Effect of cement addition, solution resting time and curing characteristics on fly ash based geopolymer concrete performance

• Portland cement addition, fly ash content and solution resting time were studied.
• The study focused on curing temperature and curing period.
• Performance and mechanical properties of GPC were evaluated for all factors.
• Portland cement addition up to 15% improves GPC properties except workability.
• Solution resting time for 30 min yields higher performance.

Fly ash based geopolymer concrete (GPC) is an environmentally friendly concrete made from alkali activated aluminosilicate and aggregate. Generally, geopolymer concrete needs several approaches before and after casting which limits its applications. Development of geopolymer concrete became a necessity to widen its applications beyond precast concrete. This paper intends to examine the influence of fly ash content, additional Portland cement content, alkaline solution resting time, curing period and curing temperature on fly ash based geopolymer concrete. The evaluated properties of (GPC) were workability, compressive strength, splitting tensile strength, modulus of elasticity, absorption and thermal gravimetric analysis (TGA). The study results show that, generally, adding cement improves all fly ash based geopolymer properties except workability. The increase of fly ash content enhances geopolymer concrete properties. Using 30 min resting solution has a significant effect on geopolymer properties compared with using 24 h resting solution. Geopolymer concrete properties significantly affected by curing approaches which are represented in curing time and temperature.