Geopolymer Concrete as a Sustainable Alternative in Pavement Construction: Comparative Analysis with Conventional Concrete

The study examines the potential of utilising rice husk ash (RHA), metakaolin (MK), andcementitious solutions in the formulation of geopolymer concrete (GPC) as a replacement forconventional concrete in pavement applications. Conventional concrete made from OPC is notecofriendly due to several factors, such as high CO₂ emissions, intensive energy consumption,depletion of natural resources, etc. This study necessitated the search for an alternative ecofriendlyapproach to address these limitations. The interaction between RHA, MK, and the cementitioussolution for possible improvement in concrete pavement applications was investigated. RHA andMK were locally produced from the calcination of rice husk and kaolin at temperatures rangingfrom 600 to 800°C, while cementitious solutions were sourced in Ibadan. The constituentcementitious solutions—1M NaOH and 2M Na₂SiO₃ were solubilised in 1 litre of distilled waterand 0.12% SP430. The experimental design applied RHA:MK (30:70, 50:50, 70:30) to acementitious solution (kg/kg) at a 2:1 ratio, alongside fine and coarse aggregates. Laboratory testsconducted include compressive strength (CS), slump test (ST), and specific gravity (SG). The datawere analysed using an ANOVA at the 0.05 significance level. The control and modified concretewere evaluated at 7, 14, and 28 days. The CS for control and modified concrete reached up to 40MPa at 28 days. The 30:70 RHA:MK mix yielded the highest strength. This research indicates thatGPC derived from RHA and MK has great potential to replace OPC-based concrete in pavementapplications. Practical evaluation of geopolymer technology in greening intrastate roadinfrastructure is recommended.