低温环境下早期养护方式对混凝土力学性能的影响

Effect of early curing methods on mechanical properties of concrete in low temperature environment

低温环境下,早期养护方式对混凝土力学性能具有重要影响。对比分析了标准养护、自然养护、覆盖棉被养护与发热毯养护等4种养护方式下,不同胶材体系混凝土力学性能的变化。结果表明:与棉被养护、自然养护相比,发热毯养护可以显著提高低温环境下混凝土的早期抗压强度,7 d抗压强度最高可达到28 d抗压强度的97%;复掺硅灰和粉煤灰时,混凝土各龄期的抗压强均较单掺粉煤灰时高,最高抗压强度可提高至单掺粉煤灰的108.5%,对提高低温环境下混凝土的抗冻性能有利。不同养护方式导致的温度及相对湿度的改变对混凝土动弹性模量和抗压强度之间的关联性会造成影响。

Under low temperature conditions,the early curing method has an important influence on the mechanical properties of concrete. In this paper,the development of the physical properties of concrete with different cementitious composition systems un-der four curing methods which are standard curing,natural curing,quilt curing and heating curing,were compared and analyzed.The results show that compared with quilt curing and natural curing,heating curing can significantly improve the early compressive strength of concrete in low temperature environment,and the maximum compressive strength of 7 d can reach 97% of that of 28 d.At the same time,it is found that when silica fume and fly ash are mixed,the compressive strength of concrete at each age is higher than that of fly ash alone,and the maximum compressive strength can be increased to 108.5% of that of fly ash alone,which is beneficial to improve the frost resistance of concrete in low temperature environment. The relationship between dynamic elastic modulus and compressive strength of concrete is affected by the change of temperature and relative humidity caused by curing method.