Performance and Implementation of Low-Quality Recycled Concrete Aggregate

Our project seeks to greatly reduce the energy required for concrete production by using mostly recycled concrete. The use of recycled concrete aggregate (RCA) is not a new phenomenon, but has not been studied in the context of low-cost disaster reconstruction efforts, which was our focus—specifically, the 2010 earthquake in Haiti. In our experiments, we sought to replicate the variability in concrete quality that is often found on poorly supervised construction sites. Construction companies in developing nations often add water to cement, which decreases the concrete’s final structural strength. Thus, our experiment produced several samples of concrete with a high water to concrete ratios, which we then crushed and turned into RCA to produce new concrete. We tested both our initial concrete samples and the final concrete products for compression and tensile strengths. From our data, we were able to conclude that RCA is a reasonable low-cost aggregate in the production of concrete structures. Our experimental results suggest that some of the downsides of low quality RCA can be offset by high water absorption in the process of making new concrete. Finally, we discuss possible implementations of our findings and suggest avenues of future research. Consilience Chang et al.: Performance of Low-Quality Concrete as RCA Author’s Note Special thanks to Prof. Christian Meyer for sponsoring and advising this project as part of his broader Ultra-Low-Cost Housing for Haiti initiative. We are also greatly indebted to Adrian Brugger, manager of Carleton Lab, as well as the lab technicians of Carleton Lab, for maintaining testing equipment and supporting our experiments. This project also benefited greatly from the help of Minh-Thu Ho and James Jelinek, who helped with day-to-day lab procedures and specimen testing.