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Problem statement: Bulldozers consume a large amount of diesel fuel and consequently produce a significant quantity of CO 2. Environmental and economic cost issues related to fuel consumption and CO 2 emission represent a substantial challenge to the mining industry. Approach: Impact of engine load conditions on fuel consumption and the subsequent...
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... It can also be observed, for example, that the increase in fuel consumption for the smallest bulldozer (D6R) is Results in Fig. 1 show that the fuel consumption 6.1 l h −1 for each 15% increase in the load factor. The −1 increases from 0.0949 l h per kW at a load factor of largest model (D11R) has an increase in fuel −1 −1 35% to 0.1348 l h per kW at a load factor of 50%. It consumption of 26 l h for each 15% increase in the also can be noted that the fuel consumption increases load factor. High values of R 2 indicate a strong positive from 0.1761 l h −1 per kW at a load factor of 65% to linear correlation between load factor and fuel 0.2178 l h −1 per kW at a load factor of 80%. High consumption for Caterpillar bulldozers. values of R 2 indicate a strong positive linear correlation According to the results shown in Fig 3, hourly between power and fuel consumption for Caterpillar cost for the largest bulldozer (D11R) ranges from $48.8 bulldozers. at load factor of 35% to $111.6 at load factor of 80%. Results in Fig. 2 indicate that fuel consumption is a The annual costs (Fig. 4) for the same bulldozer span linear function of the load factor. However, the former from $253,760 (LF = 35%) to $580,320 (LF = 80%). increases faster in absolute values for larger bulldozers. Reducing the load factor by 15%, a total of $21.2 per ...
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... To make quantification easier, the to and fro haulage distance was set at 1 km. The gasoline needed for these cars, which was derived from [84,86,87], had its ECF values taken into account. The values of the embodied carbon emissions caused by the material's acquisition and transportation are shown in Table 5. ...
Kuttanad is a region that lies in the southwest part of Kerala, India, and possesses soft soil which imposes constraints on many civil engineering applications owing to low shear strength and high compressibility. Chemical stabilizers such as cement and lime have been extensively uti-lized in the past to address compressibility issues. However, future civilizations will be ex-tremely dependent on the development of sustainable materials and practices such as the use of bio-enzymes, calcite precipitation methods, and biological materials, as a result of escalating environmental concerns due to carbon emissions of conventional stabilizers. One such alterna-tive is the utilization of biopolymers. The current study investigates the effect of Chitosan (bi-opolymer extracted from shrimp shells) in improving the consolidation and shrinkage charac-teristics of these soft soils. The dosages adopted are 0.5%, 1%, 2%, and 4%. One-dimensional fixed ring consolidation tests indicate that consolidation characteristics are improved upon the addi-tion of chitosan up to an optimum dosage of 2%. The coefficient of consolidation increases up to 7 times that of untreated soil, indicating the acceleration of the consolidation process by incor-porating chitosan. The shrinkage potential is reduced by 11% after amendment with 4% chitosan and all the treated samples exhibit zero signs of curling. Based on the findings from consolida-tion and shrinkage data, carbon emission assessments are carried out for a typical landfill liner amended with an optimum dosage of chitosan. In comparison to conventional stabilizers like cement and lime, the results indicate that chitosan minimized carbon emissions by 7.325 times and 8.754 times respectively.
... The to and fro haulage distance was considered to be 1 km for simplicity in the quantification. The ECF values for the fuel required for these vehicles were sourced from (Prusinski and Bhattacharja, 1999;Kecojevic and Komljenovic, 2011;Ashfaq et al., 2020). Table 4 lists the values of embodied carbon emissions produced by the procurement and haulage phase of the material. ...
Kuttanad region in Kerala, India, is a place that predominantly consists of soft soil formations with low shear strength and low water resistance rendering them problematic for construction purposes. Pavements constructed on such soft deposits have been subjected to structural rutting and the high erodibility of the in-situ soil necessitates the need to use suitable ground improvement techniques. The present environmental scenario demands the implementation of sustainable techniques for ground rejuvenation and effective stabilizers for enhancing engineering properties. This study investigates the amelioration of Kuttanad soft soil using chitosan as a soil amendment to improve its durability and erodibility characteristics. The untreated and chitosan-treated samples were exposed to 5 h of wetting cycle followed by 43 h of drying cycles until their failure. The unconfined compressive strength (UCS) of samples prepared with different dosages (0.5, 2, 4%) and cured for 14, 28, 60, and 90 days was evaluated at the onset and after each drying cycle to measure their durability index. Kuttanad soil was amended with 2% and cured for 90 days withstood five cycles with a UCS of more than 1,000 kPa. The drip erosion tests were used to check the erodibility performance for the aforementioned different dosages and curing periods. The 2% and 4% chitosan amended samples resisted the entire test duration of 10 min indicating the highest water erosion resistance. The findings of the current study evaluated through durability and erosion tests reinforced the effectiveness of chitosan as an effective biopolymer for soft soils subjected to constant water attack and can be easily implemented in places with such vulnerability. A typical earthen canal lining amended with chitosan reduced the carbon emissions by 8.74 and 7.44 times compared to conventional amendments like lime and cement in Carbon Footprint Analysis.
