Title: Petrographic Evaluation of Aggregates Affected by Tectonic Deformation in Development of Alkali-Silica Reaction

Author(s): Adelson Prado, Yane Coutinho, Fernanda Ferreira, Gorki Mariano, and Arnaldo Carneiro

Publication: Materials Journal

Volume: 119

Issue: 4

Appears on pages(s): 39-48

Keywords: aggregate; alkali-aggregate reaction; alkali-silica reaction; fault zones; petrography

DOI: 10.14359/51734684

Date: 7/1/2022

Abstract:
The deterioration of concrete due to alkali-silica reaction (ASR) is a worldwide problem. Rocks close to shear and/or fault zones generally favor the occurrence of this reaction when used as aggregates in concrete. This study evaluated six coarse aggregates from quarries at different distances from shear and fault zones in the eastern part of the state of Pernambuco, Brazil, to verify the influence of tectonic deformation in the aggregate reactivity. Petrographic analyses and accelerated mortar bar tests were performed. The presence of microcrystalline quartz from dynamic recrystallization in samples collected closer to transcurrent shear zones provided higher reactivity. Therefore, a strong correlation between expansion/microcrystalline quartz content and distance from transcurrent shear zones was obtained. Thus, the geological mapping and characterization may provide an initial and fast indication of the reactive potential of aggregates, being a guidance for the choice of the extraction location or an initial indication of the need to use mitigation measures.