Geopolymer pervious concrete pavement system with limestone aggregates

Abstract

Permeable concrete is the type of concrete that allows the drainage of stormwater. When combined with geopolymer, favorable properties were established. This study is set to analyze geopolymer pervious concrete under the application of pavement systems. The aim of this research is to build a green and sustainable system using limestone aggregates with geopolymer concrete. Three different Geopolymer Pervious Concrete (GPC) mixes were conducted with medium aggregates and an aggregate to metakaolin ratio varying between 4, 6, and 8. The mixes were cast in different types of specimens using a previously studied casting method. The mixes were later compared to three mixtures of Ordinary Portland Cement Pervious Concrete (CPC) having the same porosity. The mixes were tested for various properties such as compressive strength, tensile strength, flexural strength, porosity, infiltration rate, elastic modulus, etc. After obtaining the mechanical properties experimentally, the pavement design was performed through calculating the maximum Equivalent Single Axle Load (ESAL) that it could resist. As an outcome, cylinders (20 x 10 cm) turned out to be a weak representative for pervious concrete. GPC and CPC yielded similar results in compression that ranged between 4.7 MPa and 16.5 MPa. CPC gave a higher flexural strength as the porosity was decreasing reaching 2.68 MPa for 12% porosity while GPC resulted in 1.91 MPa for the same porosity. The infiltration rate of CPC was more acceptable than that of GPC in all three mixes. On the other hand, the tensile test was rejected for both samples as failure was occurring at the weak point and splitting into more than two parts due to the weak bonds between the layers caused by the casting method. In terms of parking lot pavement design, the GPC resulted in acceptable bearing ESAL for three different thicknesses 6 in, 10 in, and 14 in. Hence, it could be concluded that the GPC is acceptable to be used for parking lot pavements since it can resist the load. However, a lot of studies must be carried out to develop this material in terms of curing time and early-stage strength, etc.