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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。
In order to study the degradation mechanism of cement concrete under vehicle load, freeze-thaw cycle and wet-dry cycle, and analyze the influence of cracks on the performance deterioration of concrete, the accelerated loading, wet-dry cycle and Freeze-thaw cycle test, get the relative dynamic modulus of the specimen, mass loss and strength changes, the performance degradation of concrete. The test results show that the performance of cement concrete is not obvious under the repeated load of vehicles, but the compressive strength of concrete decreases obviously due to the existence of cracks. The performance of concrete deteriorates obviously under the condition of wet-dry cycle. The compressive strength of concrete under 56 cycles 20%, the presence of cracks has little effect on the performance deterioration of concrete; the performance of concrete under the freeze-thaw cycle is particularly prominent. The flexural strength of concrete without cracks and cracks with 150 freeze-thaw cycles decreases by 48.3% and 52.3% %. It can be seen that freeze-thaw cycles and wet-dry cycles are the main reasons for the deterioration of cement concrete performance. The presence of cracks does not accelerate the deterioration of concrete performance, but the presence of cracks makes it easier for water to enter the pavement structure, Concrete undergoes wet-dry cycles and freeze-thaw cycles, and the fatigue of vehicle loads accelerates deterioration of pavement concrete.