橡胶改性免蒸压管桩混凝土抗冲击性能研究
发布时间：2018-11-27 18:04
【摘要】：PHC管桩又称预应力高强混凝土管桩,是桩基础建设的一种重要的建筑构件。随着我们国家建筑工业现代化进程的不断推进,人们对于PHC管桩的需求不断增加,对于PHC管桩的性能和标准也在不断提高。目前的免蒸压管桩混凝土的制备,由于省去了传统的高温高压养护的工艺,其抗冲击性能要低于蒸压管桩。而且为了实现免蒸压管桩混凝土的早强特性,配合比中往往加入许多掺合物,如矿渣粉,硅粉,微珠,减水剂等,这些掺合物能够改善管桩混凝土的和易性、提高混凝土的耐久性等优点,但若是直接投入生产,成本往往非常巨大,在尚未知道混凝土性质之前,草率地将新工艺生产的PHC管桩制品投入市场也是十分不明智的。且在工程实例上和科学研究上,免蒸压管桩受冲击破坏率都高于蒸压管桩。所以本研究旨在通过向管桩混凝土中掺入一定量的橡胶粉颗粒,尝试通过橡胶柔性大,变形能力强的特点,改变管桩混凝土的韧性低和抗冲击性能差的缺陷。研究过程中了解熟悉了管桩从材料到成品的整个生产流程。以免蒸压管桩混凝土作为基础混凝土,制作了橡胶粉掺量不同的混凝土试块。所有混凝土试块都与同一批次的管桩在同等条件下搅拌、成型、养护。通过混凝土的静态抗压实验和SHPB压杆冲击实验,研究了橡胶粉对管桩混凝土静态抗压强度的影响和橡胶混凝土的一些力学性能。通过实验结果和理论分析,研究发现橡胶粉对混凝土静态抗压强度的影响主要是由于其改变了混凝土内部结构的粘结界面强度造成的,橡胶混凝土的静态抗压强度会随着橡胶粉掺入量的增加而下降。橡胶混凝土在静态压缩条件下破坏的形态也与普通混凝土有很大的差异。从SHPB压杆冲击实验,研究了橡胶混凝土在高应变率荷载下的性能。在破坏形态上,随着应变率的增加,橡胶混凝土的破坏由裂缝变成粉碎。橡胶混凝土与普通混凝土一样,体现出动态增强效应,其动态抗压强度高于静态抗压强度,其变化的规律与冲击速度和能量有关,也与橡胶掺量密不可分。橡胶粉能够改善混凝土的变形性能,橡胶混凝土破坏时的吸能效果也比普通混凝土要高。这些研究结果对免蒸压管桩性能的研究和橡胶改性混凝土的研究提供了一定的参考。
[Abstract]:PHC pipe pile, also called prestressed high strength concrete pipe pile, is an important building member in pile foundation construction. With the development of modernization of China's construction industry, the demand for PHC pipe pile is increasing, and the performance and standard of PHC pipe pile are also improving. At present, the preparation of non-autoclaved pipe pile concrete is lower than that of autoclaved pipe pile because the traditional high-temperature and high-pressure curing technology is eliminated. And in order to realize the early strength characteristic of the concrete without autoclaved pressure pipe pile, many admixtures, such as slag powder, silica powder, microbeads, water reducer and so on, are often added to the mix ratio. These admixtures can improve the workability of pipe pile concrete. To improve the durability of concrete, however, if the concrete is put into production directly, the cost is very large, and it is very unwise to put the PHC pipe pile products produced by the new technology into the market without knowing the nature of the concrete. In engineering practice and scientific research, the impact failure rate of non-autoclaved pipe pile is higher than that of autoclaved pipe pile. So the purpose of this study is to change the defects of low toughness and poor impact resistance of pipe pile concrete by adding a certain amount of rubber powder particles into the concrete of pipe pile and through the characteristics of large rubber flexibility and strong deformation ability. In the course of the research, we are familiar with the whole production process of pipe pile from material to finished product. In order to avoid autoclaved pipe pile concrete as foundation concrete, concrete test blocks with different rubber powder content were made. All concrete test blocks are mixed, formed and maintained under the same conditions with the same batches of pipe piles. The influence of rubber powder on static compressive strength of pipe pile concrete and some mechanical properties of rubber concrete were studied by static compression test of concrete and impact test of SHPB compression bar. Through the experimental results and theoretical analysis, it is found that the influence of rubber powder on the static compressive strength of concrete is mainly due to the change of the bond strength of the internal structure of concrete. The static compressive strength of rubber concrete decreases with the increase of rubber powder content. The failure pattern of rubber concrete under static compression is also different from that of ordinary concrete. The performance of rubber concrete under high strain rate load was studied by SHPB compression bar impact test. With the increase of strain rate, the failure of rubber concrete changes from crack to comminution. The dynamic compressive strength of rubber concrete is higher than that of static concrete, and its dynamic compressive strength is higher than that of static concrete. The law of change is related to the impact speed and energy, and is closely related to the rubber content. Rubber powder can improve the deformation performance of concrete, and the energy absorption effect of rubber concrete is higher than that of ordinary concrete. These results provide a certain reference for the study of the properties of non-autoclaved pipe piles and the study of rubber-modified concrete.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528
