轻骨料对自密实混凝土力学性能的影响

发布时间：2018-01-28 11:34

本文关键词： 自密实混凝土陶粒橡胶颗粒 EPS颗粒工作性抗压强度动态弹性模量阻尼比　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：现代社会不仅人类活动更加频繁,而且地震等自然灾害频发,因此,研发具有良好静动态力学特性的工程结构材料成为国内外相关学者关注的重要焦点之一。本文在综合考虑轻骨料的特性以及自密实混凝土的自密实成型特点,并结合相关国内外研究现状的基础上,通过大量的试验,较系统地研究自密实混凝土在不同轻骨料体系(陶粒、橡胶颗粒、EPS颗粒单掺、两两双掺或三掺复合)下的工作性能、抗压强度、动态弹性模量、动态剪切模量、动态泊松比以及阻尼比的性能,同时分析掺量与强度及动弹模量之间相关性,强度与动弹模量以及阻尼比之间的相关性,试图为研发具有优异工作性和良好动态力学性能的新型水泥基材料提供技术基础。试验研究及相关计算分析结果表明,(1)本文所选用的陶粒、橡胶颗粒以及EPS颗粒分别对新拌自密实混凝土工作性有不同的影响。当陶粒、橡胶颗粒和EPS颗粒两两复合或者三者复合时,通过对减水剂和纤维素醚的调整,能较好地保持拌合物的“自密实性”。(2)掺轻骨料自密实混凝土的28天龄期强度下降率与掺量线性正相关。在相同掺量条件下,橡胶颗粒与EPS颗粒对自密实混凝土抗压强度的降低效应基本相似,而掺陶粒对自密实混凝土的强度降低率更小。陶粒、橡胶颗粒与EPS颗粒三掺对自密实混凝土强度的效应有较好的协同作用效应,同等掺量情况下,三掺自密实混凝土的强度较其他轻骨料单掺和双掺的更高。(3)各掺轻骨料体系下的自密实混凝土动态弹性模量、振动基频、剪切模量随其掺量的增加而降低,其动态弹性模量降低率与掺量线性正相关；不论哪种掺轻骨体系,其强度与动态弹性模量之间都为显著线性相关,但不同骨料单掺下自密实混凝土的动弹模降低的幅度不同。(4)各掺轻骨料体系下的自密实混凝土泊松比不随龄期和掺量变化,基本维持在0.25±0.02范围内波动。(5)自密实混凝土阻尼比在前40个振动循环周期内,随振动循环次数增多而急剧降低。直到40个振动循环以后,才逐渐趋于平缓稳定。各掺轻骨料自密实混凝土28天阻尼比较7天阻尼比明显下降。同龄期下,各轻骨料掺量对阻尼比的影响因骨料品种不同而不同。自密实混凝土阻尼比随强度增加而下降,但两者的线性相关性较差。
[Abstract]:Modern society not only more frequent human activities, and earthquakes and other natural disasters, so. Research and development of engineering structural materials with good static and dynamic mechanical properties has become one of the most important concerns of scholars at home and abroad. In this paper, the characteristics of lightweight aggregate and self-compacting concrete are considered comprehensively. On the basis of the research status at home and abroad, through a large number of experiments, the self-compacting concrete in different lightweight aggregate systems (ceramsite, rubber particles EPS particles) is studied. The properties of working performance, compressive strength, dynamic elastic modulus, dynamic shear modulus, dynamic Poisson's ratio and damping ratio were analyzed. The correlation between strength and dynamic modulus and damping ratio is an attempt to provide a technical basis for the development of new cement-based materials with excellent workability and good dynamic mechanical properties. Experimental study and correlation analysis results show that the ceramic particles, rubber particles and EPS particles selected in this paper have different effects on the workability of freshly mixed self-compacting concrete. When rubber particles and EPS particles are mixed in two or three, the water reducing agent and cellulose ether are adjusted. The decrease rate of 28 days age strength of lightweight aggregate self-compacting concrete is positively correlated with the content of the concrete. The reduction effect of rubber particles and EPS particles on the compressive strength of self-compacting concrete is basically similar, while the decrease rate of the strength of self-compacting concrete with ceramsite particles is even smaller. The effect of rubber particles and EPS particles on the strength of self-compacting concrete has a good synergistic effect. (3) the strength of self-compacting concrete is higher than that of other lightweight aggregate single and double admixture.) the dynamic elastic modulus and vibration fundamental frequency of self-compacting concrete are higher than those of other lightweight aggregate systems. The shear modulus decreases with the increase of its content, and the decreasing rate of dynamic elastic modulus is positively correlated with its content. There is a significant linear correlation between the strength and the dynamic elastic modulus of any kind of light bone system. However, the reduction range of dynamic elastic modulus of self-compacting concrete with different aggregate is different. 4) Poisson's ratio of self-compacting concrete does not change with age and amount of addition. The damping ratio of self-compacting concrete is maintained in the range of 0.25 卤0.02. The damping ratio of self-compacting concrete is within the first 40 cycles of vibration cycle. The damping ratio of self-compacting concrete with lightweight aggregate in 28 days is obviously lower than that in 7 days. At the same age, the damping ratio of self-compacting concrete decreases obviously. The damping ratio of self-compacting concrete decreases with the increase of strength, but the linear correlation between them is poor.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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