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The design of building foundations has usually been based on tradition, local practice, experience, and structural design codes. Safety is invariably considered the main factor and environmental criteria (or, in general, sustainability) is seldom given due consideration. However, similar safety indicators can be achieved with different variables and a minimum safety factor must always be ensured. The main objective of this study is, from an environmental perspective, to assess the influence of the construction system (cast-in-situ or precast), foundation type (rigid or flexible), and structural code (EC-2 or EHE-08) in the case of a concrete shallow foundation (CSF), using Life Cycle Assessment (LCA). Applying this methodology, the materials (concrete and steel) yielded the highest impacts in all categories, at around 95% for cast-in-situ CSFs and at around 85% for precast CSFs, both in relation to global warming. Consequently, optimization of the amount of these materials is crucial when considering the particular variables selected in this study. The results showed that cast-in-situ and flexible CSFs at moderately shallow depths (and therefore with less steel reinforcement) and precast CSFs with considerable reductions in concrete volumes (due to sloped shapes) had lower environmental impacts. In addition, cast-in-situ CSFs constructed in accordance with the EHE-08 structural code showed lower impacts, while precast CSFs complying with the EC-2 code were environmentally preferable. However, a specific study might be required for specific factors in each case (loads, soil type, structural settlement, among others). Relevant environmental effects associated with the three variables should therefore be given specific consideration in the development of structural design codes and future constructions. [ABSTRACT FROM AUTHOR]

Green and grey stormwater management infrastructures, such as the filter, swale and infiltration trench (FST), can be used to prevent flooding events. The aim of this paper was to determine the environmental and economic impacts of a pilot FST that was built in São Carlos (Brazil) using Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). As a result, the components with the greatest contributions to the total impacts of the FST were the infiltration trench and the grass cover. The system has a carbon footprint of 0.13 kg CO 2 eq./m 3 of infiltrated stormwater and an eco-efficiency ratio of 0.35 kg CO 2 eq./USD. Moreover, the FST prevented up to 95% of the runoff in the area. Compared to a grey infrastructure, this system is a good solution with respect to PVC stormwater pipes, which require a long pipe length (1070 m) and have a shorter lifespan. In contrast, concrete pipes are a better solution, and their impacts are similar to those of the FST. Finally, a sensitivity analysis was conducted to assess the changes in the impacts with the varying lifespan of the system components. Thus, the proper management of the FST can reduce the economic and environmental impacts of the system by increasing its durability. [ABSTRACT FROM AUTHOR]

Abstract: A life cycle assessment to evaluate the environmental impact of urban sewage sludge use as alternative fuel or raw material in clinker production was carried out. In order to quantify in detail the overall environmental impact of both scenarios, the sewage sludge treatment process and the transport to cement facilities for both alternatives were considered. The substitution ratio of fuel (petcoke) and raw material (limestone) was fixed between 5 and 15% according to the cement production plant limitations. Both scenarios show CO2 savings when compared to the clinker production without substitution. The mid-point and end-point analysis were favourable to the fuel substitution with savings ranging from 3 to 7% compared to the raw material substitution and also to base case without substitution. The influence of the amount of sewage sludge used for both scenarios indicates that fuel substitution reduced the CO2 emissions when the amount of substitution is increased, while other mid-point and end-point categories were proportionally favourable to the fuel substitution scenario. Additionally, the influence of the substituted material characteristics showed that low heating value (fuel substitution) and CaO addition in lime stabilized sludge (raw material substitution) are critical parameters in terms of environmental impact in clinker production. The fuel substitution represents a significant environmental improvement compared to the raw material substitution scenario and clinker production without substitution. [Copyright &y& Elsevier]