掺锂渣再生混凝土梁的受剪性能试验研究

发布时间：2018-02-16 01:14

本文关键词： 锂渣再生混凝土粗骨料基本力学性能梁的受剪性能　出处：《新疆大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着建筑行业工业化、生态化进程的不断深化,社会对于建筑废弃物循环使用的呼声越来越高。由于废弃混凝土的再生利用能同时解决垃圾堆放和资源循环利用两个问题,故对其研究已变成一个热点问题。锂盐在生产的时候会伴随有工业废料锂渣生成,不能得到有效利用,对环境造成污染。根据已有研究可知,将锂渣作为掺合料加入混凝土中,在减少污染的同时,对混凝土部分性能有改善作用。建立在课题组前期对再生混凝土粗骨料及锂渣利用现状研究的基础上,将废弃混凝土及锂渣两者拌合使用后进行分析,在减少污染的同时也能带来一定的社会效益。同时在研究过程中得到的经验教训给后来学者对于掺锂渣再生混凝土开展深层次的分析及在实际工程中的推广使用提供参考。本研究是将乌鲁木齐周边的废弃混凝土分类破碎筛分为粒径在4.75mm 31.5mm间且颗粒级配不间断的骨料,并将掺合料锂渣掺入再生混凝土中,对掺入不同锂渣和取代不同再生粗骨料的受剪梁进行试验分析,同时对伴随梁的混凝土试块的抗折、立方体抗压、抗拉及棱柱体抗压等强度问题进行分析;对受剪试验梁的破坏形态特征及发展过程、跨中弯曲开裂荷载和斜向开裂荷载以及试验梁的受剪承载力和斜裂缝的产生及发展等问题做出相应的分析。经过分析可以发现:锂渣和再生粗骨料的混合使用在一定程度上可以改善混凝土的力学性能及梁的受剪性能。相对于基准混凝土强度,当再生粗骨料替代率为30%、锂渣掺量为20%时,试件立方体抗压、轴心抗压强度可分别提高39.9%、48.22%,当再生粗骨料替代率为50%、锂渣掺量为20%,试件劈裂抗拉和抗折强度可分别提高48.41%、15.77%,且经过分析可知当再生粗骨料替代率为30%、锂渣掺量为20%时整体配比最好。试验梁的破坏过程及破坏形态与普通混凝土梁相似,且符合平截面假定;跨中开裂荷载和受剪承载力在再生粗骨料取代50%锂渣掺入20%时达到最大,相对于普通受剪梁分别提高46.91%、20.48%,并提出适用于试验梁的跨中开裂荷载、斜向开裂荷载及受剪承载力的经验计算式;试验梁裂缝产生及发展与普通混凝土相似,斜裂缝宽度随锂渣掺量不断增大而逐步减小,随再生粗骨料替代率的增加而不断降低,并提出适用于试验梁的斜裂缝宽度计算公式。
[Abstract]:With the industrialization of the construction industry and the deepening of the ecological process, the society is calling for the recycling of construction waste more and more. Because the recycling of waste concrete can simultaneously solve the two problems of garbage stacking and resource recycling, Therefore, the study of lithium salt has become a hot issue. Lithium salt will be accompanied by the production of industrial waste lithium slag, which can not be used effectively and cause pollution to the environment. According to the existing research, lithium slag is added to concrete as admixture. At the same time of reducing pollution, some properties of concrete are improved. On the basis of the research on the utilization of recycled concrete coarse aggregate and lithium slag, the waste concrete and lithium slag are mixed and used. At the same time, the experience and lessons gained in the course of research will give scholars a deep analysis of the recycled concrete with lithium slag and its application in practical engineering. In this study, the waste concrete around Urumqi was classified and sifted into aggregates with a particle size of 4.75 mm or 31.5 mm and uninterrupted gradation. Adding lithium slag into recycled concrete, the shear beam with different lithium slag and replacing different recycled coarse aggregate is tested and analyzed. At the same time, the flexural and cubic compression resistance of concrete test block with beam is analyzed. The tensile strength and the compressive strength of the prism are analyzed, and the failure characteristics and development process of the shear test beam are analyzed. The problems such as bending cracking load and oblique cracking load in span, shear bearing capacity of test beam and the generation and development of inclined crack are analyzed. It can be found that the mixed use of lithium slag and recycled coarse aggregate can be obtained from the analysis of the composite of lithium slag and recycled coarse aggregate. To some extent, the mechanical properties of concrete and the shear behavior of beams can be improved. When the replacement ratio of recycled coarse aggregate is 30 and the amount of lithium slag is 20, the cube of the specimen is compressed. The axial compressive strength can be increased by 39.9% and 48.22%, respectively. When the replacement rate of regenerated coarse aggregate is 50 and the amount of lithium slag is 20, the tensile and flexural strength of the specimens can be increased by 48.41 and 15.77 respectively, and the analysis shows that when the replacement ratio of regenerated coarse aggregate is 30 and the amount of lithium slag is 20%, The failure process and failure pattern of the test beam are similar to that of the ordinary concrete beam. And it accords with the assumption of plane section that the crack load and shear capacity in span reach the maximum when regenerated coarse aggregate replaces 50% lithium slag and 20%, and increases 46.91 and 20.48 respectively compared with ordinary shear beam, and puts forward the crack load in the span suitable for test beam. The empirical formula for calculating the oblique cracking load and shear capacity, the crack generation and development of the test beam are similar to that of the ordinary concrete, the width of the oblique crack decreases gradually with the increase of lithium slag content, and decreases with the increase of the replacement ratio of recycled coarse aggregate. A formula for calculating the width of slant crack is presented.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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