A comparison of RTA T363 and ASTM C1260 accelerated mortar bar test methods for detecting reactive aggregates

Abstract

Nowadays, bridge structures are designed for 100 years of service life, and care must be taken to avoid materials that would cause premature deterioration problems in the structures. This requires careful attention to structural design, selection of sound materials and manufacture of components, which would remain durable under the given environmental conditions (exposure and loading). One of the important concrete deterioration problems is the alkali–aggregate reaction (AAR), which can cause cracking and diminished strength properties in concrete, and the best method of avoiding it is to select nonreactive aggregates for the concrete or those that could safely be combined with mineral additives to suppress their reactivity. The purpose of this paper is to compare the expansion results obtained by the two test methods using a number of aggregates with known field performance and to assess the validity of their expansion limits in predicting the field performance of these aggregates. The paper also covers the comparison of the two test methods for the assessment of the effectiveness of fly ash in suppressing AAR expansion.