Life cycle assessment and life cycle cost analysis of different walling materials with an environmental approach (comparison between earth-based vs. conventional construction techniques in Iran)

Abstract

Purpose: Climate change, environmental concerns, and economic problems pose challenges to the construction sector in Iran, which must provide affordable solutions while addressing environmental issues. Hence, natural earthen building materials are critically needed to reduce energy-intensive and costly construction practices dramatically. The purpose of this paper is to provide a framework for comparing life cycle assessments (LCA) and life cycle costs (LCC), for load-bearing walls of an single-family affordable housing unit in a desert part of Iran, Ardakan City. Methods: To do so, both LCA and LCC for the unit were performed, considering a cradle-to-site perspective. For this purpose, 22 load bearing wall systems are assessed, including 18 stabilized and unstabilized earthen construction techniques, such as adobe, rammed earth (RE), and compressed earth block (CEB), in addition to four conventional wall assemblies of fired brick (FB), autoclaved aerated concrete block (AAC), ceramic block (CB), and concrete masonry unit (CMU). As well as assessing the environmental impact and life cycle costs associated with the life cycle of each wall, the optimal assembly of the wall is also examined. Results: Results show that unstabilized earthen walling alternatives have significantly lower environmental impacts than conventional materials. Conclusions: Sensitivity analysis indicates that by utilizing local materials to the maximum extent possible, impacts can be further minimized. Considering the results, transportation may even account for a greater proportion of EI than wall components.