This is the first time that the packing densities of mortar samples are directly measured and compared to predictions by packing models to verify the applicability of the wet packing method and the packing models.