水泥稳定再生集料的性能及设计研究

发布时间：2018-08-06 16:45

【摘要】：中国正处于建设高峰期，每年产生大量废弃混凝土；另外公路建设特别是路面建设需要消耗大量优质碎石。在路面建设中利用部分建筑垃圾不但能够缓解天然集料紧缺的情况，同时也有助于解决建筑垃圾的处理问题，起到一箭双雕的作用。本论文针对废旧混凝土再生集料及在水泥稳定基层中的应用展开研究，从再生骨料的制备、强化及性能评价，水泥稳定再生集料基层材料的组成设计方法、性能评价及强度标准展开研究，，不仅能为全面推广再生集料的应用提供理论支撑，而且会取得良好的经济效益、社会效益和环境效益。论文首先测试了再生集料的吸水率、压碎值、密度等物理力学性能，并借助SEM图像观测其微观结构，结果表明再生骨料存在空隙和微裂缝，导致其吸水率和压碎值偏高、密度和强度偏低；为提高再生集料的技术性能，需要采用强化措施提高其性能。其次，利用洛杉矶磨耗仪和化学试剂分别对再生集料进行物理和化学强化，通过测试强化后的再生集料的物理力学指标来评价强化效果。10个钢球、转动400圈可以使再生集料的压碎值降低到22.9%、吸水率降低到4.2%；加入活化剂后，再生集料的大部分孔隙被有效封堵，导致降低再生集料的压碎值和吸水率；有机硅树脂的活化效果优于钛酸酯偶联剂及硅烷偶联剂，其最佳剂量为3.77%；经最佳剂量的有机硅树脂活化后的再生集料的压碎值降低到19%、吸水率降低到2%以下。推荐了化学活化的工艺，包括拌合时间、养护时间与温度。再次，配置再生集料掺配率为0%、30%、60%、100%的水泥稳定再生集料，按水泥剂量为4%和5%成型各种试件，测试水泥稳定再生集料的压实特性、强度特性、刚度特性、抗冻性和收缩特性，并分析其影响因素，结果表明水泥稳定再生集料满足道路使用的要求。最后，采用Bisar软件计算高速公路和二级公路两种典型路面结构的力学响应，并推荐水泥稳定再生集料基层的合理模量，并结合水泥稳定再生集料90d模量和7d强度的关系模型，推荐了水泥稳定再生集料的7d强度设计标准：二级公路为2.5~3.178MPa、高速公路为3.5~3.938MPa。
[Abstract]:China is in the peak of construction, producing a large number of waste concrete every year; in addition, highway construction, especially pavement construction, needs to consume a large amount of high-quality gravel. The use of some construction garbage in pavement construction can not only alleviate the shortage of natural aggregate, but also help to solve the problem of disposal of construction waste, and play a role of killing two birds with one stone. In this paper, the recycled aggregate of waste concrete and its application in cement stabilized base are studied, including the preparation, strengthening and performance evaluation of recycled aggregate, and the composition design method of cement stabilized recycled aggregate base material. The research on performance evaluation and strength standard can not only provide theoretical support for the comprehensive application of recycled aggregate, but also obtain good economic, social and environmental benefits. Firstly, the physical and mechanical properties of recycled aggregate, such as water absorption, crushing value, density and so on, are tested. The microstructure of recycled aggregate is observed by means of SEM image. The results show that there are voids and micro-cracks in recycled aggregate, which results in high water absorption and crushing value. In order to improve the technical performance of recycled aggregate, strengthening measures should be adopted to improve its performance. Secondly, the physical and chemical strengthening of recycled aggregate was carried out by means of Los Angeles wear tester and chemical reagent respectively, and 10 steel balls were evaluated by testing the physical and mechanical indexes of the reinforced recycled aggregate. Rotation of 400 circles can reduce the crushing value of recycled aggregate to 22.9 and the water absorption to 4.2. After adding activator, most of the pores of recycled aggregate are effectively blocked, which leads to the reduction of crushing value and water absorption of recycled aggregate. The activation effect of organosilicone resin is better than that of titanate coupling agent and silane coupling agent, and the optimum dosage is 3.77, and the crushing value of regenerated aggregate is reduced to 19%, and the water absorption is reduced to less than 2%. The process of chemical activation is recommended, including mixing time, curing time and temperature. Thirdly, the cement stabilized recycled aggregates with a ratio of 0% to 30% and 100% of the recycled aggregate are allocated to form various specimens according to the cement dosage of 4% and 5%. The compaction, strength, stiffness, frost resistance and shrinkage characteristics of the cement stabilized recycled aggregate are tested. The results show that cement stabilized recycled aggregate meets the requirements of road use. Finally, the mechanical response of two typical pavement structures of expressway and second-grade highway is calculated by Bisar software, and the reasonable modulus of cement stabilized recycled aggregate base is recommended, and the relationship model between 90 d modulus and 7 d strength of cement stabilized recycled aggregate is proposed. The design standard of 7 d strength of cement stabilized recycled aggregate is recommended as follows: the second grade highway is 2.5 ~ 3.178 MPa, and the expressway is 3.5 ~ 3.938 MPa.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

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