钢纤维对混凝土抗冻耐久性影响的研究

INVESTIGATION ON THE FROST DURABILITY OF CONCRETE REINFORCED WITH STEEL FIBER

为研究钢纤维对混凝土抗冻性能的影响,制备了4种钢纤维混凝土试件,并开展了钢纤维混凝土快速冻融循环试验和冻融作用后的毛细吸水试验。分析了相对动弹性模量,累积吸水量和毛细吸水系数等指标的变化规律。引入Weibull分布,建立了混凝土冻融损伤量与冻融循环次数间的概率模型;通过累积吸水量和毛细吸水系数来表征冻融循环作用后基体的耐久性。结果表明钢纤维的加入可延缓混凝土动弹性模量的损失,显著提高其抗冻性能。钢纤维混凝土的冻融损伤与冻融循环次数的关系符合Weibull分布;冻融循环作用后,混凝土的累积吸水量增大,初始阶段的毛细吸水系数提高,毛细吸水能力显著增强,钢纤维的加入可明显降低基体的水分传输能力,提高其抗冻耐久性。

To investigate the effect of steel fiber on the frost resistance of concrete, four specimens of steel fiber reinforced concrete were made, and the rapid freeze-thaw cycle test of steel fiber reinforced concrete was carried out. The dynamic modulus of elasticity, amount of absorbed water, and the coefficient of capillary water absorption of the matrix were analyzed. The probability model between frost damage of the steel fiber reinforced concrete and the number of freeze-thaw cycles was established with the Weibull distribution. The amount of absorbed water and the coefficient of the capillary water absorption were adopted to characterize the durability of the matrix after freeze-thaw cycles. The results showed that the addition of steel fiber can reduce loss of dynamic modulus of elasticity and enhance the frost performance of the matrix. The relationship between the frost damage of steel fiber concrete and the number of freeze-thaw cycles conformed to the Weibull distribution. After the freeze-thaw cycles,the amount of absorbed water and the coefficient of capillary water absorption of the matrix increased noticeably. The capillary water absorption capacity of the concrete without any reinforcement was improved significantly,and water transport capacity reduced with the increasing of the steel fiber dosage. The durability of the concrete can be improved by addition of steel fiber.