Mechanical strengths and durability properties of pervious concretes with blended steel slag and natural aggregate

Abstract Steel slag (SS) was used to replace natural aggregate (NA) in pervious concretes (PCs) and important properties of the PCs were investigated in this work. The replacement levels of SS were 25%, 50%, 75% and 100%, respectively. The properties of the PCs, including the compressive strength, the splitting tensile strength and the flexural strength as well as the bulk density, the connected porosity and the water permeability coefficient, were studied. Additionally, the carbonation resistance and the abrasion resistance of the PCs were also evaluated. It is found that the bulk density, the connected porosity and the water permeability coefficient of the PCs increase with SS replacement level overall. Incorporating SS shows positive effects on the development of compressive strength, splitting tensile strength and flexural strength of the PCs. All the PCs show excellent carbonation resistance. Moreover, the PCs incorporating SS exhibit better abrasion resistance than the control mix. SEM images reveal that the hydrates of cement develop well in the PCs incorporating SS and rather tightly link with SS, compared with the PCs incorporating NA. The formation of a significant amount of CaCO3 is observed after carbonation. In general, steel slag can be used as alternative aggregate to replace natural aggregate in preparing PCs.