Mechanical Properties of Geopolymer Concrete with Modified Calcium and Magnesium

Geopolymer concrete has better mechanical property and environmental advantages than ordinary Portland concrete. Different amount of fly ash, Ca, Mg and the proportions of mixing ingredients are researched in this paper. Contrast by mixing different ratio of calcium to magnesium (Ca-to-Mg) into the geopolymer concrete, the mechanical property was researched. The compress experiment was fulfilled, moisture reduction was measured. The experimental results show modified geopolymer concrete with Mg/Ca can enhance the ability of water retention. The compressive strength of geopolymer concrete enhanced when ratio of Mg-to-Ca was 1:1. The peak compressive strength of geopolymer concrete reached 43.7MPa when MgO and slag occupied 133% fly ash. Slag can obviously improve the mechanical properties of the geopolymers. Modified proper ratio of Ca-to-Mg can improve mechanical performance of the geopolymer gels by 52%-1461%.