Bond stress-slip of fly ash-based geopolymer concrete: a review

Abstract

The bond behavior of geopolymer concrete using Class F fly ash under pull-out loading is still under investigation. Fly ash, as a by-product material, is revised in terms of material (chemical composition, concentration of alkaline activator and curing scheme) and mechanical (compressive strength, concrete cover-to-diameter ratio and embedment length ld) to replace Ordinary Portland cement (OPC) as construction materials. This paper will review bond mechanism of geopolymer concrete (GPC) contributed by both material and mechanical properties. Generally, higher bond strength could be observed in specimens with higher compressive strength. Also, c/db ratio shows the same observation, with strength gain from increment of c/db ratio. An increase of ld, however, result in reduction of bond strength. The trend for bond stress-slip curves of GPC is similar to OPC based on previous equation proposed by several authors, proving that its utilization is suitable for structural application. Those observations will be reviewed further in this paper as a preliminary study to investigate the effect of those parameters experimentally on GPC pull-out specimens for development towards utilization of this green cement in construction industries.