Effect of vibration mixing on properties of recycled concrete
In this study,vibration mixing method will be adopted for concrete mixing preparation.Firstly,group experiments are conducted with vibration time and vibration frequency as experimental variables,and it is ob-tained that the strength requirements of C30 concrete design can be met when the vibration time is 90 s and the vi-bration frequency is 40 Hz,and different replacement rates of recycled aggregates are designed under these parame-ters.The effects of vibration mixing on slump,compressive strength and frost resistance of recycled concrete were studied by comparing the data of ordinary mixing and vibration mixing.The results show that the slump of recycled concrete is 9.4%higher than that of ordinary mixed concrete,The compressive strength of recycled concrete meas-ured at 7 d is 18.3%higher than that of ordinary mixed concrete,and When selecting the same replacement rate of recycled coarse aggregate,the compressive strength of recycled concrete at 28 d was measured to be 15.6%higher than that of ordinary mixed concrete.Frost protection exhibited by recycled concrete is improved compared with that of ordinary mixed concrete.It is found that the mechanism of action is that the vibration mixing makes the con-densed cement particles dispersed,so that the hydration is more adequate and the hydration degree increases.In the process of vibration mixing,some residual mortar on the surface of the reclaimed aggregate is broken,which fills the internal pores of the reclaimed aggregate and micro-cracks in the interfacial transition area,making the micro and macro mixing more uniform and the structure more dense.
万方数据
维普
