Optimisation of an alkali activator solution to enhance the performance of roller-compacted concrete for pavements (RCCP)

Abstract

ABSTRACT Considering a recent surge in reducing greenhouse gases and promoting sustainable construction, geopolymer binder-based concrete materials have gained significant interest. Due to the intricacy of alkali activation and the sensitivity of roller-compacted concrete to water, alkali-activated roller-compacted concrete is rarely studied. This work optimises the performance of alkali-activated roller-compacted concrete for pavements (AA-RCCP) to address a research gap. A binder blend of 80% ground granulated blast furnace slag and 20% fly ash by the total weight of the binder was alkali-activated to produce AA-RCCP. To optimise AA-RCCP performance, 15 mix designs were developed and tested by varying five NaOH molarities ranging from 4M to 12M and three NaOH to Na2SiO3 ratios of 3R, 2R, and 1R, whereas ‘M’ signifies the molarity of NaOH, and ‘R’ denotes the NaOH to Na2SiO3 ratio. Initially, fresh properties such as optimum moisture content and maximum dry density were assessed. The effect of variation in the alkali activator solution on hardened properties, including compressive strength, flexural strength, and split tensile strength, was also evaluated. Alkali activator solution optimisation maximised mechanical performance in mix design 12M-3R. Based on the findings of this study, AA-RCCP is an effective and sustainable option for constructing pavements and other facilities.