Compressive strength, permeability, porosity, microstructure and carbon emissions of pervious concrete incorporating multi-source solid waste admixtures

Abstract

To address the insufficient mechanical strength of pervious concrete and promote the high-value utilization of industrial solid wastes, this study developed a ternary composite binder system consisting of fly ash (FA), silica fume (SF), and waste glass powder (WGP) with different particle sizes. A novel strategy involving partial replacement of FA with WGP was proposed to achieve synergistic utilization of multiple solid wastes. The effects of mixture proportions and WGP particle size on the compressive strength, permeability coefficient, and porosity of pervious concrete were systematically investigated. The modification mechanisms were further elucidated through microstructural characterization, and the carbon emission characteristics were evaluated using life cycle assessment (LCA). The results showed that the FA-SF binary system with 15% FA and 12% SF achieved a balanced performance, with a 28 d compressive strength of 43.25 MPa, permeability coefficient of 2.49 mm s−1, and porosity of 12.53%. Partial replacement of FA with WGP caused a dilution effect on early-age strength but improved long-term strength development. The maximum 56 d compressive strength was obtained at a 10% WGP replacement level, and the finest WGP particles (20–45 μm) exhibited the most pronounced enhancement effect, exceeding all binary mixtures. Microstructural analysis revealed that WGP improved pore refinement and interfacial transition zone densification through the combined effects of pozzolanic reaction and particle filling. A strong positive correlation was observed between permeability and porosity. Moreover, LCA results indicated that the FA-SF-WGP ternary system reduced CO2 emissions by 24.49% compared with the control mixture. This study establishes the relationship among mixture design, microstructure, macroscopic performance, and carbon benefits, providing experimental evidence and theoretical guidance for developing high-strength, highly permeable, and low-carbon pervious concrete.