全球变化知识资源中心

The environmental impacts of natural aggregates (NA) and recycled concrete aggregates (RCA) production for use in road pavements have been evaluated in this study through an attributional life cycle assessment (LCA) from cradle to gate. Such effort is relevant considering the increasing interest of national agencies in applying recycled aggregates for construction and rehabilitation (C&R) of highway infrastructures. The study used site-specific data from two different aggregate production plants, stationary and mobile, both located in the northern region of Colombia. The stationary facility produces NA, and the mobile plant processes a combination of NA and RCA from the demolition of Portland cement concrete (PCC) pavements in the city of Barranquilla. The aggregates produced in the stationary facility are generally used as road base and subbase materials, and in the production of PCC, whereas the recycled mobile plant produces aggregate for subbase and road base mainly. Two scenarios were contemplated in the study. The first scenario involved extraction, hauling, and processing of NA. The second scenario involved aggregate (limestone) extraction, hauling, and recycling of RCA, and finally processing the combination of NA with RCA. The environmental impacts related to the production process of both stationary and mobile plants were evaluated using the computer program SimaPro 8.4.0 and the impact assessment method IMPACT 2002(+). The results showed that diesel fuel is the principal energy used in both production processes, and is mainly responsible for the negative impact on respiratory inorganics, global warming, and nonrenewable energy. Results were very sensitive to transportation distances.