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Title |
Sulfate Attack Resistance and Microstructural Observations of Cement Matrix Exposed to a Low Temperature Condition
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Keywords |
황산염침식 ; 시험용액 온도 ; 미세구조적 조사 ; 쏘마싸이트 sulfate attack ; solution temperature ; microstructural observations ; thaumasite |
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Abstract |
This paper reports an experimental study on the damage mechanism and resistance of Type I portland cement mortar and paste samples exposed to 5% sodium sulfate solution with different solution temperatures; namely, 4oC, 10oC and 20oC. The resistance of mortar samples was evaluated using expansion, compressive strength and flexural strength measurements. Some microstructural observations such as x-ray diffraction, differential scanning calorimetry and scanning electron microscopy were also introduced to elucidate reactants formed by sulfate attack, especially in a low temperature condition. From the results, it was found that the degree of damage in the mortar samples was significantly associated with the temperature of sulfate solution. Low temperature of the sulfate solution led to the formation of thaumasite in mortar and paste samples, and subsequently a poor resistance to sulfate attack. Thus, it is noted that when concrete structures are exposed to sulfate media in the condition of a cold region or whether, special care should be taken.
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