Experimental study on the drying shrinkage mitigation technique for cement-based materials in plateau: Low-heat cement and shrinkage-reducing admixture

This study performed a series of laboratory and field tests to explore the feasibility and effectiveness of low-heat Portland cement (LHC) and shrinkage-reducing admixture (SRA) in mitigating drying shrinkage of cement-based materials exposed to extreme conditions in the plateau. Additionally, microscopic tests were conducted to elucidate the underlying mechanisms. The results show that the simulated or on-site extreme conditions of the plateau could significantly accelerate water evaporation and exacerbate drying shrinkage. Also, the extreme conditions inhibited the hydration procedure and simultaneously resulted in coarser pore structures and increased pore volume in the 2.5–50 nm range. Utilizing LHC or incorporating SRA could effectively reduce the drying shrinkage under extreme conditions, with the reduction magnitudes being higher than that under normal conditions. The mechanism analysis indicated such drying shrinkage mitigation was mainly attributed to the refined pore structure for LHC and the reduction in capillary negative pressure for SRA. Field tests confirm that LHC and SRA effectively minimize drying shrinkage in concrete under extreme plateau conditions while maintaining adequate late-stage strength, thus validating their feasibility for use in such regions. • The conditions of plateau accelerated water evaporation and exacerbated drying shrinkage. • Low-heat cement and shrinkage-reducing admixture could reduce drying shrinkage. • The mechanism of employed drying shrinkage mitigation techniques was analyzed. • Field tests confirmed the effectiveness of the mitigation techniques in the plateau.