早期振动对混凝土抗拉性能影响

Effect of Vibrations at Early Concrete Ages on Concrete Tensile Strength

对处于初、终凝前后混凝土材料选取了6个不同时间点作为振动的起振点,分别施加4种不同频率和振幅组合的振动,通过劈裂拉伸强度试验,判断受振动混凝土1、3、28 d抗拉性能变化情况。试验中得到76组劈裂拉伸强度结果,有29个结果是强度降低的。这些强度降低的数据均在10%以内,其中强度降低在7%以内的占了76%。试验结果表明:对处于初、终凝前后混凝土材料施加试验中设计的振动,对1、3、28 d混凝土的劈裂拉伸强度有一定影响。

Four combinations of frequency and amplitude induced vibrations and six start vibrated ages which ensured that the concrete would be exposed to vibration in each of the following age ranges： before initial set,during the setting process,and after final set were designed in the test.The purpose of the splitting tensile strength test is to testify whether the induced vibrations would affect the attainable tensile strength of concrete at cure ages of 1,3 and 28 days.The splitting tensile tests were performed and 76 groups of splitting tensile strength were acquired.There are 29 groups of splitting tensile strength weaker than those of the control group.The 29 data were all reduced less than 10% compared to the control ones,and those reduced less than 7% account for 76% of the weaken data.The test result shows that the designed vibrations induced at the time of before initial set,during the setting process,and after final set in the test have a slight negative effect on the splitting tensile strength of concrete at 1,3 and 28 days.