蒸养超细粉煤灰高性能混凝土性能试验研究

Experimental studies on capabilities of steam curing ultra-fine fly ash high performance concrete

研究蒸养条件下超细粉煤灰高性能混凝土的强度、弹性模量和应力-应变行为以及体积稳定性和耐久性能,结合微观测试手段,探讨超细粉煤灰在蒸养条件下的作用效应及其机制.试验结果表明,超细粉煤灰能显著提高混凝土的蒸养适应性,蒸养超细粉煤灰高性能混凝土的后期强度、弹性模量具有较好的增长率.与普通蒸养混凝土相比,蒸养超细粉煤灰高性能混凝土的脆性降低,塑性变形能力明显增强,干燥收缩明显降低,且抗氯离子渗透性能显著提高.超细粉煤灰可改善蒸养条件下混凝土的内部水化产物组成及其孔结构,降低混凝土的孔隙率,提高混凝土耐久性.

This experimental study addresses the mechanical properties, including strength, elastic modulus and strain-stress curve in steam curing, volume stability, and durability, of uhra-fine fly ash high performcmce concrete （UFA-HPC）. The effect and mechanism of ultra-fine fly ash in steam curing are also discussed. The results indicate that uhra-fine fly ash can improve the adaptability of concrete in steam curing condition. The compressive strength and elastic modulus of the UFA-HPC are in growth tendency in comparion with ordinary Portland concrete （OPC）. The brittleness and dry shrinkage of the UFA-HPC are decreased, but the capability of plastic deformation is strengthened in steam curing, and the capability of the UFA-HPC resisting chloride ion attack is enhanced. Ultra-fine fly ash can improve inner composition of hydration product and porosity of concrete, and increase concrete durability in stream curing.