Influence of maximum paste coating thickness without void clogging on the pore characteristics and seepage flow of pervious concrete.

• A new method was proposed for determining the maximum paste coating thickness. • Digital models of pervious concrete were created. • Influence of maximum paste coating thicknesses on the pore characteristics and seepage flow was investigated. • An empirical formula was proposed to determine the Kozeny–Carman constant. The determination of the maximum paste coating thickness on aggregate (MPCT) without void clogging is essential for effectively controlling the permeability of a pervious concrete (PC). The main objective of this study is to investigate the influence of varying MPCTs on the pore characteristics and seepage flow of PC. A new method was proposed for determining the MPCT of PC, and the relationships between the MPCT and the rheological properties of cement paste were established. Subsequently, digital models of PC with varying MPCTs were created, and the connected pore was extracted for analysis of pore characteristics. Seepage flow simulations were conducted to analyze the permeability characteristics of PCs under varying MPCTs. The results indicate that the pore characteristics are directly influenced by the MPCT, in which the effective porosity, specific surface, and tortuosity show linear correlations with the MPCT. When the MPCT ranges from 0.44 to 0.99 mm, the pore size of the PCs exhibits a single-peak distribution ranging from 1.4 to 13.5 mm, while the coordination number of the pores is distributed within the range of 1 to 14. Additionally, the permeability coefficient of PC decreases as the MPCT increases. When the MPCT exceeds 0.85 mm, the permeability coefficient drops to less than 1 mm/s, and the rate of decrease slows down. An empirical formula was proposed to determine the Kozeny–Carman (KC) constant, which improves the accuracy of the KC equation in predicting the permeability of PC. The findings presented in this study serve as a reference for the design of mixture proportions and the optimization of permeability in PC. [ABSTRACT FROM AUTHOR]