原位加载下橡胶砂浆断裂的可视化和量化分析

1)中国地震局工程力学研究所,中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨 150080; 2)深圳大学土木与交通工程学院,广东省滨海土木工程耐久性重点实验室,广东深圳518060

建筑材料; 橡胶砂浆; 三维可视化; X射线微观层析成像; 裂缝发展; 图像处理

Visualization and quantitative fracture analysis of rubber mortar under in-situ loading
ZHANG Jianchao1, 2, PENG Shaocheng2, KUANG Chuan2, WENG Jianwu2, DONG Biqin2, HONG Shuxian2, and XING Feng1, 2

1)Institute of Engineering Mechanics, Key Laboratory of Earthquake Engineering and Engineering Vibration, China Earthquake Administration, Harbin 150080, Heilongjiang Province, P.R.China2)College of Civil and Transportation Engineering, Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P.R.China

building materials; rubber mortar; 3D-visualization; X-ray micro-computed tomography; crack propagation; image processing

DOI: 10.3724/SP.J.1249.2021.02144

备注

为提高材料的延展性,经常在水泥基材料中加入橡胶,但橡胶-水泥界面会产生更多的初始缺陷,由X射线微观层析成像技术得到的三维图像更加复杂,导致以全阈值法为主的传统方法不再适用于对内部三维裂缝进行分析.提出一种改进的图像处理方法,能够准确识别介观裂缝,完成孔和裂缝的分离.采用X射线层析成像原位观测技术对不同质量分数的橡胶砂浆进行测试,通过该方法识别并分离孔和裂缝,得到裂缝发展的可视化过程,分析橡胶加入对裂缝形成的影响.定量分析表明,该方法相比传统方法,能更好地识别介观裂缝,具有更高的精度; 由于橡胶的掺入,橡胶砂浆内部产生更多的初始裂缝,但增加了试样整体对输入能量的吸收,使受压破坏时的大裂缝数量和总裂缝体积减小,与未掺入橡胶的试样相比,橡胶质量分数为5%和10%的试样总裂缝体积分别减小30%和45%左右.

In order to improve the ductilityof cement-based materials, rubber is often added to cement-based materials. But the rubber-cement interface will introduce more initial defects, and make the three dimensional images obtained by the X-ray micro-computed tomography(X-ray μCT)technology more complex, and finally,which leads to the full threshold method no longer applicable to analysis of the internal three-dimensional cracks.This paper presents an improved image processing method, which can accurately identify mesoscopic cracks and achieve the separation of pores and cracks. In order to verify this method, X-ray computed tomography(XCT)in-situ observation technology is used to obtain the crack formation of rubber mortar with different replacement ratios. Pores and cracks are well identified and separated by this method. Quantitative analysis shows that the new method has higher accuracy and better identification of mesoscopic cracks than traditional methods. Due to the incorporation of rubber, there are more initial cracks in the rubber mortar, but the rubber will improve the overall absorption of the input energy of the sample, resulting in a decrease in the number of large cracks and the total crack volume when the specimen is failure.Compared with the sample without rubber content, the total crack volume of the sample with 5% and 10% mass fraction of rubber decreases by 30% and 45%, respectively.

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