Siliceous and dolomitic-bearing aggregates reaction in Tetramethylammonium hydroxide

Due to argillaceous dolomitic limestones usually contain more or less quartz or micro-crystalline quartz, based on existence of alkali-silica gels in concretes with dolomitic aggregates, lead to alkali-carbonation reaction (ACR) coexists with alkali-silica reaction (ASR) in concrete. This paper focuses on distinguish ASR are affected by the presence of Tetramethylammonium hydroxide (TMAH) solution to offer a better understanding of the effect of ADR on the mitigation process of alkali-carbonation reaction (ACR). In this work, X-ray diffraction (XRD), laser scanning confocal microscopy (LSCM) and scanning electron micro-scopy (SEM) were carried out analyses of products. The results presented strongly support that the TMAH has no react on reactive silica, and thus stop further attack on the reactive silica by hydroxyl lions. According to the results of the tests, the presence of TMAH is sufficient to promote the ADR in samples with dolomitic aggregates, formation products of brucite and calcite. Therefore, it was concluded that evi-dence to support the theory of TMAH can distinguish ASR and ADR when dolomitic aggregate bearing quartz. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study found that Tetramethylammonium hydroxide (TMAH) has a certain impact on the alkali-silica reaction (ASR) and alkali-carbonation reaction (ACR) in concrete. The presence of TMAH helps to promote the mitigation process of alkali-carbonation reaction (ACR) in concrete with dolomitic aggregates.