Investigating the Influence of Recycled Coarse Aggregate and Steel Fiber on the Rheological and Mechanical Properties of Self-Compacting Geopolymer Concrete.

This experimental study presents the effect of steel fiber (SF) and recycled coarse aggregate (RCA) on the fresh and hardened properties of Self-compacting geopolymer concrete (SCGC). Sixteenth alkali-activated based metakaolin (MK) concrete mixtures with constant binder content of 500 kg/m³ incorporated 0, 0.5, 1.0, and 1.5% volume fraction of SF and 0, 10, 20, and 30% RCA as a partially replacement for natural coarse aggregate (NCA) with sodium hydroxide concentration of 12 Molarity at ambient conditions. Fresh state of SCGC were examined slump flow, T500 flow, V-funnel, and L-box test. At 28 and 90 days the compressive strength and splitting tensile strength were investigated, the flexural strength was evaluated at 90 days. The results highlighted that RCA (30%) and SF (1.5%) significantly constrain the fresh properties of SCGC mixes. Moreover, SCGC incorporated RCA can be produced with compressive strength as high as 31.91-41.13 at 28 and 90 days, respectively. However, 1% SF and 30% RCA in MK-based SCGC appear better performance than the control mixture and leads to an ecologically friendly concrete mix that has appropriate hardening properties and that would contribute to the longevity of the construction industry. [ABSTRACT FROM AUTHOR]