Tensile creep and cracking potential of high performance concrete internally cured with super absorbent polymers at early age

Abstract

High performance concrete (HPC) has been extensively applied in practice. However, the water-to-cement (w/c) ratio of this concrete is low, high temperature rise and high self-desiccation will occur, and both of which can increase the cracking potential of HPC at early age and then decrease the service life of concrete structures. Therefore, super absorbent polymers (SAPs) are applied in HPC as an internal curing (IC) agent. Although the autogenous shrinkage, relative humidity, and stress relaxation of concrete internally cured with SAPs have been studied, investigations on the influence of SAPs on the tensile creep and cracking potential of HPC are still lacking. In present study, the influence of SAPs as an IC agent on the temperature, autogenous shrinkage, restrained stress, basic tensile creep, and cracking potential of HPC were simultaneously studied by Temperature Stress Test Machine. Test results and corresponding analysis showed that: (1) the adiabatic temperature rise of HPC was 27.6, 29.3, 31.0, and 34.9 °C and increased with the increase of amount of SAPs; (2) the rate of restrained tensile stress of HPC was 1.7, 1.5, 1.4, and 1.2 MPa/day and decreased with the increase of amount of SAPs; (3) the specific basic tensile creep of HPC at the age when the restrained specimen of mixture SAP-0 cracked was 45, 23, 13, and 7 με/MPa and decreased with the increase of amount of SAPs; (4) a model for predicting the basic tensile creep compliance function of HPC considering the influence of amount of SAPs was proposed; (5) the cracking potential of HPC which was based on the integrated criterion decreased with the increase of amount of SAPs.