Detailed investigation of ACR in concrete with silica-free dolomite aggregate

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

Povzetek

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.

Ključne besede

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;

Podatki

Jezik:	Angleški jezik
Leto izida:	2019
Tipologija:	1.01 - Izvirni znanstveni članek
Organizacija:	UL FGG - Fakulteta za gradbeništvo in geodezijo
UDK:	691
COBISS:	8799841
ISSN:	0950-0618
Št. ogledov:	323
Št. prenosov:	147
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarne ključne besede:	alkalno karbonatna reakcija;ACR v betonu;dolomitni agregat brez kremena;mikrostrukturne preiskave;reakcijski mehanizem;
Vrsta dela (COBISS):	Članek v reviji
Strani:	str. 325-336
Zvezek:	ǂLetn. ǂ216
Čas izdaje:	avg. 2019
DOI:	10.1016/j.conbuildmat.2019.04.260
ID:	12649786