Experimental study on the properties of internal cured concrete reinforced with steel fibre

Abstract

Internal cured concrete modified with superabsorbent polymer (SAP) has received extensive attention due to its excellent crack resistance and durability, but the decrease of mechanical property caused by the macro pores left after SAP water release has limited its application to a certain extent. In this study, steel fibre was used for improving the strength and toughness of internal cured concrete modified with SAP (IC) to satisfy the development trend towards high strength concrete nowadays. Four steel fibre volume fraction dosages (0.5%, 1%, 1.5% and 2%) were adopted. Water absorption test, freeze–thaw test and dynamic compressive test were conducted to investigate the influences of steel fibre on dense degree, frost resistant, and mechanical property of IC respectively. The results showed that, 1) under standard curing conditions (20 °C and 95% RH), with the addition of SAP, the dense degree of concrete was weakened, but the frost resistant was strengthened; 2) the dense degree, frost resistant, and dynamic compressive properties of IC were considerably improved by adding steel fibre; 3) the optimal volume fraction dosage of steel fibre is 1.5%. Furthermore, a dynamic compressive constitutive model was developed, which can reflect the effects of steel fibre dosage and strain rate simultaneously.