Deterioration Mechanism of Sulfate Attack on Concrete under Freeze-thaw Cycles
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2013年第6期
论文作者：NIU Ditao JIANG Lei FEI Qiannan
文章页码：1172 - 1176
摘 要：The experiments of concrete attacked by sulfate solution under freeze-thaw cycles were investigated. The sulfate solution includes two types of 5% Na 2 SO 4 and 5% MgSO 4. Through the experiment, microstructural analyses such as SEM, XRD and TGA measurements were performed on the selected samples after freeze-thaw cycles. The corrosion products of the concrete were distinguished and quantitatively compared by the thermal analysis. Besides, the damage mechanism considering the dynamic modulus of elastically of concrete under the coupling effect was also investigated. The experimental results show that, under the action of freeze-thaw cycles and sulfate attack, the main attack products in concrete are ettringite and gypsum. The corrosion products exposed to MgSO 4 solution are more than those to Na 2 SO 4 solution. Furthermore, the content of gypsum in concrete is less than that of ettringite in test, and some of gypsum can be observed only after a certain corrosion extent. It is also shown that MgSO 4 solution has a promoting effect to the damage of concrete under freeze-thaw cycles. Whereas for Na 2 SO 4 solution, the damage of concrete has restrained before 300 freeze-thaw cycles, but the sulfate attack accelerates the deterioration process in its further test period.
NIU Ditao，JIANG Lei，FEI Qiannan
School of Civil Engineering,Xi’an University of Architecture and Technology
摘 要：The experiments of concrete attacked by sulfate solution under freeze-thaw cycles were investigated. The sulfate solution includes two types of 5% Na 2 SO 4 and 5% MgSO 4. Through the experiment, microstructural analyses such as SEM, XRD and TGA measurements were performed on the selected samples after freeze-thaw cycles. The corrosion products of the concrete were distinguished and quantitatively compared by the thermal analysis. Besides, the damage mechanism considering the dynamic modulus of elastically of concrete under the coupling effect was also investigated. The experimental results show that, under the action of freeze-thaw cycles and sulfate attack, the main attack products in concrete are ettringite and gypsum. The corrosion products exposed to MgSO 4 solution are more than those to Na 2 SO 4 solution. Furthermore, the content of gypsum in concrete is less than that of ettringite in test, and some of gypsum can be observed only after a certain corrosion extent. It is also shown that MgSO 4 solution has a promoting effect to the damage of concrete under freeze-thaw cycles. Whereas for Na 2 SO 4 solution, the damage of concrete has restrained before 300 freeze-thaw cycles, but the sulfate attack accelerates the deterioration process in its further test period.
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