高品质再生混凝土骨料剔选技术的研究

发布时间：2018-02-19 21:38

本文关键词： 微波再生粗骨料再生混凝土力学性能破坏形态　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着土木工程领域快速发展,大量建筑垃圾应运而生,对环境和生活造成了严重的影响,为解决这些建筑垃圾资源化再利用问题,提出一些变废为宝理念,但现有技术不够完善,存在剔选出的骨料品质比较差,二次改性成本高等缺点,使得再生混凝土不能广泛运用,现急需提出一种高品质再生混凝土骨料剔选技术,以推动再生混凝土在实际工程中的应用。本文主要采用试验研究方法,利用微波辅助机械剔选技术对废弃混凝土块进行处理,得到高品质再生粗骨料,分别从宏观和细观两方面对其力学性能进行研究,然后配制成再生混凝土,研究其抗压性能和破坏形态。主要内容和结论如下:(1)从粗骨料和砂浆体介电常数不同和粗骨料与砂浆体之间界面弱化原理这两方面进行研究微波辅助机械剔选废弃混凝土块原理,最终得出本试验粗骨料和砂浆体两种材料之间粘结假说属于水泥浆体收缩假说。(2)以900W功率的微波照射不同来源废弃混凝土块,得出最佳照射参数取值范围;通过热成像试验研究,分析废弃混凝土块表面和内部温度分布规律,探讨温度对粗骨料损伤程度;将剔选出的高品质再生粗骨料与天然粗骨料和其它剔选工艺得到的再生粗骨料的力学性能进行对比,说明微波辅助机械剔选工艺的优越性;通过电镜扫描试验,从细观角度分析再生粗骨料的损伤程度,说明微波辅助机械工艺剔选废弃混凝土块得到的的粗骨料具有高品质特性。(3)对普通混凝土和再生混凝土抗压强度和破坏形态进行研究,从试验结果、损伤力学和断裂力学三个角度进行分析,得出再生混凝土和普通混凝土具有类似抗压强度和破坏形式,先后经历弹性阶段、微裂纹产生阶段、微裂纹发展阶段和破坏阶段,二者主要破坏形式都是砂浆体破坏,伴随着粗骨料和砂浆体界面少量破坏和表层混凝上剥落。
[Abstract]:With the rapid development of civil engineering field, a large number of construction waste emerged as the times require, which has a serious impact on the environment and life. In order to solve the problem of recycling construction waste, some ideas of transforming waste into treasure are put forward. But the existing technology is not perfect, the quality of the selected aggregate is poor, the cost of secondary modification is high, so recycled concrete can not be widely used, so it is urgent to put forward a technology of selecting high quality recycled concrete aggregate. In order to promote the application of recycled concrete in practical engineering, this paper mainly adopts the method of experimental research, using microwave assisted mechanical picking technology to treat the waste concrete block, and obtains high quality recycled coarse aggregate. The mechanical properties of the concrete were studied from macroscopic and meso aspects respectively, and then the recycled concrete was prepared. The main contents and conclusions are as follows: (1) from the aspects of different dielectric constants of coarse aggregate and mortar and the principle of interface weakening between coarse aggregate and mortar, microwave assisted mechanical selection of waste is studied. The principle of abandoning concrete blocks, Finally, it is concluded that the bonding hypothesis between coarse aggregate and mortar belongs to the constriction hypothesis of cement paste. The temperature distribution on the surface and inside of the abandoned concrete block is analyzed by thermal imaging test, and the damage degree of coarse aggregate caused by temperature is discussed. Comparing the mechanical properties of high quality recycled coarse aggregate with that obtained by natural coarse aggregate and other weeding processes, the superiority of microwave assisted mechanical sorting process is demonstrated. The damage degree of recycled coarse aggregate is analyzed from the view of meso. It is shown that the coarse aggregate obtained by microwave assisted mechanical technology is of high quality. The compressive strength and failure form of ordinary concrete and recycled concrete are studied. From the test results, damage mechanics and fracture mechanics, it is concluded that recycled concrete and ordinary concrete have similar compressive strength and failure form, which have experienced elastic stage and microcrack generation stage. The main failure forms of microcracks are mortar failure, accompanied by a small amount of damage at the interface between coarse aggregate and mortar and the surface coagulation exfoliation.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U414

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