Multi-aspect engineering properties and sustainability impacts of geopolymer pervious concrete

This study aimed to comprehensively evaluate multi-aspect engineering properties and sustainability impacts of geopolymer pervious concrete. Geopolymer binder was prepared using metakaolin (MK) or fly ash (FA) with granulated blast furnace steel slag (GBFS) and used to fabricate pervious concrete; while conventional pervious concrete was made with Portland cement (PC). The strength and durability results show that the MK based pervious concrete exhibited superior performance in mechanical property (3200 psi compressive and 520 psi splitting tensile strength) and lowest mass loss (3%) after 70 cycles of freeze & thaw test. The FA based pervious concrete had about 10% higher splitting tensile strength and better raveling resistance than the PC based pervious concrete, but its freeze & thaw resistance was the lowest (8% mass loss after freeze & thaw test). The hydraulic conductivity test results show that the porosity was the major influence factor for permeability coefficient. The permeability coefficients increased from 3.5 to 12 mm/s with the increase of porosity from 13.5% to 24.5%. However, the binder type had no obvious effect on the permeability and clogging resistance. In addition, life-cycle assessment (LCA) was applied to quantify energy consumption and greenhouse gas (GHG) emission of pervious concrete with different raw materials. The FA based pervious concrete showed the lowest energy consumption, while the MK based pervious concrete had slightly greater energy consumption than conventional pervious concrete. Compared with PC based one, the GHG emissions of MK and FA based pervious concrete could be reduced by 33% and 53%, respectively.