... The haulage distance was considered to be 1 km (to and fro) for ease of quantification. The ECF values were considered for the fuel required for these vehicles, which were sourced from [28,56,57]. Table 5 lists the values of embodied carbon emissions produced by the procurement and haulage of the materials phase. ...
Soil is a composite material of great interest to civil engineers. When the quality of such compo-site soils is poor, ground improvement techniques must be adopted to withstand the design load of superstructure. Existing soil stabilizers include lime and cement; however, their environmental safety and sustainable use during stabilization have been receiving increasing attention in recent years. This study investigated the use of granite sand (GS) and calcium lignosulphonate (CLS) as sustainable stabilizers that could be blended with clayey soils. The considered dosages of GS were 30%, 40%, and 50% and those of the CLS were 0.25%, 0.5%, 1%, and 1.5%. Direct shear and consolidation tests were performed on the GS-CLS-blended soil samples which were cured for 7 and 14 days. The amended stabilizers improved the shear parameters and consolidation characteristics at an optimum dosage of 30% GS and 0.5% CLS. Maximum improvements of 84% and 163% were observed in the cohesion and angles of internal friction, respectively. A significant change was also observed in the consolidation characteristics, making them practically applicable. The soil hydraulic conductivity was reduced by 14% and the coefficient of consolidation increased by 203% for 30% GS and 05% CLS. Carbon footprint analyses were performed on the soil composition that would be best suited for a typical homogenous earthen dam section. The results showed that the use of GS and CLS together reduced the carbon emissions by 6.57 and 7.7 times, compared to traditional stabilizers such as cement and lime.
... The embodied carbon factor (ECF) for this stage is based on the fuel on which the machine runs. The ECF of the fuel is sourced from Shillaber et al. [71]; Davis et al. [84]; and Kecojevic and Komljenoioc [85]. Table 5 shows the total embodied carbon emissions during the excavation of materials and the haulage distance along which the materials are transported. ...
The utilization of industrial by-products as stabilizers is gaining attention from the sustainable perspective. Referring to these lines, Granite sand (GS) and Calcium lignosulphonate (CLS) are used as alternatives to traditional stabilizers for cohesive soil (clay). The unsoaked California Bearing Ratio (CBR) test has taken as a performance indicator (as a subgrade material for low-volume roads). A series of tests were per-formed by varying dosages of GS (30%, 40%, and 50%) and CLS (0.5%, 1%, 1.5%, and 2%) at different curing periods (0, 7 and 28 days). The study revealed that the optimum dosages of granite sand (GS) are 35%, 34%, 33%, and 32% for dosages of Calcium Lignosulphonate (CLS) at 0.5%, 1.0%, 1.5%, and 2.0% respectively. The variation in reliability index is considered as greater than or equal to when the coefficient of variation (COV) of minimum specified value of CBR is 20% and the end of 28 days of curing period. The pro-posed RBDO (Reliability based design optimization) presents an optimum design methodology for designing low-volume roads when GS and CLS are blended for clay soils. The optimum mix i.e., 70% clay blended with 30% GS and 0.5% CLS (exhibiting highest CBR value) is considered as an appropriate dosage for the pavement subgrade material. Carbon Footprint Analysis (CFA) is performed on a typical pavement section considered according to Indian Roads Congress rec-ommendations. It is observed that the use of GS and CLS as stabilizers of clay save the carbon energy by 97.52% and 98.53% over the traditional stabilizers like lime and cement at 6% and 4% dosages respectively.
... where FC indicates the fuel consumption of the specific machine "m" and EF is the emission factor ( Table 3). The general function for the assessment of the fuel consumption (1 m 3 of activity) of the vibratory roller FCeq-roll [L/m 3 ] and the excavator FCeq-exc [L/m 3 ] is the following [37,41]: ...
... where P [kW], SC [kg/kWh], and Pr [h/m 3 ] are the power, the engine specific consumption, and the productivity of the equipment, respectively. The SC at full power ranges between 0.213 kg/kWh and 0.268 kg/kWh [41]; an average value of 0.25 kg/kWh is assigned to this parameter, as suggested by the existing literature [37]. ρ fuel is the mean specific weight of the fuel, which is assumed to be 0.85 kg/L [41]. ...
... The SC at full power ranges between 0.213 kg/kWh and 0.268 kg/kWh [41]; an average value of 0.25 kg/kWh is assigned to this parameter, as suggested by the existing literature [37]. ρ fuel is the mean specific weight of the fuel, which is assumed to be 0.85 kg/L [41]. LF1 and LF2 are engine load factors, depending on the equipment type. ...
