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Energy Absorption Characteristics of PVC Coarse Aggregate Concrete under Impact Load
International Journal of Concrete Structures and Materials ( IF 3.6 ) Pub Date : 2021-05-12 , DOI: 10.1186/s40069-021-00465-w
Shi Hu , Huaming Tang , Shenyao Han

In this paper, polyvinyl chloride (PVC) coarse aggregate with different mixing contents is used to solve the problems of plastic pollution, low energy absorption capacity and poor damage integrity, which provides an important reference for PVC plastic concrete used in the initial support structures of highway tunnels and coal mine roadway. At the same time, the energy absorption characteristics and their relationship under different impact loads are studied, which provides an important reference for predicting the energy absorption characteristics of concrete under other PVC aggregate content or higher impact speed. This study replaced natural coarse aggregate in concrete with different contents and equal volume of well-graded flaky PVC particles obtained by crushing PVC soft board. Also, slump, compression, and splitting strength tests, a free falling low-speed impact test of steel balls and a high-speed impact compression test of split Hopkinson pressure bar (SHPB) were carried out. Results demonstrate that the static and dynamic compressive strength decreases substantially, and the elastic modulus and slump decrease slowly with the increase of the mixing amount of PVC aggregate (0–30%). However, the energy absorption rate under low-speed impact and the specific energy absorption per MPa under high-speed impact increase obviously, indicating that the energy absorption capacity is significantly enhanced. Regardless of the mixing amount of PVC aggregate, greater strain rate can significantly enhance the dynamic compressive strength and the specific energy absorption per MPa. After the uniaxial compression test or the SHPB impact test, the relative integrity of the specimen is positively correlated with the mixing amount of PVC aggregate. In addition, the specimens are seriously damaged with the increase of the impact strain rate. When the PVC aggregate content is 20%, the compressive strength and splitting strength of concrete are 33.8 MPa and 3.26 MPa, respectively, the slump is 165 mm, the energy absorption rate under low-speed impact is 89.5%, the dynamic compressive strength under 0.65 Mpa impact air pressure is 58.77 mpa, and the specific energy absorption value per MPa is 13.33, which meets the requirements of shotcrete used in tunnel, roadway support and other impact loads. There is a linear relationship between the energy absorption characteristics under low-speed impact and high-speed impact. The greater the impact pressure, the larger the slope of the fitting straight line. The slope and intercept of the fitting line also show a good linear relationship with the increase of impact pressure. The conclusions can be used to predict the energy absorption characteristics under different PVC aggregate content or higher-speed impact pressure, which can provide important reference for safer, more economical, and environmental protection engineering structure design.



中文翻译:

冲击载荷下PVC粗骨料混凝土的能量吸收特性

本文采用不同掺量的聚氯乙烯(PVC)粗骨料解决了塑料污染,能量吸收能力低,破坏完整性差的问题,为在初始支撑结构中使用的PVC塑料混凝土提供了重要的参考。公路隧道和煤矿巷道。同时,研究了不同冲击载荷下的能量吸收特性及其相互关系,为预测其他PVC骨料含量或更高冲击速度下混凝土的能量吸收特性提供了重要的参考。这项研究用不同的含量和等体积的通过破碎PVC软板而获得的等比例的片状PVC颗粒代替了混凝土中的天然粗骨料。另外,坍落度,压缩和劈裂强度测试 进行了钢球的自由落体低速冲击试验和剖分霍普金森压力杆(SHPB)的高速冲击压缩试验。结果表明,随着PVC骨料掺混量的增加(0-30%),静,动态抗压强度显着下降,弹性模量和坍落度下降缓慢。然而,低速冲击下的能量吸收率和高速冲击下每MPa的比能量吸收明显增加,表明能量吸收能力得到了显着提高。无论PVC骨料的混合量如何,较大的应变率都可以显着提高动态抗压强度和每MPa的比吸收率。经过单轴压缩测试或SHPB冲击测试后,试样的相对完整性与PVC骨料的混合量呈正相关。另外,随着冲击应变率的增加,试样受到严重破坏。当PVC骨料含量为20%时,混凝土的抗压强度和抗拉强度分别为33.8 MPa和3.26 MPa,坍落度为165 mm,低速冲击下的能量吸收率为89.5%,在低速冲击下的动态抗压强度0.65 Mpa的冲击气压为58.77 mpa,每MPa的比能量吸收值为13.33,满足隧道,巷道支护和其他冲击载荷中所用喷射混凝土的要求。在低速冲击和高速冲击下的能量吸收特性之间存在线性关系。冲击压力越大 拟合直线的斜率越大。随着冲击压力的增加,拟合线的斜率和截距也显示出良好的线性关系。结论可用于预测不同聚氯乙烯含量或较高冲击压力下的能量吸收特性,可为更安全,更经济,更环保的工程结构设计提供重要参考。

更新日期:2021-05-12
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