[Abstract]:PHC pipe pile, also called prestressed high strength concrete pipe pile, is an important building member in pile foundation construction. With the development of modernization of China's construction industry, the demand for PHC pipe pile is increasing, and the performance and standard of PHC pipe pile are also improving. At present, the preparation of non-autoclaved pipe pile concrete is lower than that of autoclaved pipe pile because the traditional high-temperature and high-pressure curing technology is eliminated. And in order to realize the early strength characteristic of the concrete without autoclaved pressure pipe pile, many admixtures, such as slag powder, silica powder, microbeads, water reducer and so on, are often added to the mix ratio. These admixtures can improve the workability of pipe pile concrete. To improve the durability of concrete, however, if the concrete is put into production directly, the cost is very large, and it is very unwise to put the PHC pipe pile products produced by the new technology into the market without knowing the nature of the concrete. In engineering practice and scientific research, the impact failure rate of non-autoclaved pipe pile is higher than that of autoclaved pipe pile. So the purpose of this study is to change the defects of low toughness and poor impact resistance of pipe pile concrete by adding a certain amount of rubber powder particles into the concrete of pipe pile and through the characteristics of large rubber flexibility and strong deformation ability. In the course of the research, we are familiar with the whole production process of pipe pile from material to finished product. In order to avoid autoclaved pipe pile concrete as foundation concrete, concrete test blocks with different rubber powder content were made. All concrete test blocks are mixed, formed and maintained under the same conditions with the same batches of pipe piles. The influence of rubber powder on static compressive strength of pipe pile concrete and some mechanical properties of rubber concrete were studied by static compression test of concrete and impact test of SHPB compression bar. Through the experimental results and theoretical analysis, it is found that the influence of rubber powder on the static compressive strength of concrete is mainly due to the change of the bond strength of the internal structure of concrete. The static compressive strength of rubber concrete decreases with the increase of rubber powder content. The failure pattern of rubber concrete under static compression is also different from that of ordinary concrete. The performance of rubber concrete under high strain rate load was studied by SHPB compression bar impact test. With the increase of strain rate, the failure of rubber concrete changes from crack to comminution. The dynamic compressive strength of rubber concrete is higher than that of static concrete, and its dynamic compressive strength is higher than that of static concrete. The law of change is related to the impact speed and energy, and is closely related to the rubber content. Rubber powder can improve the deformation performance of concrete, and the energy absorption effect of rubber concrete is higher than that of ordinary concrete. These results provide a certain reference for the study of the properties of non-autoclaved pipe piles and the study of rubber-modified concrete.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528
【参考文献】
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