长江科学院院报 ›› 2011, Vol. 28 ›› Issue (10): 171-174.

• 水工结构与材料 • 上一篇    下一篇

冻融循环过程中混凝土性能的劣化研究

李家正 a,b ,周世华 a,b ,石妍 a,b   

  1. 长江科学院 a. 材料与结构研究所; b. 水利部水工程安全与病害防治工程技术研究中心, 武汉 430010
  • 出版日期:2011-10-01 发布日期:2012-11-13

Deterioration of Concrete Properties During Freeze-Thaw Cycles

LI Jia-zheng, ZHOU Shi-hua, SHI Yan   

  1. Yangtze River Scientific Research Institute, Wuhan 430010, China
  • Online:2011-10-01 Published:2012-11-13

摘要: 研究了冻融循环过程混凝土性能的劣化特征,探讨了不同测试手段对不同老化特性的敏感性。研究结果表明:混凝土经受冻融循环过程中,混凝土抗折强度、劈拉强度的劣化速度较抗压强度更快;混凝土抗压强度的降低率与质量损失率、相对动弹模之间呈正线性关系;相对动弹模降低到 60% 时,混凝土抗压强度下降到冻融前的19.3%;质量损失达到5%时,混凝土抗压强度下降到冻融前的25.5% ;机械波波速对混凝土冻融破坏的敏感程度界于混凝土强度和超声波波速之间。冻融破坏使水泥水化产物的结构从堆积状密实体逐步变成疏松状态,气泡壁逐步出现了开裂。从孔径分布情况来看,孔径 25~75 nm 之间的孔隙所占的比例呈增大趋势。

关键词: 混凝土 , 冻融循环 , 劣化 , 测试 , 微观结构

Abstract: The deterioration of concrete properties from freezethaw actions are studied and the sensibility of various test methods to different deteriorating characteristics is also explored. It is revealed that the flexural strength and splitting tensile strength of concrete deteriorates more rapidly than compressive strength does, which is positively linearly related to mass loss rate and relative dynamic modulus of elasticity. When relative dynamic modulus of elasticity and mass of concrete are reduced respectively by 40% and 5%, the compressive strength is decreased respectively to 19.3% and 25.5% of the initial value. The sensibility of dynamic mechanical velocity to concrete deterioration during freeze-thaw cycles is between that of concrete strength and ultrasonic velocity. The density of hydration products of cement is decreased due to freeze-thaw actions, giving rise to cracks on the bubble wall and increase of porosities with diameter from 25 nm to 75 nm.

Key words: concrete ,    freeze-thaw cycles  ,   deterioration  ,  test  ,  microscopic structure

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