Environmental assessment of construction waste prevention: A case study in a social housing project in Southeast Brazil

This study analyzed construction waste prevention measures applied to a social housing project, with life cycle assessment (LCA), by three scenarios: base case scenario (BCS) – a single family house built with masonry blocks; prevention scenario 1 (PS1) – BCS assuming a theoretical optimization in materials consumption; prevention scenario 2 (PS2) – a house built with cast-in-situ concrete walls. The prevention scenarios showed waste reductions of 4% (PS1) and 36% (PS2). The environmental impacts have been evaluated by using CML baseline v.3.05; the impact categories were selected according to the EN 15.978:2011: global warming potential (GWP), acidification (AP), eutrophication (EP), ozone layer depletion (ODP), photochemical ozone formation (POF), abiotic depletion (AD), and abiotic depletion – fossil fuels (ADF). The PS1 reduced environmental impacts by 5% whereas PS2 increased by 15%, compared with BCS. The most critical construction steps for BCS and PS1 were coating and superstructure, whereas for PS2 were superstructure and painting. The materials extraction and production stage represent about 90% of the total impacts. The most critical materials for BCS and PS1 were concrete, cement, and steel, whereas for PS2 those were concrete, steel, and paint. The most relevant categories for the three scenarios analyzed were GWP, ADF, and AP. The waste management stage was irrelevant in generating impacts, contributing for less than 1% of the total impacts. These results highlight that despite reducing waste generation, prevention does not necessarily reduce the overall impacts of the edification, and therefore, the materials and construction methods used are especially relevant.