The last decade has witnessed increased attention toward products, services, and works with reduced environmental impacts. In the field of road construction, the use of alternative materials, wastes, or by-products obtained from industries is attracting considerable interest. The Life Cycle Assessment (LCA) is a powerful project-level tool that allows the assessment of the environmental impacts of a road infrastructure, from raw materials production to end of life phase. In this study, the environmental impacts (in terms of global warming potential-GWP) of an embankment construction project are investigated by a cradle-to-gate approach. The analysis focuses on all the processes involved in the construction of an embankment section, from the base to the preparation of the pavement formation level. The results are provided for two different road types and two different stabilization methods, including the use of lignin and lime. All processes that contribute towards global warming are investigated and described in detail. The most important finding of the LCA, in terms of GWP, is that the production of materials is the phase that contributes the significant share of the total environmental impact (more than 90%) for all scenarios. The lowest production-related emissions can be recorded for the scenarios involving lignin treatment for the stabilization of the embankment body. Furthermore, the percentage increase in GWP ranges between 51% and 39% for transportation activities and 10–11% for construction activities, comparing the scenarios including lime stabilization with the scenarios involving lignin treatment.
... Some researchers have studied emission characteristics based on PEMS to assess vehicle emissions better [13,14]. Still, as different vehicle loads have a critical role to play on the emissions of HDDTs [15,16], it is vital to explore the operating modes and emission characteristics of these trucks under varying loads. Yao et al. [17] tested the emissions of on-road HDDTs (with a gross vehicle weight of 16.0 tons) under 0%, 50%, and 100% loads using PEMS. ...
Vehicle loads have significant impacts on the emissions of heavy-duty trucks, even in the same traffic conditions. Few studies exist covering the differences in emissions of diesel semi-trailer towing trucks (DSTTTs) with different loads, although these vehicles have a wide load range. In this context, the operating modes and emission rates of DSTTTs were analyzed under varying loads scenarios to understand the effect of vehicle loads on emission factors. First, second-by-second field speed data and emission data of DSTTTs with different loads were collected. Then, the methods for calculating the scaled tractive power (STP) and the emissions model for DSTTTs were proposed to evaluate the effect of different loading scenarios. The STP distributions, emission rate distributions, and emission factor characteristics of different loaded trucks were analyzed and compared. The results indicated that the STP distributions of DSTTTs that under the unloaded state were more narrow than those under fully loaded or overloaded conditions. The emission rates of carbon dioxide (CO2), carbon monoxide (CO) and total hydrocarbon (THC) for DSTTTs under a fully loaded state were significantly higher than those under an unloaded state. However, due to the influence of exhaust temperature, the emission rates of nitrogen oxides (NOx) among fully loaded trucks were lower than those under the unloaded state when STP bin was above 4 kW/ton. The emission factors of CO2, CO, THC, and NOx for fully loaded trucks demonstrated the largest increases at low-speed intervals (0–30 km/h), which rose by 96.2%, 47.9%, 27.8%, and 65.2%, respectively.
... Total fuel consumption by hours per equipment worked (in L)[40][41][42][43]. ...
The last decade witnessed a quantum increase in wind energy contribution to the U.S. renewable electricity mix. Although the overall environmental impact of wind energy is miniscule in comparison to fossil-fuel energy, the early stages of the wind energy life cycle have potential for a higher environmental impact. This study attempts to quantify the relative contribution of individual stages toward life cycle impacts by conducting a life cycle assessment with SimaPro® and the Impact 2002+ impact assessment method. A comparative analysis of individual stages at three locations, onshore, shallow-water, and deep-water, in Texas and the gulf coast indicates that material extraction/processing would be the dominant stage with an average impact contribution of 72% for onshore, 58% for shallow-water, and 82% for deep-water across the 15 midpoint impact categories. The payback times for CO2 and energy consumption range from 6 to 14 and 6 to 17 months, respectively, with onshore farms having shorter payback times. The greenhouse gas emissions (GHG) were in the range of 5–7 gCO2eq/kWh for the onshore location, 6–9 CO2eq/kWh for the shallow-water location, and 6–8 CO2eq/kWh for the deep-water location. A sensitivity analysis of the material extraction/processing stage to the electricity sourcing stage indicates that replacement of lignite coal with natural gas or wind would lead to marginal improvements in midpoint impact categories.
... In addition, load factor was considered the second most important factor that impacted on the energy and emission of excavators by Mario et al. (2016) who showed the variation of load factor values in different operational scenarios [43]. However, load factor effects investigated for other heavy duty diesel equipment such as bulldozers have shown that a reduction 15% of load factor may have a significant effect on reducing fuel consumption and emission CO 2 [84]. Sustainability 2017, 9,1257 16 of 26 different excavator models for the various cycle times that work in the different site conditions , showing good agreement between the actual and predicted values for ANN models. ...
