混凝土硬化过程中的应力-应变发展和基于内部湿度的开裂风险预估

发布时间：2018-01-03 05:04

本文关键词：混凝土硬化过程中的应力-应变发展和基于内部湿度的开裂风险预估　出处：《工程力学》2014年03期 　论文类型：期刊论文

【摘要】：建立了一种对水泥混凝土开裂风险进行评估的新方法。模型基于硬化过程中混凝土的应变-约束应力发展,研究了开裂时间与收缩变形率和混凝土内部湿度降低率的关系。研究结果表明:混凝土开裂风险与收缩变形速率有关,开裂时间与开裂时的临界收缩率存在唯一对应关系。该研究根据混凝土湿度与变形的关系,提出了一个基于混凝土内部湿度降低速率的混凝土早期开裂预估方法。该方法避免了工程实际中为确定混凝土开裂风险而需要进行的变形测量及复杂的需要考虑徐变、应力松弛、强度和模量的发展等因素但又未必准确的应力计算过程,简化了混凝土硬化过程中的开裂风险预测。
[Abstract]:A new method for evaluating the cracking risk of cement concrete is established. The model is based on the development of strain-confined stress in concrete during hardening. The relationship between cracking time and shrinkage deformation rate and the reduction rate of internal humidity of concrete is studied. The results show that the cracking risk of concrete is related to the shrinkage deformation rate. There is a unique relationship between the cracking time and the critical shrinkage rate during cracking. This study is based on the relationship between moisture and deformation of concrete. A concrete early cracking prediction method based on the decreasing rate of internal humidity of concrete is proposed, which avoids the deformation measurement and complex consideration in engineering practice to determine the risk of concrete cracking. Creep. The stress relaxation, the development of strength and modulus and other factors, but not necessarily accurate stress calculation process, simplifies the crack risk prediction in the hardening process of concrete.
【作者单位】：清华大学土木工程系;交通运输部公路科学研究院;
【基金】：国家自然科学基金项目(51108246) 教育部博士点新教师基金项目(20110002120010) 交通运输部西部交通科技项目(2011318223710)
【分类号】：TU528
【正文快照】： 水泥混凝土由于硬化过程中温度、湿度变化,会产生相应的体积变化,其引起的收缩变形在受到内部和外部约束的情况下,易在混凝土内产生拉应力而导致裂缝和耐久性问题。如何对混凝土,特别是早龄期混凝土的开裂风险进行评估,对于预先采取措施(如优化设计、材料的选取、施工工况的选

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