摘要
In order to evaluate the carbonation life of newly-built concrete structures,two kinds of nondestructive methods are adopted to test the thickness of the concrete cover and the ultrasonic velocity of two newly-built tunnel structures.Simultaneously a probabilistic method is proposed based on the relationship between the accelerated carbonation rate and the ultrasonic velocity.This proposed method is applied to evaluate the carbonation related lives of two newly-built tunnels and the results indicate that even under nearly the same environment and CO2 combining conditions,there exits a big difference in the probabilistic carbonation lives between the two tunnels;i.e.,the probabilistic lives of Tunnel A and Tunnel B are 94.0% and 82.3% and the corresponding maximum discrepancies are 11.6% and 27.0%,respectively.Thus,it can be concluded that the scattered quality of the concrete cover is attributed to the differences in construction technique,which eventually leads to the diversity in the evaluated probabilistic carbonation lives of the two tunnels.
为了对新建混凝土结构进行碳化耐久性评估,采用无损检测方法对新建隧道混凝土结构保护层密实度和厚度进行了检测,并基于混凝土碳化速度和超声波传播速度之间的线性关系,提出一种用来对新建混凝土结构进行概率碳化寿命评估的方法,并使用该方法对2个隧道混凝土结构进行了概率碳化寿命评估.结果表明:在环境条件及对CO2结合能力基本相同的条件下,2个隧道概率碳化寿命相差较大,其中隧道A的概率碳化寿命均值为94.0%,各标段最大离差为11.6%;隧道B的概率碳化寿命均值为82.3%,各标段最大离差为27.0%.由评估结果分析可知,施工技术水平的不同造成2个新建隧道混凝土结构保护层质量分布出现离散性,从而最终导致2个隧道概率碳化寿命评估结果出现差异.
基金
Key Construction Project of Nanjing Yangtze River Tunnel(No.7612005822)
the National Basic Research Program of China(973Program)(No.2009CB623203).
