考虑裂缝存在的水泥混凝土性能劣化试验

发布时间：2018-04-07 14:56

本文选题：道路工程　切入点：水泥混凝土　出处：《公路》2016年11期

【摘要】：为研究车辆荷载、冻融循环和干湿循环作用下水泥混凝土性能劣化机理,并分析裂缝的存在对混凝土性能劣化的影响,对带有裂缝和不带裂缝的混凝土进行加速加载、干湿循环和冻融循环试验,得到试件的相对动弹模量、质量损失及强度的变化,对混凝土性能劣化机理进行研究。试验结果表明:车辆荷载反复作用下水泥混凝土性能劣化不明显,但裂缝的存在使混凝土抗压强度明显降低;干湿循环作用下混凝土性能劣化明显,56次干湿循环作用下混凝土抗压强度降低20%,裂缝的存在对混凝土性能劣化影响不大;冻融循环作用下混凝土性能劣化尤为突出,150次冻融循环作用下不带裂缝和带有裂缝的混凝土弯拉强度分别降低48.3%和52.3%。可见,冻融循环和干湿循环作用是水泥混凝土性能劣化的主要原因,裂缝的存在并未加速混凝土性能的劣化,但裂缝的存在使水分更易进入路面结构内部,并使路面全深范围内的混凝土经受干湿循环和冻融循环作用,车辆荷载的疲劳作用使劣化的路面混凝土加速开裂。
[Abstract]:In order to study the performance deterioration mechanism of cement concrete under vehicle load, freeze-thaw cycle and dry-wet cycle, and analyze the influence of cracks on the performance deterioration of concrete, accelerate the loading of concrete with and without cracks.The relative dynamic modulus, mass loss and strength of the specimens were obtained by dry and wet cycle and freeze-thaw cycle tests. The deterioration mechanism of concrete performance was studied.The test results show that the performance of cement concrete is not obvious under the repeated action of vehicle load, but the compressive strength of concrete is obviously reduced by the existence of cracks.Under the action of dry-wet cycle, the compressive strength of concrete decreases by 20% under the action of 56 times of dry and wet cycles, and the existence of cracks has little effect on the deterioration of concrete performance.Under the action of freeze-thaw cycle, the bending tensile strength of concrete without crack and with crack is decreased by 48.3% and 52.3%, respectively.It can be seen that freeze-thaw cycle and dry-wet cycle are the main reasons for the deterioration of cement concrete performance. The existence of cracks does not accelerate the deterioration of concrete performance, but the existence of cracks makes it easier for moisture to enter the pavement structure.The concrete in the whole depth of pavement is subjected to dry-wet cycle and freeze-thaw cycle, and the fatigue effect of vehicle load accelerates the cracking of the deteriorated pavement concrete.
【作者单位】：山东建筑大学山东省道路与交通工程高校重点实验室;长安大学公路学院;
【基金】：中央高校基本科研业务费专项资金项目,项目编号CHD2011ZD010
【分类号】：TU528

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