Study on the mechanical properties of polyurethane (PU) grouting material of different geometric sizes under uniaxial compression
Study on the mechanical properties of polyurethane (PU) grouting material of different geometric sizes under uniaxial compression
复制标题
不同几何尺寸聚氨酯（PU）灌浆材料单轴压缩力学性能研究
DOI：
10.1016/j.conbuildmat.2020.119797
复制
发表时间：
2020-10-30
影响因子：
7.4
通讯作者：
Fang, Hongyuan
中科院分区：
文献类型：
--
作者：
Li, Manjun;Du, Mingrui;Fang, Hongyuan
聚氨酯（PU）作为灌浆材料越来越多地用于基础设施的非开挖修复。聚氨酯材料的抗压强度是达到理想灌浆效果的关键。然而，在单轴压缩试验中，聚氨酯样品的几何尺寸尚未规定，这使得测试结果的通用性较差。在这里，制备具有不同密度和几何尺寸的具有正方形横截面的PU样品。通过扫描电子显微镜（SEM）的PU矩阵的微观形态进行了研究。进行了单轴压缩试验，分析了试样密度、边长（I）、高边长比（H/l）对力学性能的影响。结果表明，聚氨酯微泡的平均当量直径为50-116 μ m，平均偏心率为0.55-0.78。当密度增加时，泡沫变得更小并且更像球形。在单轴载荷作用下，直至发生应变硬化，密度l和H/l的变化对应力随应变的变化规律影响不大。PU灌浆材料的力学性能随密度的增加呈幂函数关系增加。当l或H/l，改变时，低密度PU的力学性能（
Polyurethane (PU) is increasingly adopted as grouting materials in the non-excavation rehabilitation of infrastructures. The compressive strength of PU materials is the key to achieving a desirable grouting effect. However, the geometric sizes of PU samples in the uniaxial compression test are not specified yet, which makes the test results less universal. Here, PU samples with a square cross-section were prepared with different densities and geometric sizes. The micromorphology of the PU matrices was investigated via a scanning electron microscope (SEM). Uniaxial compression tests were conducted, and the effects of density, side length (I), and height to side length ratio (H/l) of the samples on the mechanical properties were analyzed. The results show that micro foams in PU matrices have average equivalent diameters and average eccentricities of 50-116 mu m and 0.55-0.78, respectively. When the density increases, the foams become smaller and more sphere-like. Under the uniaxial load, until strain hardening occurs, both the varied density, l and H/l bring little influence on the variation laws of stress with the strain. The mechanical properties of PU grouting materials increase with the increased density following a power function. When l or H/l, changes, the mechanical properties of low-density PU (