青藏高原地区纤维混凝土抗冻耐久性试验与损伤模型研究

Frost Resistance Durability and Damage Model of Fiber Concrete in Tibet Plateau Area

为研究青藏高原环境条件下不同纤维混凝土的抗冻耐久性及冻融损伤演化规律,本研究依托西藏那曲地区某混凝土道路工程,对普通纤维混凝土(NC)、冲磨纤维混凝土(CM)以及膨胀纤维混凝土(PZ)进行了冻融循环试验和相关力学测试,在试验研究的基础上,提出了适用于高原低气压环境下的冻融损伤模型。研究结果表明,从冻融循环试验结果来看,冲磨纤维混凝土(CM)抗冻耐久性最佳,三种纤维混凝土抗冻耐久性排序为CM>NC>PZ。针对本文建立的冻融损伤模型和基于该模型的抗折强度预测方程,采用青藏高原地区某高速工程项目的高寒引气混凝土测试数据进行了验证,冻融后的抗折强度试验值与预测值变化趋势相近且基本吻合。因此,本文建立的青藏高原抗折强度冻融损伤模型是合理且可行的。

In order to investigate the frost resistance durability and evolution law of freeze-thaw damage on different fiber concrete under environmental conditions of the Tibet Plateau area,this paper relies on a concrete road project in the Naqu area of Tibet,the freeze-thaw cycle test and related mechanical tests were conducted on ordinary fiber concrete(NC),abrasion fiber concrete(CM)and expansive fiber concrete(PZ).On the basis of the experimental study,a freeze-thaw damage model was established under low pressure environment of the plateau.The results show that abrasion fiber concrete(CM)has the best frost resistance durability based on the results of freeze-thaw cycle test,while the three kinds of fiber concrete are ranked as CM>NC>PZ in terms of frost resistance durability.According to the freeze-thaw damage model and the predicted flexural strength equation based on the model which are established in this paper,the test data of high cold air-entraining concrete from a high-speed project in the Tibet Plateau area are used for verification.It is found that the trend of the test values of flexural strength after freeze-thaw cycles are similar and coincided with the predicted values.Therefore,the freeze-thaw damage model for the flexural strength of the Tibet Plateau which is established in this paper can be probably reasonable and feasible.