摘要
综述了目前国内外混凝土抗裂能力评价计算模型,通过综合各方面影响因素,首次建立了混凝土抗裂能力分析模型,并考虑混凝土的经时变化,创建混凝土及其结构抗裂能力评价模型,用抗裂因子Kac作为评价混凝土抗裂能力的数学参数。选择具有代表性的混凝土配合比,分别计算了粉煤灰、矿渣、硅灰、膨胀剂、减缩剂、聚丙烯纤维组分的抗裂因子,通过数学计算得出的抗裂因子的大小顺序表明:粉煤灰、矿渣能够提高混凝土的抗裂因子,而硅灰则降低了混凝土的抗裂因子。掺加纤维、减缩剂、以及减缩剂和膨胀剂复合使用能够提高混凝土的抗裂性能,特别是减缩剂和膨胀剂复合使用能够大幅度提高抗裂因子,与大小圆环、平板法等各种约束开裂试验结果具有很好的一致性。而使用膨胀剂在早期养护不充分的前提下,有降低抗裂因子的趋势。
This paper summarizes the calculation and evaluation model of anti-cracking ability of concrete at home and abroad. Through synthesizing the relevant factors, analysis model of anti-cracking ability of concrete is established for the first time, and meanwhile, considering the time-change of concrete, evaluation model of anti-cracking of concrete and its structure are es- tablished, and adopting Kao as mathematical parameter on anti-cracking performance of concrete. Choose representative con- crete mixture, proportions, such as flying ash, blast furnace stag, silica fume, expansion agent, shrinkage-reducing agent, Polypropylene fibre etc. Kac of them are calculated respectively. It is concluded that FA, slag, fibre, SRA and SRA＋EA can improve anti-cracking performance, but silica fume can decrease anti-cracking performance by comparison on K~, and among them, whiling to use shrinkage-reducing agent and expansion agent with combination can promote effectively anti-cracking performance of concrete. The calculation results of/Ca c are in according with that of restraint-cracking experiments such as big-small steel rings, flat-restraint. However, if the early curing of concrete is inadequate by using expansion agents, the trend of K~ maybe reduced.
出处
《中国港湾建设》
北大核心
2009年第1期13-17,共5页
China Harbour Engineering
关键词
混凝土
收缩开裂
约束开裂试验
抗裂能力评价模型
抗裂因子
concrete
shrinkage-cracking
restraint-crack experiment
evaluation model of anti-cracking ability
anti-cracking factor
