Effect of Carbonation on Concrete Performance in Sewage Environment

作者：Kong, Lijuan; Han, Mengdi; Wu, Zhigang

来源：Journal of the Chinese Ceramic Society, 2018, 46(8): 1117-1125.

DOI：10.14062/j.issn.0454-5648.2018.08.11

• Carbonated concretes
• Comprehensive analysis
• Concrete performance
• Deterioration rates
• Hydration products
• Microbial metabolism
• Mineral composition
• Sewage environments

The appearance, mass, strength, surface pH value, morphology and mineral compositions of non-carbonated and 60-day carbonated concretes in intensified sewage were investigated. The results show that although the compressive strength of carbonated concrete is significantly greater than that of non-carbonated concrete, it has a faster deterioration rate, which is approximately two times greater than that of non-carbonated concrete. After 90-day sewage corrosion, the strength of carbonated concrete is reduced by 44%, and the mass loss is 10%, as well as the surface pH value decreases to 4.21, however, the mass of biofilm attached is obviously more than that of non-carbonated concrete. The results of the decreased pH value of sewage and the microscopic test show that the corrosion of sewage on concrete is mainly caused by some acidic substances produced by microbial metabolism. The structure of cement paste becomes loose and porous, and the content of Ca(OH)2decreases greatly, especially for the carbonated specimen, of which is only 0.20% after 1-month corrosion. Furthermore, after 3-month corrosion, no apparent diffraction peaks of hydration products appear in both specimens. The comprehensive analysis indicates that despite CaCO3can make the concrete denser, either the microcracks produced by carbonation shrinkage or the weak alkali surface caused by carbonation could accelerate the biologic acid corrosion of concrete.

• 出版日期2018
• 单位石家庄铁道大学