Research on mechanical behavior of recycled aggregate concrete after high temperatures |
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| Authors: | CHEN Zongping ZHOU Chunheng LI Yi CHEN Jianjia WU Bo |
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| Affiliation: | 1. College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China；;
2. Key Laboratory of Disaster Prevention and Structural Safety of China Ministry of Education, Guangxi University, Nanning 530004, China；;
3. State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510640, China; |
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| Abstract: | Based on the parameters which were temperature, recycled coarse aggregate replacement percentage, coarse aggregate type and concrete strength, 168 standard prism specimens of recycled aggregate concrete were exposed to different high temperatures, and then subjected to axial compression test. The surface variation and compression failure mode of specimens after exposure to high temperature were observed in the experiment. The mass loss ratio, elasticmodel, axial compressive strength and stress-strain curve were obtained and analyzed through the effect of each parameter variation. Two methods of residual strength assessment, which is based on the mass loss ratio and the highest exposure temperature, for recycled aggregate concrete after elevated temperature were proposed. The test results show that with the increase of temperature, the color of specimens change from steel gray to brown gray, finally to gray. Crack and spalling due to elevated temperature appear on its surface. The mass loss ratio is increased with the increase of temperature, enhancement of replacement percentage and reduction of compressive strength. The influence of temperature for failure mode and mechanical behavior of recycled aggregate concrete after high temperature is most significant. The higher the temperature, the wider the crack band, and the higher of the damage level. With the increase of temperature, the decrease of elasticity modulus is greater than that of peak stress. The influence of high temperature on mechanical behavior of recycled gravel aggregate concrete is more significant than that of recycled pebble aggregate concrete. The change of concrete strength and recycled coarse aggregate replacement percentage has no obvious effect on mechanical behavior of recycled aggregate concrete after high temperature. The method of residual strength assessment is accurate. The calculated axial compressive strength of recycled aggregate concrete after high temperature based on the test agrees well with the measured results. |
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| Keywords: | recycled aggregate concrete after high temperature static test mechanical behavior strength assessment |
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