Effect of curing methods on autogenous shrinkage and self-induced stress of high-performance concrete

Early-age cracking induced by autogenous shrinkage is still the major problem relating to the use of high-performance concrete (HPC) in reinforced concrete structures. Recent studies have proven that the presaturated recycled porous ceramic coarse aggregate (PCCA) could be successfully used to mitigate autogenous shrinkage of HPC. This study examines the behavior of low-autogenous shrinkage silica fume HPC developed using three different curing techniques. A binary system, made with a combination of shrinkage-reducing agent (SRA) and expansive additive (EX); a hybrid system, containing internal curing provided by the PCCA and SRA combined with EX; and a mono-incorporation of the PCCA were selected for this investigation. The effect of each curing technique on the compressive and splitting tensile strengths, elastic modulus, autogenous shrinkage, and internal self-stress were investigated. The results obtained indicated that HPC produced using 20 to 30% of the PCCA by volume as a partial replacement of the total coarse aggregate content could significantly reduce the magnitude of autogenous shrinkage and the induced self-stress of HPC, whereas 30% of the PCCA seemed to be the optimum content and performed much better than the treated concrete with anti-shrinkage agents. In addition to its efficient shrinkage reducing effect, the incorporation of the PCCA showed a better compressive strength development than the references' mixtures. Moreover, the hybrid curing technique containing (SRA + EX) and 20% of the PCCA provided a better enhancement for shrinkage compensating concrete than either the mono-incorporation or the binary curing system.