Study On Vibration Technology Of Zero Slump Concrete

Due to the special requirements of the existing synovial paving technology for concrete,hard drying concrete can't applicable for that.Combined with the research achievements at home and abroad,we put forward to the concept of zero slump concrete.Zero slump concrete has good integrity.Zero slump concrete with high frequency vibration can do with rapid liquefaction of slurry and discharge gas inside.In this way it can ensure the smoothness of pavement.But the poor workability is an indelible short board.Based on this,this paper focuses on the performance of zero slump concrete from the point of view of concrete workability and vibrating process.The concrete contents are as follows:(1)The basic performance of zero slump concrete is analyzed synthetically from the point of view of concrete workability,strength and durability.A series of tests are carried out by designing different water-cement ratio and sand rate value.We got that when the water cement ratio is 0.44 and sand ratio is 40%,the concrete has good performance.(2)The concept of vibration expansion degree and the test method are put forward according to the principle of liquefaction of concrete and slump expansion index.Taking the differences test materials into account,the final determination of zero slump concrete vibration expansion range is 33-38 cm.Based on the large data test,the cohesion of concrete is evaluated from the difference between the actual slurry vibration expansion degree and the expansion of aggregate density,and the empirical evaluation index is given.The bubbles in the concrete were simulated by using a small ball with a diameter of 3cm.The tests that small ball simulates bubbles were carried out for the concrete with different water-cement ratio and different sand ratio.The results showed that the small balls in the concrete with water-cement ratio of 0.44 and sand ratio of 40% will have shortest time to float to the concrete surface.(3)The acceleration of the concrete is measured by the acceleration acquisition system.The acceleration value is gradually reduced with the increase of the sensor distance under the high frequency vibrating condition.And each channel from acceleration is consistent with the change of time.As time increases,the acceleratio increases first and then decreases finally stable,and ultimately determine the frequency vibrator effective vibration time is 60 s,the vibration range is 20 cm.(4)The influence of the vibratory time on the compactness of the concrete at different vibration frequencies of the vibrating table is studied by measuring the flexural strength of the concrete under the measured age.The results show that the vibration frequency is 50 Hz,110hz and 140 hz,the optimal vibration time were 90 s,70s and 60 s.if more than the best vibration time,concrete density change is small,but the probability of segregation will increase.And the relationship between vibration frequency and vibration time is not obvious.