硅粉橡胶纤维再生混凝土轴压及断裂性能研究

发布时间：2018-03-08 06:09

本文选题：再生混凝土　切入点：橡胶颗粒　出处：《广东工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着中国经济的发展,每年都会制造大量的固体废弃物,如废旧橡胶和大量由于拆迁和地震等原因而产生的建筑垃圾。如何有效循环利用这些固体废弃物,既减轻环境污染,又节省原材料的消耗,是城市可持续发展的热点研究课题之一。本研究拟以再生废旧的橡胶和混凝土为目的,通过掺入硅粉和纤维,生成一种新型的环保建筑材料—硅粉橡胶纤维再生混凝土(简称SRSRAC),通过实施一系列的轴压和断裂试验,探讨该类新型混凝土的抗压和断裂性能。本文的主要研究内容和结论如下：(1)以环保、节能、循环利用为目标,利用废旧混凝土取代粗骨料、橡胶颗粒替代细骨料,通过内掺或外掺硅粉以及掺入纤维,在大量试验研究的基础上,成功地研发了一种新型再生环保混凝土材料(SRSRAC)。研究结果表明,该类新材料中具有优良的力学性能,而且符合国家节能减排的发展方向；硅粉与钢纤维显现优良的耦合作用,能明显提高橡胶再生混凝土的抗压和断裂性能。(2)以硅粉掺量和掺入方式(内掺0%,5%,10%和外掺3%)、橡胶掺量(0%、5%、10%、15%和20%)以及纤维种类(钢纤维和聚丙烯纤维)为变量,制备了29组共87个SRSRAC圆柱体试件(150mm × 300mm)。通过实施轴压试验,研究了各变量对SRSRAC的抗压强度、弹性模量、韧性、应力应变关系等影响规律。研究结果表明,硅粉能有效增强天然和再生混凝土的抗压强度,但对于SRSRAC,外掺3%或内掺5%以下掺量的硅粉并不能明显改善其抗压性能；钢纤维或聚丙烯纤维可以增强混凝土的耗能能力,与钢纤维相比,聚丙烯纤维的掺入能提供更高的抗压强度；综合考虑SRSRAC的抗压指标,钢纤维掺量为1%、内掺硅粉10%、橡胶掺量为5%的SRSRAC可获得相对较优的抗压性能。(3)制备了19组57个尺寸为100mm × 100mm × 515mm的SRSRAC小梁试件,通过实施进行三点弯曲试验,测定了SRSRAC的荷载—挠度曲线、荷载—裂缝尖端张开口位移(CMOD)曲线。在此基础上,计算出SRSRAC的断裂能、起裂韧度和失稳断裂韧度,并探讨了硅粉掺入方式和橡胶掺量对SRSRAC断裂性能的影响规律。研究结果表明：随着橡胶掺量的增加,SRSRAC断裂能呈现先增后减的趋势,其断裂韧度呈下降趋势,5%-10%为SRSRAC抗断裂性能的最优橡胶掺量；与聚丙烯纤维相比,钢纤维和硅粉的复掺能更有效提高混凝土的断裂性能；随着硅粉掺量的增加,钢纤维混凝土的断裂性能显著提高,使用外掺3%硅粉的方法能取得与内掺10%硅粉相同的改性效果。(4)基于SRSRAC的轴压与断裂实验,探索了SRSRAC的轴压和断裂破坏机理。研究发现：硅粉能增强再生混凝土的密实性,提高钢纤维与再生混凝土的粘结作用；SRSRAC在轴压过程中,橡胶的掺入能较好减缓裂纹尖端处应力集中,钢纤维则起到阻裂作用；SRSRAC在断裂过程中,裂缝横穿粗骨料,钢纤维被拔出,混凝土开裂后应力主要是由钢纤维承担,其裂缝发展分为起裂,发展和失稳三个阶段。
[Abstract]:With the development of China's economy, a large amount of solid waste is produced every year, such as waste rubber and large quantities of construction waste caused by demolition and earthquake. How to recycle these solid wastes effectively will reduce environmental pollution. Saving the consumption of raw materials is one of the hot research topics in the sustainable development of cities. This study aims to regenerate waste rubber and concrete by adding silica fume and fiber. To produce a new type of environmentally friendly building material, silicone rubber fiber recycled concrete (SRSRACU), through a series of axial compression and fracture tests. The main contents and conclusions of this paper are as follows: (1) aiming at environmental protection, energy saving and recycling, waste concrete is used to replace coarse aggregate and rubber particle to replace fine aggregate. On the basis of a large number of experimental studies, a new type of recycled environmental protection concrete material, SRSRAC, was successfully developed by doping silica fume and fiber. The results show that the new material has excellent mechanical properties. And it is in line with the development direction of national energy saving and emission reduction. Silicon fume and steel fiber show excellent coupling effect. It can significantly improve the compressive and fracture properties of recycled rubber concrete. It takes the amount of silica powder and the way in which it is mixed (10% with 0% and 3% with outside) as variables, and the type of fiber (steel fiber and polypropylene fiber) and the type of fiber (steel fiber and polypropylene fiber), as well as the quantity of rubber, 10%, 10%, 10%, and 20%, as well as the type of fiber (steel fiber and polypropylene fiber). A total of 87 SRSRAC cylindrical specimens of 29 groups were prepared. The effects of various variables on the compressive strength, elastic modulus, toughness and stress-strain relationship of SRSRAC were studied by axial compression test. Silica fume can effectively enhance the compressive strength of natural and recycled concrete, but for SRSRAC, silicon powder mixed with 3% or less than 5% can not obviously improve its compressive performance. Steel fiber or polypropylene fiber can enhance the energy dissipation ability of concrete. Compared with steel fiber, polypropylene fiber can provide higher compressive strength. 19 groups of SRSRAC trabeculae with 100mm 脳 100mm 脳 515mm in size were prepared by SRSRAC with 5% rubber content and 10 steel fibers with silicon fume. The results showed that 19 groups of SRSRAC trabeculae with a size of 100mm 脳 100mm 脳 515mm were subjected to three-point bending test. The load-deflection curve and load-crack tip opening displacement curve of SRSRAC were measured. The fracture energy, initial fracture toughness and unstable fracture toughness of SRSRAC were calculated. The effect of silicon powder and rubber content on the fracture properties of SRSRAC was discussed. The results showed that the fracture energy of SRSRAC increased first and then decreased with the increase of rubber content. The fracture toughness shows a downward trend that -10% is the best rubber content of SRSRAC fracture resistance. Compared with polypropylene fiber, the co-addition of steel fiber and silica fume can improve the fracture property of concrete more effectively. The fracture properties of steel fiber reinforced concrete (SFRC) have been greatly improved. The method of adding 3% silica fume can achieve the same modification effect as that of 10% silica fume.) the axial compression and fracture experiments based on SRSRAC are carried out. The mechanism of axial compression and fracture failure of SRSRAC is explored. It is found that silicon powder can enhance the compactness of recycled concrete and improve the bond between steel fiber and recycled concrete. The addition of rubber can reduce the stress concentration at the crack tip, while the steel fiber can prevent the crack. In the process of fracture, the cracks cross the coarse aggregate, the steel fiber is pulled out, and the stress after the concrete cracking is mainly borne by the steel fiber. The fracture development can be divided into three stages: initiation, development and instability.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU528

【相似文献】