Title: Assessing Performance of Sulfate-Resistant Portland Cements
Author(s): Diana Gagatek and R. Douglas Hooton
Publication: Materials Journal
Appears on pages(s): 227-233
Keywords: ASTM test methods; Bogue calculations; ettringite; magnesium oxide (MgO); sulfate attack; sulfate-resistant portland cement, X-ray diffraction
ASTM C452 accelerated sulfate resistance tests were performed using 10 ASTM Type V portland cements mixed with sufficient gypsum to obtain 7% sulfur trioxide content by mass of cement. The purpose was to compare the test results (optional test in ASTM C150 for Type V cements) to the tricalcium aluminate contents calculated by the Bogue equations. Tricalcium aluminate contents were also measured using X-ray diffraction with Rietveld refinement. It was found that the Bogue equations alone were not sufficient for identifying sulfate-resistant portland cement that exhibited good performance in ASTM C452. In addition, ASTM C452 expansions were compared with ASTM C1012 mortar bar expansions in sodium sulfate solution and ASTM C1038 mortar bar expansions in water. It was found that cement with a high MgO content appeared to increase 12-month C1012 expansions, likely due to formation of brucite, thus interfering with interpretation of test results.