Study On Test Method For Cement Concrete To Sulphate Attack

The sulfate attack is the most extensive and common form in the concrete chemical corrosion, and it has been an important part of structure durability research. Although so far there are many sulfate attack test methods that had been proposed, each method has some limitations and not any method can reveal concrete sulfate attack mechanism quickly and truthfully, especially is used to forecast various capability of concrete that is in the sulfate attack environment for long term. Therefore, it is very important to investigate test method of resistance to sulfate attack systematically.Now the national standard test methods are mainly used to evaluate capability of resistance to sulfate attack of cement gel material. Resistance to sulfate attack of concrete relates to not only cement gel material but also its compactness. Thus, different researchers in the resistance to sulfate attack study, according to different research purposes, adopt different test methods.In this paper, object of study is concrete containing fly ash and preservatives. Discuss test methods and evaluation parameter of resistance to sulfate attack of cement mortar and concrete which include test methods of national standards and some of the scientific research institutes. Test parameters of the various methods are modified in order to obtain actually more feasible experimental parameter and correlative evaluation parameter. At the same time, microscopic mechanism of all methods is analysed by using the scanning electron microscope technology from microcosmic point of view.GB\T 2420—81 and GB\T 749—2001 are about resistance to sulfate attack of cement mortar. Main study contents of cement mortar are resistance to sulfate attack of fly ash and preservatives, size changes of sand particle, pressure changes of manufacture and evaluation parameter about corrosion resistance coefficient and bulge ratio.Resistance to sulfate attack test methods of concrete adopt drying-wetting cycles and long-term immersion. Main study contents of concrete are sensitivity of cube and prism, influence of solution temperature and concentration on resistance to sulfate attack, resistance to sulfate attack capability of different intensity levels of concrete and comparing analysis between drying-wetting cycles and long-term immersion.The result shows that resistance to sulfate attack capability of the same proportion of cement mortar and concrete specimens is accordant, the results of drying-wetting cycles and long-term immersion are accordant, the ideal test results can be gained by changing the relevant parameters of the methods.