再生保温混凝土冻融循环后基本力学性能研究

发布时间：2018-03-17 01:08

本文选题：再生保温混凝土　切入点：冻融循环　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国新型、快速城镇化建设的需求,在资源节约、环境友好、绿色循坏发展方向的指导下,再生保温混凝土应运而生。由于运用了再生骨料和保温骨料,再生保温混凝土具备解决建筑垃圾、资源重复利用的优势,同时具有轻质、保温、节能、无机、防火的特点,有着进一步深入研究的价值。本文在玻化微珠保温混凝土已有科研成果的基础上,掺入不同比例的再生骨料配合而成再生保温混凝土,研究其在常温下及冻融循环后的基本力学性能,探究经过冻融循环后再生保温混凝土力学性能退化规律,回归分析冻融循环后力学性能理论计算公式,为再生保温混凝土在实际工程的应用实践上提供依据。本文主要研究内容及结论如下:(1)对再生保温混凝土的基本力学性能进行了试验研究,探究了再生粗骨料取代率对其各项基本力学性能的影响分析及破坏特征及机理。(2)开展不同再生骨料取代率、不同冻融循环次数下的冻融循环试验。通过从试块的外部形态、相对动弹性模量、质量损失率以及强度损失率四个方面分析了冻融对混凝土力学性能的影响。得出再生保温混凝土立方体和棱柱体抗压强度、抗拉强度、抗折强度随冻融循环次数变化的定量表达式。(3)通过试验研究可知,随着冻融次数的增加,再生保温混凝土外观逐渐变得粗糙、凹凸不平,表皮剥蚀而酥松,有缺角现象,粗细骨料逐渐显露,裂纹随着数量越来越多,裂纹的宽度也慢慢增大,裂纹的发展方向渐渐向试件内部延伸;由于冻胀作用,试块材料内部水分不断冻结,试块质量先增大,后因冻融循环作用,表面剥蚀,质量因此损失;再生骨料掺入量越大,随着冻融次数的增大,质量损失越大。不同再生骨料取代率下的保温混凝土的强度呈现线性递减;随着冻融次数的增加,再生保温混凝土抗压强度指标退化率先慢后快;劈裂抗拉强度强度指标退化率呈明显陡降趋势,前期显著降低,后呈加剧状态,最后再次快速降低;静力弹性模量变化不明显。
[Abstract]:With the demand of new and rapid urbanization construction in our country, under the guidance of resource saving, environment friendly and green follow the bad developing direction, recycled insulation concrete emerges as the times require. Because of the use of recycled aggregate and thermal insulation aggregate, Recycled insulating concrete has the advantages of solving construction waste and reuse of resources, at the same time, it has the characteristics of light weight, heat preservation, energy saving, inorganic, fire prevention, etc. On the basis of the existing scientific research achievements of vitrified microbead insulation concrete, the recycled insulation concrete is formed by mixing different proportions of recycled aggregate. The basic mechanical properties at room temperature and after freeze-thaw cycle are studied, the degradation law of mechanical properties of regenerated insulating concrete after freeze-thaw cycle is explored, and the formula of theoretical calculation of mechanical properties after freeze-thaw cycle is analyzed by regression analysis. The main contents and conclusions of this paper are as follows: (1) the basic mechanical properties of recycled insulating concrete are studied experimentally. The influence of regenerated coarse aggregate replacement rate on its basic mechanical properties and its failure characteristics and mechanism were investigated. (2) different recycled aggregate replacement rates and freeze-thaw cycles were tested under different freezing and thawing cycles. The effects of freeze-thaw on the mechanical properties of concrete are analyzed from four aspects: relative dynamic modulus of elasticity, mass loss rate and strength loss rate. The compressive strength and tensile strength of recycled insulating concrete cube and prism are obtained. The quantitative expression of flexural strength with the number of freeze-thaw cycles. (3) with the increase of freezing and thawing times, the appearance of recycled insulating concrete becomes rough and uneven, the skin denudates and becomes crisp, and there is a phenomenon of lack of angle. With the increasing number of cracks, the crack width gradually increased, and the development direction of the crack gradually extended to the inside of the specimen. Because of the frost heaving, the moisture in the sample material kept freezing, and the mass of the specimen first increased. As a result of freeze-thaw cycle, surface erosion and mass loss, the more recycled aggregate is added, the greater the mass loss is with the increase of freezing and thawing times. The strength of insulating concrete with different recycled aggregate replacement ratio decreases linearly. With the increase of freeze-thaw times, the degradation of compressive strength index of recycled insulating concrete is first slow and fast, and the degradation rate of splitting tensile strength index shows a steep downward trend, which decreases significantly in the early stage, then intensifies, and then rapidly decreases again. The change of static elastic modulus is not obvious.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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