Methodology on evaluating the compactness of core concrete in CFST serving under low atmospheric pressure over the Qinghai-Tibet Plateau
Chen Zheng1 Chen Ben1 Zheng Jielian1 Liu Jiaping2 Ye Zengxin1 Wu Changjie1 Xu Wen2
1. Key Laboratory of Disaster Prevention and Structural Safety of the Ministry of
Education/Guangxi Key Laboratory of Disaster Prevention and Structural Safety，Guangxi University，Nanning 530004，China;
2. State Key Laboratory of High-Performance Civil Engineering Materials, Nanjing 211103, China
Abstract：This study aims to investigate the effect of low atmospheric pressure on the correlation between concrete compressive strength and penetrating ultrasonic pulse velocity (UPV). Concrete specimens were cast and tested with varying water-to-cement ratio, respectively at the high-altitude (Shannan, Tibet Autonomous Region) and the low-altitude regions (Nanning, Guangxi Autonomous Region). The results show that, concrete specimens made under low atmospheric pressure exhibited 5.8%～38.2% higher compressive strength at 7～56d than the one produced under normal atmospheric pressure. The UPV penetrating through concrete made under low atmospheric pressure was lower as compared to the series of standard atmospheric pressure. Besides, it was found that there existed varying linear correlation between the UPV and the strength of concrete when produced under different atmospheric pressure levels. Given this, a correlation model was established to capture the relationship between UPV, concrete strength and atmospheric pressure. Together with mercury intrusion porosimetry (MIP) test, the numerical simulation revealed that the global UPV penetrating through concrete was dependent upon the UPV at the solid phase and porosity. Thereafter, a computational model was proposed to determine the UPV for solid phase of concrete when producing under varying atmospheric pressure. Eventually, based on the correlation between the UPV and concrete strength alongside the compactness degree, a method to evaluate the compactness of core concrete in concrete filled steel tube (CFST) serving under different atmospheric pressure conditions is proposed.
陈正 陈犇 郑皆连 刘加平 叶增鑫 吴昌杰 徐文. 青藏高原低气压环境下钢管混凝土的核心混凝土密实性评估方法研究[J]. 土木工程学报, 2021, 54(8): 1-13.
Chen Zheng Chen Ben Zheng Jielian Liu Jiaping Ye Zengxin Wu Changjie Xu Wen. Methodology on evaluating the compactness of core concrete in CFST serving under low atmospheric pressure over the Qinghai-Tibet Plateau. 土木工程学报, 2021, 54(8): 1-13.
