Mechanical properties, permeability and freeze-thaw durability of low sand rate pervious concrete

To improve the mechanical properties, permeability and freeze-thaw resistance of pervious concrete (PC), make the gradation more reasonable, a kind of low sand rate pervious concrete (SPC) was prepared in this study. The sand was used to replace coarse aggregate with equal volume method. The effects of sand replacement rate (0%, 5%, 10% and 15%) on the compressive strength, flexural strength, effective porosity, permeability coefficient and compressive strength loss (under the freeze-thaw cycle) of SPC were studied. The results showed that the compressive strength and flexural strength increased first and then decreased with the increase of sand replacement rate, while the effective porosity and permeability coefficient showed the opposite trend. Moreover, the compressive strength of SPC with different sand replacement rate gradually decreased as the freeze-thaw cycles test continued. After 100 freeze-thaw cycles, the compressive strength loss rate of SPC with 5% sand content is the lowest and is 6.79% lower than that control group (0% content), which indicated that the addition of sand could significantly enhance the freeze-thaw durability of SPC. Based on the experimental results, the recommended sand replacement rate is 5%.