RISK ASSESSMENT OF A POTENTIAL EXTERNAL AND INTERNAL SULFATE ATTACK IN POZZOLANIC CEMENTITIOUS MATRICES

This work evaluated the behavior of cementitious composites against internal and external attack by sulfates (ISA and ESA, respectively) over time, as well as the mitigating potential of Brazilian cements considered pozzolanic. Three pozzolanic cements called sulfate resistant according to Brazilian standards were evaluated, coming from three regions of Brazil, in addition to a reference cement, with high initial resistance. Based on evaluations by Brazilian (ABNT) and American (ASTM) standardization, it was found that the use of pozzolanic additions to cement brings mainly mechanical and durability improvements in relation to external sulfate attack, however, depending on the standardization adopted, it is not possible to say whether it contributed to the mitigation of this attack. In relation to ISA assessments, no cement proved to be effective. Therefore, among the four cements tested, considering the criteria adopted in the study, no cement could be considered to mitigate expansions caused by both sulfate attacks, external - (ESA) and internal - (ISA).