玄武岩纤维对低温下钢渣粉混凝土力学性能影响的试验分析

发布时间：2018-01-15 20:12

  本文关键词：玄武岩纤维对低温下钢渣粉混凝土力学性能影响的试验分析　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 钢渣粉 玄武岩纤维 低温 抗压强度 劈裂抗拉强度 养护龄期

【摘要】：目前,随着社会对低碳环保要求的提高,用钢渣粉替代水泥制成的钢渣粉混凝土,以其和易性良好和水化热低等优点受到普遍关注。但是钢渣粉混凝土也存在强度增长慢、早期强度较低、抗裂性差和钢渣粉高掺量时导致混凝土的强度降低幅度较大等问题。我国近半国土在冬季时气温低于零度,对于冬季的工程施工,低温条件下混凝土强度的降低就是一个必须考虑的问题。钢渣粉作为掺和料对混凝土的抗冻性有一定的改善。玄武岩纤维抗拉强度高、耐低温和抗裂性良好等优点,将其与钢渣粉复合掺入改善早期强度为钢渣粉混凝土在寒区的应用打开一条新思路。本文首先研究了玄武岩纤维掺量为3kg/m~3下钢渣粉掺量和养护龄期对玄武岩纤维钢渣粉混凝土压拉性能的影响,得出钢渣粉混凝土的强度增长规律和合适的钢渣粉掺量。在此基础上研究在合适钢渣粉掺量下不同低温养护条件时,不同掺量的玄武岩纤维对钢渣粉混凝土压拉强度的影响。首先,进行了不同龄期下钢渣粉对混凝土压拉强度影响的试验,其中养护龄期分别为7d、14d、28d,钢渣粉掺量为0%、12%、15%、18%、20%。试验结果相较于不掺钢渣粉的混凝土,混凝土掺入钢渣粉后其28d压拉强度与未掺入组基本持平或略有提高,在钢渣粉掺量为15%时达到最优,抗压强度提高了 2.6%,劈裂抗拉强度提高了 9.2%;在养护龄期为14d时,在钢渣粉掺量12%时抗压强度达到最优,提高了 7.5%,劈裂抗拉强度在钢渣粉量20%时达到最优,提高了 4.4%;在养护龄期为7d时,混凝土的压拉强度均随着钢渣粉掺量的增加而降低。通过对不同掺量的钢渣粉混凝土在不同龄期的强度发展规律对比得,玄武岩纤维钢渣粉混凝土早期强度发展较慢,后期强度发展较快,且其28d强度略高或基本持平于不掺钢渣粉混凝土的强度。在此基础上进行了以玄武岩纤维掺量分别为0kg/m~3、2kg/m~3、3kg/m~3、4kg/m~3、5kg/m~3,养护温度为标准养护、-5℃、-10℃、-15℃、-20℃的正交试验,共25组。与各自养护温度下未掺纤维组比较,在养护温度为标准养护和-5℃时,在玄武岩纤维在3kg/m~3时,混凝土强度达到最大,抗压强度分别提高了 3.9%和7.4%,劈裂抗拉强度分别提高了 11.5%和7.8%;在养护温度为-10℃、-15℃和-20℃时,玄武岩纤维为4 kg/m~3时,混凝土强度达到最大,抗压强度分别提高了 8.9%、8.9%和17.9%,劈裂抗拉强度分别提高了 8.9%、10.5%和23.1%。标准养护下未掺入纤维的钢渣粉混凝土强度为38.8MPa。与其相比在低温-5℃、-10℃、-15℃、-20℃养护下掺入玄武岩纤维的混凝土,其最大抗压强度可达100.7%、98.9%、98.2%、98.2%,最大劈裂抗拉强度可达96.9%、94.1%、92.3%、91.3%。试验结果表明:在低温条件下使用的钢渣粉混凝土在掺入玄武岩纤维后,强度得到有效提高,接近标养下的普通钢渣粉混凝土的强度。说明玄武岩纤维可以较好的改善钢渣粉混凝土低温环境下的抗冻能力。
[Abstract]:At present, with the society to improve the requirements of low-carbon environmental protection, steel slag powder instead of cement made of steel slag concrete. Due to the advantages of good compatibility and low hydration heat, steel slag powder concrete also has slow strength growth and low early strength. Poor crack resistance and high content of steel slag powder lead to large reduction of concrete strength. The temperature of nearly half of our country is lower than zero in winter, so the engineering construction in winter is carried out. The reduction of concrete strength at low temperature is a problem that must be considered. Steel slag powder as admixture can improve the frost resistance of concrete to some extent, and the tensile strength of basalt fiber is high. Low temperature resistance and good crack resistance and other advantages. The application of steel slag concrete in cold region is a new way to improve the early strength by adding it to steel slag powder. In this paper, the content and curing age of steel slag powder with basalt fiber content of 3 kg / m ~ (3) are studied firstly. The influence on the compressive and tensile properties of basalt fiber steel slag powder concrete. The strength growth law and the appropriate amount of steel slag powder are obtained. On this basis, the different low temperature curing conditions under the appropriate steel slag powder content are studied. The effect of basalt fiber on compressive tensile strength of steel slag concrete was studied. Firstly, the effect of steel slag powder on compressive tensile strength of concrete was tested at different ages, and the curing age was 7 days or 14 days respectively. At 28 days, the amount of steel slag powder was 0 and 12%. The test results were compared with the concrete without steel slag powder. The compressive tensile strength of concrete mixed with steel slag powder is basically equal to that of unadulterated group for 28 days, and the compressive strength is increased by 2.6% when the content of steel slag powder is 15. Splitting tensile strength increased 9.2%; When the curing age is 14 days, the compressive strength of steel slag powder reaches the optimum when the content of steel slag powder is 12, and increases 7.5. the splitting tensile strength reaches the optimum when the steel slag powder content is 20, and increases 4.4. When the curing age is 7 days, the compressive tensile strength of concrete decreases with the increase of steel slag powder content. The early strength development of basalt fiber steel slag powder concrete is slow and the later strength development is faster. On the basis of this, the basalt fiber content is 0 kg / m ~ 3 ~ 3 kg / m ~ (-1) ~ 3kg / m ~ (-1) ~ 3 ~ (-1) ~ 3kg ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1). The standard curing temperature is -5 鈩，

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