成型方式对再生混凝土性能影响的试验研究

Experimental research of forming technology effects on propert ies of recycled concrete

通过试验研究了真空脱水、净浆裹石和粗骨料预湿三种成型方式对再生粗骨料混凝土抗压强度和抗氯离子渗透性能的影响。结果表明:(1)随着真空度的增加,再生粗骨料混凝土抗压强度是先增大后减小,最佳真空度为0.06MPa;抗氯离子渗透性能是先增强后减弱,最佳真空度为0.04MPa。(2)净浆裹石对再生粗骨料混凝土抗压强度和抗氯离子渗透性能有一定的影响。用水泥和75%的水拌制的净浆裹石能明显提高再生粗骨料混凝土的抗压强度;用水泥和50%的水拌制的净浆裹石能明显改善再生粗骨料混凝土的抗氯离子渗透性能。(3)再生粗骨料混凝土抗压强度随着预湿再生粗骨料水量的增加而增大;抗氯离子渗透能力随着预湿再生粗骨料水量的增加是先增强后减弱,最佳预湿用水量为配合比水量的3%。

The effects of three forming technologies,vacuum dewatering, interfacing stone enveloped with cement and coarse aggregate pre-wet,on compressive strength and chloride ion penetration of recycled coarse aggregate concrete are researched by experiments.Results show that： 1）The compressive strength of recycled coarse aggregate concrete first increases and then decreases with the increase of the vacuum degree,the best vacuum degree is 0.06 MPa,the chloride ion penetration of recycled coarse aggregate concrete is enhanced firstly and then weakened with the best vacuum degree of 0.04 MPa.2） Interfacing stone enveloped with cement has certain effects on compressive strength and resistance to chloride ion permeability of recycled coarse aggregate concrete.Interfacing stone enveloped with cement result shows that with75% water can significantly increase the compressive strength of recycled coarse aggregate concrete;however, interfacing stone enveloped with cement with 50% water can improve the recycled coarse aggregate concrete resistance to chloride ion penetration significantly.3）With the increase of the amount of coarse aggregate pre-wet water, the compressive strength of recycled coarse aggregate concrete increases and the resistance to chloride ion penetration capacity increases firstly and then decreases, the best amount of coarse aggregate pre-wet water is 3% of mixing ratio water.