Influence of super absorbent polymers on early-age behavior and tensile creep of internal curing high strength concrete

High strength concrete (HSC) possessing high strength and excellent durability has been widely put into use in the reinforced concrete structures. However, a low water-to-cement (w/c) ratio is usually utilized for HSC, which may increase the autogenous shrinkage due to self-desiccation, and then decrease the cracking resistance of HSC. Internal curing (IC) with super absorbent polymers (SAPs) is utilized to mitigate the autogenous shrinkage and improve the cracking resistance of HSC. Although cracking resistance and tensile creep of IC concrete utilizing SAPs under axial or circumferential restrained conditions have been investigated, research on tensile creep of IC HSC (ICHSC) utilizing SAPs under a constant initial stress to strength (s/s) ratio at early age remains insufficient. Accordingly, the early-age behavior and tensile creep of ICHSC utilizing different SAPs contents (0%, 0.57%, 0.86%, and 1.14% of the cement by weight) under a constant initial s/s ratio were experimentally investigated by the Temperature Stress Test Machine in this research. Test results and related analysis showed that: (1) the mechanical properties of ICHSC with the same basic w/c ratio decreased as SAPs content increased; (2) the autogenous shrinkage of ICHSC decreased as SAPs content increased; (3) the basic tensile creep, basic tensile creep coefficient, and specific tensile creep of ICHSC increased nonlinearly as SAPs content increased, which was due to the increase of total w/c ratio.