预处理方法对再生混凝土收缩性能的影响

发布时间：2018-02-25 23:09

本文关键词： 再生混凝土自收缩干燥收缩预湿法净浆裹石法掺硅灰的净浆裹石法　出处：《建筑材料学报》2016年05期 　论文类型：期刊论文

【摘要】：以再生粗骨料的预处理方法及其取代率(质量分数)为变化因素,研究了再生混凝土自收缩和干燥收缩应变的变化规律.结果表明:再生粗骨料未预处理的再生混凝土,其自收缩和干燥收缩应变均大于相同条件下的普通混凝土,且随再生粗骨料取代率的提高而增大.采用合适的预处理方法,可明显减小再生混凝土的收缩应变,但自收缩和干燥收缩应变的改善效果各不相同.对于再生混凝土自收缩,预湿法的改善效果最佳,可减小自收缩应变约30.0%,净浆裹石法居中,而掺硅灰的净浆裹石法会使自收缩应变增加;对于再生混凝土干燥收缩,掺硅灰的净浆裹石法的改善效果最佳,可减小干燥收缩应变约15.0%,净浆裹石法居中,而预湿法次之.在实际应用中,可视不同体型的再生混凝土构件,根据其收缩特性选择不同的预处理方法,使其自收缩与干燥收缩应变接近普通混凝土.
[Abstract]:With the pretreatment method of recycled coarse aggregate and its replacement ratio (mass fraction) as the variable factors, the variation of the strain of autogenous shrinkage and dry shrinkage of recycled concrete is studied. The results show that the recycled concrete without pretreatment of recycled coarse aggregate is not pretreated with recycled aggregate. The strain of autogenous shrinkage and dry shrinkage is higher than that of ordinary concrete under the same conditions, and increases with the increase of the replacement rate of recycled coarse aggregate. The shrinkage strain of recycled concrete can be obviously reduced by using proper pretreatment method. But the effect of autogenous shrinkage and dry shrinkage strain are different. For recycled concrete, the effect of pre-wet method is the best, which can reduce the autogenous shrinkage strain of about 30.0%, and the method of paste wrapped in stone is the middle. The autogenous strain of recycled concrete can be increased by the method of adding silica fume, and the method of adding silica fume can improve the drying shrinkage of recycled concrete, which can reduce the strain of drying shrinkage about 15.0, and the method of clean slurry wrapping stone is the middle one. In practical application, the recycled concrete members with different shapes can be treated with different pretreatment methods according to their shrinkage characteristics, so that the strain of autogenous shrinkage and dry shrinkage is close to that of ordinary concrete.
【作者单位】：福州大学土木工程学院;福建省环保节能型高性能混凝土协同创新中心;福建江夏学院工程学院;
【基金】：国家自然科学基金资助项目(51278124,51578153) 福建省发改委重点项目(TM2012-14) 福建省自然科学基金资助项目(2014J01172)
【分类号】：TU528

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