Degree Granting Department
gypsum, expansion, compressive strength, sulfur trioxide, sulfate attack
The objective of this investigation was to assess the influence of the SOâ content on the durability and strength of portland cement. Four portland cements were used in this study. The cements had a variable tricalcium silicate, tricalcium aluminate, and alkali contents, as well as differences in the amount and form of calcium sulfates. The SOâ content of the cements was increased by replacing part of the cement by gypsum according to ASTM C 452-95. Mortar bars and cubes were prepared for the as-received as well as for the cements with an SOâ content of 3.0% and 3.6%. The durability of the as-received and doped cements was determined by measuring the length change of the mortar bars that were exposed to sodium sulfate environment. The compressive strength of the mortar cubes prepared for the same mixes was measured at different ages for sets of cubes cured both in sodium sulfate solution and in saturated lime solution.
It was concluded at the end of this study that there is an optimum SOâ content for the lowest expansion that is different from that determined for the highest compressive strength. Optimum values also differed from one cement to another and from one age to another for the same cement. The results also indicate the dependence of SOâ content on tricalcium aluminate and alkali content of cements. In addition, for all cements examined in this study with alkali content of less than 0.60%, increasing the SOâ content above 3.0% had negative effects on durability assessed by strength or expansion measurements. For the cement with highest alkali and tricalcium aluminate content, increasing the SOâ content from 3.0% to 3.6% delayed the onset of strength drop; however, at 360 days the strength drop experienced by both doping levels was the same.
Scholar Commons Citation
Hanhan, Amin A., "Influence of the SOâ content of cement on the durability and strength of concrete exposed to sodium sulfate environment" (2004). Graduate Theses and Dissertations.