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Matches in UGent Biblio for { ?s ?p Sulfate attack comprises a series of chemical reactions between sulfate ions and the components of hardened concrete. As these reactions may lead to cracking, spalling or strength loss of concrete structures, appropriate test methods are needed to determine the resistance of cncrete under sulfate exposure. Accelerated test methods are most suitable since sulfate attack is a long term process. Current ASTM C1012 test method accelerates the attack mechanism by using a solution with a high sulfate concentration in which the samples are immersed. The SVA procedure uses smaller specimens to obtain results earlier. In the Wittekindt method not only smaller specimens are used but also the W/C-ratio is increased. However these tests still last for several months. Test methods such as ASTM C452 and the Chatelier-Anstett test use a mixture of cement and gypsum, simulating internal sulfate attack. Results are already obtained after two weeks, but the attack mechanism is no longer representing field conditions in a realistic way. Another problem relates to the way to quantify the degree of degradation. SVA, Wittekindt, Duggan, ASTM C1012 and C452 use expansion measurements. Mehta and Gjorv proposed to use decrease in compressive strength and in the rapid electrochemical test current is measured to determine degradation. Depending on the selected degradation measure, different conclusions can be drawn regarding the performance of concrete under sulfate attack. In this paper an overview of the existing test method is given and a critical discussion is performed.. }

• aggregation abstract "Sulfate attack comprises a series of chemical reactions between sulfate ions and the components of hardened concrete. As these reactions may lead to cracking, spalling or strength loss of concrete structures, appropriate test methods are needed to determine the resistance of cncrete under sulfate exposure. Accelerated test methods are most suitable since sulfate attack is a long term process. Current ASTM C1012 test method accelerates the attack mechanism by using a solution with a high sulfate concentration in which the samples are immersed. The SVA procedure uses smaller specimens to obtain results earlier. In the Wittekindt method not only smaller specimens are used but also the W/C-ratio is increased. However these tests still last for several months. Test methods such as ASTM C452 and the Chatelier-Anstett test use a mixture of cement and gypsum, simulating internal sulfate attack. Results are already obtained after two weeks, but the attack mechanism is no longer representing field conditions in a realistic way. Another problem relates to the way to quantify the degree of degradation. SVA, Wittekindt, Duggan, ASTM C1012 and C452 use expansion measurements. Mehta and Gjorv proposed to use decrease in compressive strength and in the rapid electrochemical test current is measured to determine degradation. Depending on the selected degradation measure, different conclusions can be drawn regarding the performance of concrete under sulfate attack. In this paper an overview of the existing test method is given and a critical discussion is performed.".