Petra Štukovnik (Author), Violeta Bokan-Bosiljkov (Author), Marjan Marinšek (Author)

Abstract

The progress of the alkali-carbonate reaction (ACR) in NaOH or an aqueous environment at elevated tem-perature (60°C) was investigated in concrete prepared with silica-free dolomite aggregate. The resultsobtained show that chemical reactions characteristic for the ACR progressed in all aged concrete systems.In NaOH aged samples, dolomite grains smaller than 2 mm in diameter went through a completededolomitisation process. Additionally, new Mg-Al, Mg-Si and Mg-Al-Si phases were recognized at theaggregate-cement paste interface. The less alkaline environment in the case of H2O-aged samplesresulted in substantially decelerated ACR reaction. Based on observed long-term microstructural andphase changes, a detailed scheme of the ACR in concretes with silica-free dolomite aggregates was pro-posed. It turned out that the soluble Si-source does not necessarily originate from the aggregate itself butrather through the Pozzolanic reaction of cement binder decomposition/regeneration cycle.

Keywords

alkalno karbonatna reakcija;ACR v betonu;Dolomitni agregat brez kremena;mikrostrukturne preiskave;reakcijski mehanizem;alkali carbonate reaction - ACR in concrete;silica-free dolomite aggregate;microstructure investigation;reaction mechanism;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FGG - Faculty of Civil and Geodetic Engineering
UDC: 691
COBISS: 8799841 Link will open in a new window
ISSN: 0950-0618
Views: 323
Downloads: 147
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Other data

Secondary language: Slovenian
Secondary keywords: alkalno karbonatna reakcija;ACR v betonu;dolomitni agregat brez kremena;mikrostrukturne preiskave;reakcijski mehanizem;
Type (COBISS): Article
Pages: str. 325-336
Issue: ǂLetn. ǂ216
Chronology: avg. 2019
DOI: 10.1016/j.conbuildmat.2019.04.260
ID: 12649786