矿物掺合料改善水泥砂浆脆性和抗裂性的研究

发布时间：2018-01-07 09:24

本文关键词：矿物掺合料改善水泥砂浆脆性和抗裂性的研究　出处：《人民黄河》2016年09期 　论文类型：期刊论文

【摘要】：随着高强混凝土在工程中的不断应用,混凝土的水灰比越来越小,减小水灰比虽然可以提高混凝土或砂浆的抗压强度,但同时也会使其脆性增强、抗裂性变差。矿物掺合材料在工程中使用很广泛,它们的掺入对混凝土的脆性、强度都会产生影响。选取三种工程中较常采用的矿物掺合材料——粉煤灰、硅灰和MgO粉末,通过改变掺量和掺加方式来研究它们对砂浆强度、脆性的影响。试验结果表明,砂浆脆性随着自身强度的提高和养护龄期的延长而不断增强。随着胶凝材料含量的增大,砂浆的抗压强度提高,同时其脆性有一定程度下降。粉煤灰掺量越高,砂浆脆性下降得越多,但粉煤灰的掺入对砂浆早期强度的发展会产生不利影响。掺入一定量的硅灰不仅能提高砂浆的抗压强度,而且能很好地降低其脆性,提高抗裂性。掺入MgO粉末也能降低砂浆的脆性,但同时对其抗压强度特别是早期抗压强度有明显降低作用。因此,在实际工程中,建议双掺适量粉煤灰和硅灰,这不仅可以显著降低砂浆的脆性,而且可以弥补粉煤灰对早期强度的不利影响,使中后期强度不低于甚至高于基准砂浆的强度。
[Abstract]:With the continuous application of high strength concrete in engineering, concrete water cement ratio is more and more small, reducing the water cement ratio can improve the compressive strength of concrete or mortar, but also will make it more brittle and crack resistance variation. Mineral admixtures is widely used in engineering, the incorporation of concrete the brittle strength, will have an impact. More often adopted three kinds of engineering of mineral admixtures, fly ash, silica fume and MgO powder by changing the dosage and adding ways to study their influence on mortar strength, brittleness. The experimental results show that the brittleness increases with increase of mortar strength and the curing period. With the increase of the content of cementitious materials, improve the compressive strength of mortar, and its brittleness decreased to a certain extent. The amount of fly ash is higher, the more brittle mortar decreased, but the incorporation of fly ash The development of the early strength of mortar will be adversely affected. Adding certain amount of silica fume can improve the compressive strength of mortar, but also reduce its brittleness, improve crack resistance. The incorporation of MgO powder can reduce the brittleness of mortar, but also on the compressive strength especially early compressive strength significantly decreased therefore, in practical engineering, proposed double mixing proper amount of fly ash and silica fume, which not only can reduce the brittleness of mortar, and can compensate for the bad influence on the early strength of fly ash, the late strength of not less than even higher than reference mortar strength.

【作者单位】：河南城建学院交通运输工程学院;西安建筑科技大学土木工程学院;
【基金】：国家自然科学基金资助项目(51078306)
【分类号】：TQ177.62
【正文快照】： 通常情况下,随着混凝土或水泥砂浆强度等级的提高,其脆性会增强,抗裂性会变得越来越差。混凝土或砂浆一旦开裂,就会对其适用性和耐久性产生一定程度的影响,严重的还会影响到结构的安全。因此,研究混凝土或砂浆脆性的发生发展机理,弄清楚影响其脆性的主要因素,通过试验和理论分

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