| 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. |
| 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 |
| DOI：103969/j.issn1007 9629201605021 |
| 分类号: |
| 基金项目: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） |
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| Influence of Pretreatment Methods on Shrinkage Performance of Recycled Concrete |
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CHEN Xin1, ZHENG Jianlan2, WANG Guojie2
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1.College of Civil Engineering, Fuzhou University, Fuzhou 350116, China;2.Coordinative Innovation Center forEnvironmentally Friendly and Energy Saving HPC, Fuzhou 350108, China
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| Abstract: |
| The factors that affect the autogenous shrinkage and drying shrinkage of recycled concrete were studied, including different recycled coarse aggregate replacement rates(by mass) and pretreatment methods. The experimental results show that the shrinkage strain of recycled concrete is greater than that of normal concrete in the same condition, and the shrinkage strain of recycled concrete increases with the increase of recycled coarse aggregate replacement rate. By using appropriate pretreatment methods, the shrinkage strain of recycled concrete can be greatly reduced. The effects of the same pretreatment method on the autogenous shrinkage and drying shrinkage are different. As for autogenous shrinkage, pre wet method is the best by which the autogenous shrinkage strain of recycled concrete can be about 30.0% lower, and aggregates coated with cement is the next best method. However，the autogenous shrinkage strain of recycled concrete increases by using aggregates coated with cement and adding silica fume. As for drying shrinkage, aggregates coated with cement and adding silica fume is the most effective way by which the drying shrinkage strain of recycled concrete can be reduced by about 15.0%, aggregates coated with cement is the second best method, and pre wet method comes last. Different pretreatment methods can be selected according to the different type of recycled concrete components and their shrinkage characteristics in practical application to make sure the autogenous shrinkage and drying shrinkage of recycled concrete is close to that of normal concrete. |
| Key words: recycled concrete autogenous shrinkage drying shrinkage pre wet method aggregate coated with cement aggregate coated with cement and silica fume |
