Restrained cracking failure behavior of concrete containing MgO compound expansive agent under adiabatic condition at early age

Abstract

The influence of MgO compound expansive agent (MCEA) on the early-age cracking failure behavior of concrete considering the influence of temperature, thermal strain, autogenous strain, and creep under the adiabatic-temperature curing mode and uniaxial restrained condition was investigated. The early-age autogenous shrinkage was effectively compensated with the addition of MCEA, and autogenous strain exhibited expansion when the dosage of MCEA was 4% and 6%. The maximum free strain, temperature drop, failure age, failure stress, and failure stress-to-axial tensile strength ratio of concrete increased with increasing dosage of MCEA when the dosage was not more than 4%. The early-age tensile creep of concrete increased with increasing dosage of MCEA. The rate of tensile stress and cracking failure potential of concrete evaluated by integrated criterion decreased with increasing dosage of MCEA when the dosage of MCEA was not more than 4%, but increased with increasing dosage of MCEA from 4% to 6%. A simplified stress-strain failure criterion based on the results of tensile strength, modulus of elasticity, and restrained cracking tests was proposed for estimating the safety of concrete under uniaxial restrained condition.