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1. Introduction
1.1 What are “alternative” building and construction materials?
The building and construction sector has an enormous environmental impact. Buildings make up roughly 75 percent of total US electricity consumption and contribute over 30 percent of US greenhouse gas emissions (Harris, 1999; Khasreen et al., 2009). Materials are a large portion of the built environments’ impact (Horvath, 2004). Specifying more sustainable materials for construction has been happening for a long time (Anink et al., 1996); however, as more options come on to the market, it has become increasingly difficult for designers and engineers to understand what is available and how best to specify them for projects.
There are a variety of strategies for achieving environmental impact reduction in the building and construction sector. Green building guides mention a wide diversity of “alternative” materials that can replace conventional product in this sector. From a review of these building guides that will be further detailed in the methods and results section, the authors developed four broad categories to sort these alternatives into as shown in Table I: first, environmentally benign materials; second, materials that are or can contain recycled, reused or remanufactured materials; third, bio-based materials; and fourth, materials that employ strategies through-out their supply chain for achieving impact reductions.
The environmentally benign material category acts as a catch-all for broad strategies of reducing environmental impacts. Non-toxic materials have low or zero negative impacts to human health; they have potential to improve indoor air quality, occupant health, and manufacturing conditions when replacing conventional counterparts. For example, latex and other water based paints have been developed to replace traditional high volatile organic compound (VOC) paints providing significant indoor air quality improvements. Zero waste materials are designed to systematically decrease magnitude of materials ending up in disposal pathways and ultimately landfills (Song et al., 2015). Low impact materials have the potential to reduce energy intensity and carbon emissions over their lifecycle when replacing conventional materials. The weight, volume or mass of building products can be reduced when materials with low density but high structural performance are used; such light-weighting can provide impact savings mainly due to reduced transportation emissions. For example lightweight concrete has a reduced dead load and requires less reinforcing providing impact savings...