高频振捣对道路工程混凝土结构物抗冻性影响的研究

Effects of High-frequency Vibration on Frost Resistance of Road Concrete Structure

为研究高频振捣对混凝土抗冻性的影响,采用先进的硬化混凝土气泡结构测试设备,通过测定硬化混凝土的气泡特征参数随高频振捣时间增加的变化情况,研究了高频振捣对混凝土抗冻性的影响规律。试验结果表明,经适当高频振捣后,虽然混凝土的含气量有较大损失,但其气泡比表面积增大,气泡间隔系数变化不大。随高频振捣时间的增加,硬化混凝土中气泡总数和小气泡数(直径小于120μm)会出现峰值,而后急剧减少。高频振捣的时间控制在合理范围内,有利于改善引气混凝土的气泡结构,不会对其抗冻性产生不利影响。

To study effects of high,frequency vibration on frost resistance of road concrete, advanced air void analyzer was used to measure the variation of air void parameters of hardened air-entrained concrete with different high-frequency vibration times. The results show that （1） although the air content in concrete deceases greatly after high-frequency vibration, the specific surface area of air bubbles increases and the spacing factor has no great changes at the same time; （2） as the time of high-frequency vibration increase, the number of air bubbles,especially the tiny air bubbles （less than 120 μm） in concrete will reach a peak and then decrease.Therefore, as long as the time of high-frequency vibration is appropriately controlled, the air void distribution of concrete can be improved and has no negative effects on the frost resistance of concrete.