This study investigates the use of corncob ash (CCA) as a partial replacement for cement in pervious concrete, with a focus on its potential to enhance sustainability while maintaining performance. This research was necessitated by the urgent need to mitigate the high carbon footprint of the construction industry by transforming underutilized agricultural residues into value-added cementitious materials for sustainable urban drainage systems. Pervious concrete is crucial for managing stormwater and reducing surface runoff; however, the environmental impact of cement production remains a significant challenge due to its high CO₂ emissions. Corncob ash, an agricultural waste product, presents an opportunity to mitigate the environmental impact of concrete by offering a pozzolanic material that can replace a portion of cement, thus reducing both material costs and CO₂ emissions. While CCA has been studied in conventional concrete, there is limited research on its application in pervious concrete, particularly in terms of long-term performance, permeability, and environmental impact. The primary aim of this study is to evaluate the effects of CCA as a partial cement replacement in pervious concrete, specifically addressing compressive strength, porosity, permeability, and the environmental impact in terms of embodied energy and CO₂ emissions. Experimental testing was conducted on pervious concrete mixes with 10%, 20%, 30%, and 40% CCA replacement, comparing them to control mixes. The results indicate that CCA enhances the permeability and environmental performance of pervious concrete but leads to a reduction in compressive strength at higher replacement levels. The key finding is that CCA20 (20% replacement) provides the best balance between cost-effectiveness, environmental benefits, and performance, making it a promising alternative for sustainable pervious concrete. This research contributes valuable insights into optimizing CCA usage and its potential for large-scale implementation in the construction industry.
Wickramasinghe et al. (Tue,) studied this question.