EFFECTS OF NAOH AND NACL SOLUTIONS AND TEMPERATURE ON THE BEHAVIOR OFSPECIMENS SUBJECTED TO ACCELERATED AAR TESTS

Accelerated testing of aggregates for alkali-reactivity are performed largely through increasing the alkali level of the test specimens and elevating their storage temperature. Various researchers have used eit her or both of NaOH and NaCl solutions as storage media for specimens at different temperatures, and assessed the reactivity of the aggregat es used in those specimens based on their measured expansion under the respective storage conditions. Authors have not always been able to e xplain their results for the different storage conditions. In this pap er, explanations are offered for the different expansive behaviors of cement-aggregate combinations tested in the presence of 1M NaOH and Na Cl solutions under storage temperatures of 38 degrees C and 80 degrees C. It has been found that the nature of the chemical reactions involv ed in these two solutions and temperatures, and the degree of alkali-r eactivity of the aggregate, significantly influence the expansion of s pecimens of the same composition stored under the different chemical/t emperature regimes. (C) 1998 Elsevier Science Ltd.