| 摘要: |
| 在高水胶比混凝土中掺加不同类型减缩剂（内养护剂(SAP)、膨胀剂及有机减缩剂），然后研究不同类型减缩剂对混凝土抗压强度、化学收缩、自收缩、干燥收缩、塑性开裂的影响，对比分析不同类型减缩剂在不同混凝土养护条件下的减缩效果.结果表明：SAP、膨胀剂、有机减缩剂对混凝土3d抗压强度均有不同程度的负面影响，其中有机减缩剂负面影响最大，但SAP可促进混凝土28d抗压强度增长；SAP对混凝土化学收缩、自收缩、干燥收缩及塑性开裂均具有较好改善效果，这缘自于SAP对混凝土内部相对湿度的调控作用；膨胀剂对混凝土养护条件要求苛刻，在密封条件下膨胀剂具有较好的补偿自收缩作用，但在干燥养护条件下膨胀剂补偿干燥收缩的效果并不理想；有机减缩剂对密封条件下混凝土自收缩的补偿效果不如SAP及膨胀剂，但在干燥条件下其具有良好的补偿混凝土干燥收缩的效果，这是因其能降低混凝土溶液表面张力和内部水分蒸发速率的缘故. |
| 关键词: 高水胶比 内养护 膨胀剂 减缩剂 收缩 |
| DOI：103969/j.issn1007 9629201601009 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51172173） |
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| Comparative Analysis of Reduction Effects of Different Shrinkage Reducing Agents in Concrete |
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YANG Jin1, WANG Fazhou1, HUANG Jin2, SHANG Dechen1
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1.State Key Laboratory of Silicate Materials for Architecture, Wuhan University of Technology, Wuhan 430070, China;2.Technical Center, Huaxin RMXAGG Business Department, Wuhan 430080, China
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| Abstract: |
| Three different types of shrinkage reducing agents(internal curing agent(SAP), expanding agent and organic shrinkage reducing agent) were introduced to the concrete with high water binder ratio,and then the effects of these shrinkage reducing agents on the compressive strength, chemical shrinkage, autogenous shrinkage, drying shrinkage and plastic cracking of concrete were studied. Reduction effects of different shrinkage reducing agents under different curing conditions of concrete were compared. Results indicate that SAP, expanding agent and organic shrinkage reducing agent all have negative effects on the 3d compressive strengths of concrete, of which the organic shrinkage reducing agent affects the most, and SAP promotes the 28d compressive strength of concrete. The SAP has better improvement effect on chemical shrinkage, autogenous shrinkage, dry shrinkage and plastic cracking because of its synergistic effect on the internal relative humidity of concrete. Expanding agent has harsh demand for the curing conditions of concrete with high water binder ratio which means that expanding agent compensates shrinkage well in seal curing conditions and defectively in dry curing conditions. As for autogenous shrinkage of concrete, organic shrinkage reducing agent performs not as well as SAP and expanding agent in seal curing condition because of the lack of “self expanding effect”. However, for drying shrinkage of concrete, the organic shrinkage reducing agent performs well in dry curing conditions, because it reduces the surface tension of pore solution in concrete and slows down the evaporation rate of internal water at the same time. |
| Key words: high water binder ratio internal curing expanding agent shrinkage reducing agent shrinkage |
