混凝土内养护技术国内外研究进展

Research progress on internal curing concrete

低水胶比混凝土因其内部自干燥,早期产生相当大的自收缩变形,一旦混凝土的变形受到约束,就会在混凝土内部产生内应力,进而导致混凝土早期开裂。饱水多孔材料掺入混凝土,提高了混凝土内部的湿度,胶凝材料的水化程度得到加大,从而抵抗混凝土水化过程中的自干燥,降低混凝土的自收缩。阐述了国内外混凝土内养护技术的现状,分析了内养护技术的机理以及内养护对混凝土性能的影响。

The concrete with low water/brinder（W/B ） ratio experiences self-desiccation during its hydration process, leading to a consid- erable high autogenous shrinkage deformation during hardening.In case the free deformation of the concrete is prevented, internal stresses are introduced, which can lead to the early shrinkage-cracking.By adding pre-saturated lightweight aggregates （LWA） and super absorbing polymers（SAP） into the concrete with low W/B-ratio as internal curing agents and by adding additional curing water to the concrete mixture, the internal relative humidity decline of the concrete delays at an early age ,the hydration degree of cement can be promoted,the self-desic- cation during hydration of the concrete is counteracted and thus the autogenous shrinkage of the concrete with low W/B-ratio can be signif- icantly reduced.The current research situations of internal curing technologies are discussed, the action mechanism and effects of internal curing on concrete are analyzed.