Influence of Shrinkage Cracks on Chloride Penetration and Crabonation of Concrete
JIN Zu-quan,HOU Bao-rong,ZHAO Tie-jun and ZHANG Peng
DOI:10.11835/j.issn.1674-4764.2011.01.003
Received June 16, 2010,Revised , Accepted , Available online July 01, 2015
Volume ,2011,Pages 7-11
- Abstract
The influence of shrinkage crack on chloride ion penetration and carbonation of concrete is investigated. The concrete samples with shrinkage crack of 0.07 mm，0.1 mm，0.2 mm，0.4 mm and 0.62 mm are prepared, and both an accelerated carbonation test and Qingdao sea water corrosion test are conducted on sound concrete and cracked concretes. The depths of carbonation, the content of free chloride and total chloride in crack zone and perimeter zone of concrete are analyzed. The enperimental result shows that both free chloride and total chloride content in cracked concrete increase with the rise of the shrinkage crack width, and they are related in quadratic function. The chloride penetration velocity in crack zone is higher than that in perimeter zone of concrete. However, the increased specific surface in shrinkage crack tip improves chloride binding capacity and decreases the free chloride content in this zone. When the shrinkage crack is less than 0.07mm, the carbonation depth in crack zone is same as that of sound concrete. The chloride diffusion coefficient and the carbonation depth of cracked concrete increase limited as the shrinkage crack is less than 0.1mm, and then increase significantly with the increasing of shrinkage cracked width. Moreover, the carbonation depth in crack zone is increased by 3mm in comparison with that in perimeter zone of cracked concrete.