Optimum Mix for Pervious Geopolymer Concrete (GEOCRETE) Based on Water Permeability and Compressive Strength

Abstract

The production of ordinary Portland cement (OPC) consumes considerable natural resources and energy, and it also affects the emission of a significant quantity of CO 2 in the atmosphere. This pervious geopolymer concrete study aims to explore an alternative binder without OPC. Pervious geopolymer concretes were prepared from fly ash (FA), sodium silicate (NaSiO 3 ), sodium hydroxide (NaOH) solution, and coarse aggregate (CA). The effects of pervious geopolymer concrete parameters that affect water permeability and compressive strength are evaluated. The FA to CA ratios of 1:6, 1:7,1:8, and 1:9 by weight, CA sizes of 5–10, 10–14, and 14–20 mm, constant NaSiO 3 /NaOH ratio of 2.5, alkaline liquid to fly ash (AL/FA) ratios of 0.4, 0.5, and 0.6, and NaOH concentrations of 8, 10, and 12 M were the pervious geopolymer concrete mix proportions. The curing temperature of 80 °C for 24 h was used. The results showed that a pervious geopolymer concrete with CA of 10 mm achieved water permeability of 2.3 cm/s and compressive strength of 20 MPa with AL/FA ratio of 0.5, NaOH concentration of 10 M, and FA:CA of 1:7. GEOCRETE is indicated to have better engineering properties than does pervious concrete that is made of ordinary Portland cement.