Page 135 - Materials Chemistry, Second Edition

6.3 Green building materials 131
FIG. 6.4 Share of global warming impacts from build-
Ceramic tiles 1% ing material use in China in 2015 (Huang et al., 2018a).
Lime Glass 0%
13%
Steel
25%
Gravel
8%
Sand
0.4%
Brick
12%

Wood
3% Cement
(nonconcrete
Concrete
use) 24%
14%

materials with lower GHG burden such as hollow concrete blocks, stabilized soil blocks, or fly
ash (Huberman and Pearlmutter, 2008).
Previous studies often analyzed the impacts of individual building materials or the mag-
nitudes of consumption, but rarely combined both. The research results of our research group
indicate that building materials with high environmental impacts per kg in China are steel,
lime, glass, wood, and cement, consistent with international studies (Thormark, 2006;
Khasreen et al., 2009b; Chau et al., 2015). Our research approach enables to identify the
contribution of specific impact and to see whether it is from a material’s per-unit associated
impact or from the magnitude of usage. Our results indicate that although steel, cement, and
concrete are key contributing materials for the estimated impacts and have similar magni-
tudes of Ev, the origin of each impact is different and thus also the potential measures to
reduce impacts. Concrete’s impact per kg (Ek) is relatively low and the magnitude of impacts
is mostly from the sheer amount used. In comparison, steel’s high impacts are due to its high
per-kg impacts rather than the masses used. Cement’s contributions to impacts are a combi-
nation of both the scale of use and the per-kg associated impacts.
Based on the findings and the fact that GHG emission burdens are currently the only en-
vironmental indicator for evaluating green building material products in the current certifi-
cation program, other key environmental indicators such as human toxicity and fossil
depletion are highly recommended to be included in the certification system. Policy strategies
such as green building materials certification programs should be given attention and
reinforced to promote the cleaner production for building materials, since currently the pro-
gram covers only concrete, glass, and ceramic tile, and is in the initial stage of implementation
in China (MIIT, n.d.). Extended producer responsibility may also be an option for the high
recycling potential materials such as concrete, steel, and wood (Guggemos and Horvath,
2003). Holding building material producers responsible for managing certain building waste
encourages manufacturers to design more environmentally friendly and recyclable materials.