Materials Reports  2019, Vol. 33 Issue (z1): 239-243 |
| INORGANIC MATERIALS AND CERAMIC MATRIX COMPOSITES |
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| Effect of Air Entraining Agent on Sulfate Crystallization Distress on Sulphoaluminate Cement Concrete |
| HU Wenlong, LIU Zanqun, PEI Min
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| School of Civil Engineering, Central South University, Changsha 410075 |
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Abstract Air-entraining agent is a chemical admixture used to improve frost resistance of concrete in concrete freeze-thaw damage. The mechanism of action is to introduce a large number of bubbles in the concrete mixing process to change the pore structure of the concrete and then reduce the icing pressure in the freeze-thaw damage. The physical crystallization damage of concrete is similar to the freeze-thaw damage in the failure mechanism. It is the change of the shape of the liquid in the pores of the concrete after the temperature or humidity changes. Therefore, in theory, the addition of air entraining agent should also alleviate the physical crystallization damage of concrete.So,in the environment of constant temperature and humidity (temperature (18±1) ℃, relative humidity (50±5)%), sulphoaluminate cement concrete specimens with 0, 0.5 air entraining agent were partially immersed in 10% sodium sulphate solution .The deformation morphology of concrete moisture evaporation zone, strength and mass loss rate and pore diameter change were analyzed after immersion for 35 d, 70 d and 130 d,in order to explore the effect of air entraining agent on the physical crystallization damage of concrete.The results show that the incorporation of air entraining agent will change the pore size distribution and pore shape of concrete. The proper amount of air entraining agent can improve the sulfate resistance of sulphoaluminate cement concrete, however, when the air entraining agent is excessively mixed, the concrete specimens became softer, which in turn leads to more severe strength loss.
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Published: 05 July 2019
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| About author:: Wenlong Hu is a graduate student at the School of Civil Engineering, Central South University, he is mainly engaged in the field of sulfate attack in concrete.Zanqun Liu received his Ph.D. degree in in road and railway engineering from Central South University in 2010. He is currently a professor in Central South University.His research interests are key engineering materials for high-speed rail, cement emulsified mortar, self-compacting concrete and concrete durability.He is a reviewer of Construction and Building Materials and Journal of the Chinese Ceramic Society He has hosted and participated in several Natural Science Foundations of China in recent years. In addition, he has published more than 20 journal papers, won 3 provincial and ministerial research awards. |
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