冻融循环下玄武岩纤维混凝土的耐久性寿命预测

Life prediction of basalt fiber concrete under freeze-thaw cycle

针对我国西北地区混凝土结构在盐冻侵蚀下耐久性降低的问题,选取不同掺量的玄武岩纤维混凝土和普通混凝土进行冻融试验研究,对其在3种冻融工况下的耐久性寿命进行预测。结果表明:清水冻融工况下对混凝土造成的损伤要低于盐冻侵蚀;玄武岩纤维的掺入可以有效地减缓混凝土在盐冻侵蚀作用下力学性能的衰减速率,当纤维掺量达到0.15%时效果最优;纤维的掺入对裂缝的扩张、孔隙的增加等有阻碍作用,使混凝土的抗冻耐久性得到提升;灰色预测和威布尔两种模型的寿命预测结果大致相似,其中灰色预测模型所需样本容量较小,威布尔模型预测结果较为精确。

Aiming at the problem that the durability of concrete structures in northwest China is reduced under salt-frost erosion,the frost resistance of basalt fiber concrete and ordinary concrete with different strength is tested and studied.Based on the change of freeze-thaw medium and cycle times,the durability life of basalt fiber concrete under different dosage and working conditions was predicted.The results show that the damage to concrete caused by freeze-thaw water is lower than that caused by salt-frost erosion.The addition of basalt fiber can effectively slow down the decay rate of mechanical properties of concrete under the action of salt-frost erosion,and the effect is optimal when the fiber content reaches 0.15%.The addition of fibers hinders the expansion of cracks and the increase of pores,thus improving the freezing-resistance durability of concrete.The final results of the two life prediction models are roughly similar.The grey prediction model requires a small sample size,but the Weibull model is more accurate than the grey prediction model in predicting life duration.