早期振动引起混凝土离析变化规律及对后期强度影响
Effect of Vibrations at Early Concrete Ages on Concrete Segregation and Strength
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摘要: 为了确定早期振动对混凝土离析性能的影响,采用0.05、0.08、0.16、0.19、0.32 g五种振动加速度,对坍落度为70、120、160 mm的新拌混凝土进行振动试验;分析了振动时间、振动能量和坍落度对混凝土最大离析系数的影响,以及不同离析程度混凝土后期抗压强度的变化情况.结果表明:受振动混凝土产生的离析随振动时间的增加而趋于稳定;同一坍落度混凝土在振动能量达到一定程度后离析趋于稳定;较大振动能量时,混凝土离析变化受坍落度影响较大;较小能量振动对受振混凝土抗压强度有增强作用;在振动能量较大、混凝土坍落度较大时,受振混凝土的抗压强度有下降的趋势.Abstract: In order to testify whether the traffic vibrations at early concrete ages would affect the concrete segregation and compress strength,a series of vibration tests with five different vibration acceleration values were conducted to the fresh concrete with slumps of 70 mm,120 mm and 160 mm respectively.According to the test results,the segregation of the vibrated concrete tends to be stable with the vibration time lasting. The slump of the concrete influences the concrete segregation only when vibration energy is high. Based on the relationship between the compress strength of the vibrated concrete and their segregation factor,low level vibration energy increases the concrete compress strength and high level vibration energy and high slump decreases the compressive strength of concrete.