振动拌和对再生混凝土性能的影响  

Effect of vibration mixing on properties of recycled concrete

作　　者：宋维昌 Song Weichang(Qinghai Guoluo Highway Engineering Construction Co.,Ltd.,Xining,810000,China)

机构地区：[1]青海省果洛公路工程建设有限公司,西宁810000

出　　处：《青海交通科技》2024年第1期140-147,共8页Qinghai Transportation Science and Technology

基　　金：青海省重点研发项目(2023—SF—123)。

摘　　要：采用振动拌和方法进行混凝土的搅拌制备,以振动时间、振动频率为试验变量进行分组试验,得到在振动时间为90 s、振动频率40 Hz时满足C30混凝土设计的强度要求。在此参数下设计不同再生骨料取代率,分别对普通拌和与振动拌和所得的再生混凝土进行塌落度、抗压强度、抗冻性能的数据测定和研究。结果表明:振动拌和所得的再生混凝土塌落度提升了9.4%,在再生骨料取代率相同的情况下,再生混凝土的7 d抗压强度有明显的提升,高达18.3%,而28 d抗压强度对比提升了15.6%。同时,其抗冻性能相对于普通混凝土也有非常明显的提升,研究得到其作用机理是振动搅拌使凝聚的水泥团粒被振散,使水化更充分,水化程度增加。振动拌和过程中再生骨料表面的部分残余砂浆破碎,填补了再生骨料的内部孔隙及其界面过渡区的微裂缝,使微观和宏观混合更加均匀,结构更加密实。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 obtained that the strength requirements of C30 concrete design can be met when the vibration time is 90 s and the vibration frequency is 40 Hz,and different replacement rates of recycled aggregates are designed under these parameters.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 measured 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 condensed 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.

关 键 词：振动拌和 塌落度 抗压强度 抗冻性能 

分 类 号：TU528[建筑科学—建筑技术科学]