Title: Development Of A Performance Measure For Durability Of Concrete Bridges

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Publication: CIA

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Date: 2/13/2011

Abstract:
Major durability problems for concrete structures is the alkali-aggregate reaction (AAR) which can lead to premature cracking and deterioration of the structure. To ensure satisfactory performance of the structure, the aggregate component needs to be tested prior to construction and managed according to its reactivity. For reactive aggregates that have already been used and caused cracking in the structure, it is important to estimate their effect on the strength properties of the structural elements. Some 18 commercial aggregates that could be used in concrete for VicRoads bridge constructions, were selected to investigate their influence on the durability and strength properties of the concrete. A number of bridges in which some of the aggregates had been used were also investigated to provide data on the field performance of the aggregate. The work reported here has shown that the accelerated mortar bar test (AMBT), adopted by VicRoads as test method RC376.03 and by RTA, NSW as RTA test method T363, is effective in detecting reactive aggregates and its results correlate well with the performance of the aggregates in the concrete prism test and in the bridges examined. The compressive strength of concrete was found to be less sensitive to ARR expansion than flexural (or tensile) strength. Based on the results obtained it would be expected that at expansions exceeding 0.12%, the flexural (or tensile) strength of concrete elements could be reduced by as much as 40-50%.