不同强度等级混凝土-190℃时受压强度性能试验研究

EXPERIMENTAL STUDY ON COMPRESSIVE BEHAVIOR OF DIFFERENT STRENGTH GRADE CONCRETES EXPOSED TO-190℃

通过5种配合比混凝土的试验,探究了不同强度等级混凝土-190℃超低温下的受压强度性能。结果表明,-190℃时混凝土受压的宏观试验现象较常温明显地不同。破坏时脆性均显著,但破坏形态却基本相同。所有试件混凝土-190℃时的受压强度均显著地提高,但混凝土的强度等级对其影响较大,并且还取决于混凝土的含水率。该次试验的C30和C40混凝土-190℃时受压强度较常温可分别增幅达40%和65%,提高其含水率后竟与C50和C60混凝土增幅相近、达90%以上。根据该次试验结果与已有研究结果给出的不同强度等级混凝土-190℃时受压强度的计算模型,可用于LNG储罐等混凝土结构的设计和安全评估。

The compressive behavior of concrete exposed to -190℃ with different strength grades including C30, C40, C50, and C60 was investigated through experiments with 5 different kinds of mix proportion. The results showed the experimental macro-phenomena of concrete exposed to -190℃ differed greatly from those at normal temperature. The specimens tended to present an obvious brittle failure, and the failure modes of all specimens were alike. The compressive strength of all specimens exposed to -190℃ increased obviously, and the strength grade of concrete had a great influence on its compressive strength. The extent of the increase in concrete compressive strength depended greatly on the water content in the specimen. The compressive strength of concrete exposed to -190℃ with C30 and C40 was increased by 40% and 65%, respectively, and they became similar to those for C50 and C60 and increased to above 190% after their water content in concrete was increased. Based on the experiment results and the existing research results, a predictive model for the compressive strength of different strength grade concrete exposed to -190℃ was proposed and is expected to be applicable for reliable design and evaluation of concrete structures such as LNG tanks.