Journal Published Online: 01 June 1999
Volume 21, Issue 1

Evaluation of the Potential for Internal Sulfate Attack Through Adaptation of ASTM C 342 and the Duggan Test



The potential for distress resulting from internal sulfate attack in mortars was evaluated using a test method adapted from ASTM Test Method (C 342) and the Duggan test. While these test procedures were originally developed to evaluate the potential for cement-aggregate combinations to undergo deleterious alkali-aggregate reactions, the test scheme of temperature and moisture cycling may simulate conditions that are conducive to internal sulfate deterioration.

Length change bars were fabricated from mortars composed of various combinations of a Type I cement: the Type I cement with Class F fly ash; and a Type I/II cement. The aggregate was alkali-silica reactive. The bars were moist cured for seven days after molding at 23°C. Afterward, the bars were subjected to wet-dry, hot-cool cycles over a period of 24 days; one group subjected to a maximum temperature of 55°C and the other to a maximum of 80°C. Two additional groups received the thermal cycling to 55 or 80°C, and a final group was stored continually wet at 23°C. Following the moisture- thermal cycling period, the bars were stored immersed in water for a period of up to one year, and periodically measured for length change. Excessive expansions were noted only with the Type I cement mortars cycled to 80°C, with expansion developing more rapidly in specimens subjected to a drying cycle. Optical microscopic and scanning electron microscopic examinations of specimens indicate that the paste in expansive specimens expanded relative to aggregate particles.

Author Information

Lane, DS
Virginia Transportation Research Council, Charlottesville, VA
Ozyildirim, HC
Virginia Transportation Research Council, Charlottesville, VA
Pages: 16
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Stock #: CCA10508J
ISSN: 0149-6123
DOI: 10.1520/CCA10508J