One-Year study of restrained shrinkage and creep behaviours of geopolymer concrete

Abstract

The viability of geopolymer concrete (GPC) for industrial applications has been increasing in recent years by utilising solid alkali activators and curing at ambient temperature. With higher viability and desirability for engineering applications, their dimensional stability and serviceability properties remained a focal point for investigation. The one-year dimensional stability of GPC was studied using standard shrinkage and creep tests. Furthermore, a novel photogrammetry technique was introduced and utilised to measure the shrinkage of concrete slabs in restrained conditions. The 56-day drying shrinkage of GPC specimens was between 280 and 600 microstrain, which is suitable for most structural engineering applications. GPC experienced a slightly higher drying shrinkage in free condition than conventional concrete when the fly ash/slag mix ratio was 60/40. However, GPC displayed 38–57% lower shrinkage in restrained conditions than the conventional counterpart. GPC specimens also experienced lower creep strain and coefficient when compared to normal concrete. The GPC shrinkage and creep performance revealed that slag content played a crucial role, as the free shrinkage and creep strains in slag-dominant GPC were the highest.