Crack resistance and durability-related properties of internally cured high-strength / high-performance concrete

Internal curing technology has been developing to counteract autogenous shrinkage of High-Strength (HSC)/High-Performance (HPC) Concrete. However, by introducing weak porous material as the internal water reservoirs, strength and durability properties can be downgraded. On the other hand, cracking due to autogenous shrinkage has extensively detrimental effect on concrete durability. Thus, when durability of HSC/HPC is considered, transport properties have to be viewed in the bundle with the risk of cracking. Research on durability of internally cured concretes in general, and durability of internally cured concretes with very low water to cement ratios in particular, attracts much interest, since very little information is available in the literature in this regard. The paper reviews the existing publications in the topic. The cracking sensitivity of concrete made at water to cement ratios of 0.21 to 0.33 and internally cured by means of water-saturated lightweight aggregate of volcanic origin (pumice) was studied in this research. In parallel, resistance to chloride penetration, air permeability and sorptivity of the same concrete mixes was tested. The experimental results demonstrate that internal curing efficiency in reducing cracking sensitivity of concrete increases with the reduction of water/cement ratio, while transport-related properties of concrete are improved, or at least as good as, those of the reference concrete.