Functional characteristics of sustainable pervious cement concrete pavement modified by silica fume and travertine waste

Innovative solutions are essential to address the environmental and economic challenges posed by travertine mining waste. By assessing various silica fume (SF) levels, an optimal incorporation rate of 10% SF was first identified. The research further explores replacing natural limestone aggregate with WTA, either completely or partially, in pervious concrete (WTAPC), analyzing its mechanical, hydraulic, and water-purification properties. Notably, WTAPC with 100% WTA substitution achieved a significant increase in permeability, from 1.22 to 4.53 mm/s, while maintaining adequate mechanical strength. The heavy metal ion removal capabilities by WTAPC were affected by the contact time between the solution and the specimen, with Pb2+ showing the highest adsorption priority. Moreover, the flowability of pervious concrete in higher volumes might not be precisely predicted by the pre-test results derived from small-volume samples. Additionally, higher superplasticizer dosages were found to enhance cement paste flowability, reducing porosity.