Evaluation of internal curing impact on the mechanical properties and durability of high-performance concretes

The durability and service life of concrete structures reduce considerably due to the induced cracks from the concrete volumetric changes. Therefore, adopting appropriate measures to overcome this drawback is crucial. In this respect, this research was conducted to investigate the effects of internal curing on high-performance concrete's autogenous shrinkage and mechanical properties. For this purpose, the curing capability of concrete specimens containing a pre-saturated artificial aggregate (LECA), superabsorbent polymers (SAP), and recycled crushed bricks (RCB) as internal curing agents was investigated. The volumetric changes and mechanical properties tests of internal cured concrete specimens, including autogenous shrinkage, the compressive, tensile, bending strength, modulus of elasticity, and X-Ray diffractometer (XRD) tests, were performed to investigate the effect of internal curing on the micro-structures and hydration procedure. According to obtained results, the SAPs could omit the autogenous shrinkage of studied concrete specimens. The test results of specimens containing LECA also showed a reduction in the autogenous shrinkage value; however, using LECA caused a reduction in the mechanical properties. In comparison, recycled crushed bricks could reduce the concrete autogenous shrinkage and improve its mechanical properties.