预湿轻细骨料对混凝土内养护效率的影响

发布时间：2018-11-02 18:03

【摘要】：研究了2种轻细骨料的微观结构与释水性能及其预湿后对混凝土内部相对湿度和自收缩的影响.提出了混凝土内养护效率的概念,并研究了轻细骨料粒径与颗粒分布对内养护效率的影响.结果表明:轻细骨料孔隙体积和孔径皆大于硬化水泥净浆;预湿轻细骨料可以延迟混凝土由于自干燥引起的内部相对湿度降低并减小其降低幅度;内养护混凝土的自收缩和内部相对湿度存在线性关系.当轻细骨料用量占净浆体积的36%~39%时,混凝土在早期的28d内不产生自收缩.混凝土内养护效率随轻细骨料颗粒间距和半径比值的增大而减小,在轻细骨料颗粒间距和半径比值为1.1时,混凝土内养护效率为100%.
[Abstract]:The microstructure and water release properties of two kinds of lightweight aggregate and the effect of prewetting on the internal relative humidity and autogenous shrinkage of concrete were studied. The concept of internal curing efficiency of concrete is put forward, and the effects of particle size and particle distribution of lightweight aggregate on internal curing efficiency are studied. The results show that the pore volume and pore size of lightweight aggregate are both larger than that of hardened cement paste, and the prewetting of lightweight aggregate can delay the decrease of internal relative humidity and decrease the extent of reduction of concrete due to self-drying. There is a linear relationship between autogenous shrinkage and internal relative humidity of internally cured concrete. When the amount of lightweight aggregate accounts for 36 ~ 39% of the net slurry volume, the concrete does not self-shrink in the early 28 days. The curing efficiency of concrete decreases with the increase of particle spacing and radius ratio of lightweight aggregate. When the ratio of particle spacing and radius of lightweight aggregate is 1.1, the curing efficiency of concrete is 100.
【作者单位】：清华大学土木工程系;清华大学土木工程安全与耐久教育部重点实验室;
【基金】：国家自然科学基金资助项目(51108246) 交通运输部西部交通科技项目(201131823710)
【分类号】：TU528.2

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