... In addition, load factor was considered the second most important factor that impacted on the energy and emission of excavators by Mario et al. (2016) who showed the variation of load factor values in different operational scenarios [43]. However, load factor effects investigated for other heavy duty diesel equipment such as bulldozers have shown that a reduction 15% of load factor may have a significant effect on reducing fuel consumption and emission CO2 [84]. Multivariate linear regression (MLR) analysis was carried out twice on the same generated data for the five input parameters for each output parameter in order to predict energy consumption and CO2 emissions per hour, respectively. ...
Excavators are one of the most energy-intensive elements of earthwork operations. Predicting the energy consumption and CO2 emissions of excavators is therefore critical in order to mitigate the environmental impact of earthwork operations. However, there is a lack of method for estimating such energy consumption and CO2 emissions, especially during the early planning stages of these activities. This research proposes a model using an artificial neural network (ANN) to predict an excavator's hourly energy consumption and CO2 emissions under different site conditions. The proposed ANN model includes five input parameters: digging depth, cycle time, bucket payload, engine horsepower, and load factor. The Caterpillar handbook's data, that included operational characteristics of twenty-five models of excavators, were used to develop the training and testing sets for the ANN model. The proposed ANN models were also designed to identify which factors from all the input parameters have the greatest impact on energy and emissions, based on partitioning weight analysis. The results showed that the proposed ANN models can provide an accurate estimating tool for the early planning stage to predict the energy consumption and CO2 emissions of excavators. Analyses have revealed that, within all the input parameters, cycle time has the greatest impact on energy consumption and CO2 emissions. The findings from the research enable the control of crucial factors which significantly impact on energy consumption and CO2 emissions.
... Still, HDD trucks have a wide range of weights. Studies show that these loads have a great effect on the emissions of trucks even in the same traffic conditions (9,10). ...
Both operating modes and emissions factors for heavy-duty diesel (HDD) trucks were analyzed under different loads to understand the effect of vehicle loads on emissions. Second-by-second speed data for different loads for HDD trucks were collected first. Then a method for calculating the vehicle-specific power (VSP) values and an emissions model for heavy-duty vehicles by using the VSP value were developed to evaluate the effect of different vehicle loads. The VSP distributions and emissions characteristics for fully loaded and unloaded trucks were analyzed and compared. The results illustrate that the fully loaded vehicles spent more time driving in steady modes and the time percentage of VSP values in the bin of 0 kW/ton for fully loaded trucks was lower than the percentage for unloaded trucks. However, the time percentage at the positive VSP value was significantly higher than the percentage for the unloaded trucks. The emissions factors of fully loaded trucks were significantly higher than those of unloaded trucks. Emissions factors were affected the most at speed intervals of 20 to 40 km/h, with emissions factors for carbon dioxide, carbon monoxide (CO), oxides of nitrogen (NOx), hydrocarbon, and particulate matter (PM) at 20.4%, 23.5%, 29.0%, 11.7%, and 9.4% higher, respectively, than those levels for unloaded vehicles. With an increase of travel speed, the impact of the load on emissions weakened. Vehicle loads had the greatest effect on emissions of NOx, followed by emissions of CO. PM emissions were the least affected by vehicle loads. The impact of vehicle loads on emissions was affected by different acceleration behaviors under different loads.
Soil is a composite material of great interest to civil engineers. When the quality of such
composite soils is poor, suitable ground improvement techniques must be adopted to
withstand the design load of superstructure. Existing soil stabilization techniques include
stabilizers like lime and cement; however, their environmental safety and sustainable use
during stabilization have been receiving increasing attention in recent years. This study
investigated the use of Granite Sand (GS) and Calcium Lignosulphonate (CLS) as
sustainable stabilizers that could be blended with clayey soils. The considered dosages of GS
were 30%, 40%, and 50% and those of the CLS were 0.25%, 0.5%, 1%, and 1.5%. Direct
shear and consolidation tests were performed on the GS-CLS-blended soil samples which
were cured for 7 and 14 days. The amended stabilizers improved the shear parameters and
consolidation characteristics at an optimum dosage of 30% GS and 0.5% CLS. Maximum
improvements of 84% and 163% were observed in the cohesion and angles of internal
friction, respectively. A significant change was also observed in the consolidation
characteristics, making them practically applicable. The soil hydraulic conductivity was
reduced by 14% and the coefficient of consolidation increased by 203% for 30% GS and
05% CLS. Carbon footprint analyses were performed on the soil composition that would be
best-suited for a typical homogenous earthen dam section. The results showed that the use of
GS and CLS together reduced the carbon emissions by 6.57 and 7.7 times, compared to
traditional stabilizers such as cement and lime.
