Effect of hybrid curing on cracking potential of high-performance concrete

• Cracking potential of HPC with internal curing and SRA was studied.
• Internal curing did not significantly reduce the cracking potential.
• Shrinkage reducing admixture reduced the cracking potential to only a small extent.
• Application of hybrid curing resulted in significant reduction cracking potential.
• Results indicate the synergy between internal curing and SRA.

Internal curing technology has been developed to counteract autogenous shrinkage of high-performance concrete. However, the total shrinkage of internally cured concrete is reported to be almost unchanged after exposure to drying. On the other hand, shrinkage reducing admixtures have been successfully used to reduce drying shrinkage. A hybrid curing technique that combines internal curing with shrinkage reducing admixture seems to be a promising approach for reduction of total shrinkage and cracking potential of high-performance concrete. Ring test of concrete made at water to cement ratio of 0.33 and internally cured by water-saturated lightweight aggregate and super-absorbent polymer and their combination with shrinkage reducing agent was studied. In parallel, compressive and splitting strength, drying shrinkage and mass loss of the same concrete mixes were measured. The results demonstrate the synergy between internal curing and shrinkage reducing admixture resulting in a marked reduction of cracking potential.