sulfate resistance, alkali-silica reaction and freeze-thaw resistance of alkali-activated concretes

Povzetek

The RILEM technical committee TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ conducted a round robin testing programme to determine the validity of various durability testing methods, originally developed for Portland cement based-concretes, for the assessment of the durability of alkali-activated concretes. The outcomes of the round robin tests evaluating sulfate resistance, alkali-silica reaction (ASR) and freeze–thaw resistance are presented in this contribution. Five different alkali-activated concretes, based on ground granulated blast furnace slag, fly ash, or metakaolin were investigated. The extent of sulfate damage to concretes based on slag or fly ash seems to be limited when exposed to an Na2SO4 solution. The mixture based on metakaolin showed an excessive, very early expansion, followed by a dimensionally stable period, which cannot be explained at present. In the slag-based concretes, MgSO4 caused more expansion and visual damage than Na2SO4; however, the expansion limits defined in the respective standards were not exceeded. Both the ASTM C1293 and RILEM AAR-3.1 test methods for the determination of ASR expansion appear to give essentially reliable identification of expansion caused by highly reactive aggregates. Alkali-activated materials in combination with an unreactive or potentially expansive aggregate were in no case seen to cause larger expansions; only the aggregates of known very high reactivity were seen to be problematic. The results of freeze–thaw testing (with/without deicing salts) of alkali-activated concretes suggest an important influence of the curing conditions and experimental conditions on the test outcomes, which need to be understood before the tests can be reliably applied and interpreted.

Ključne besede

alkalijsko aktivirani materiali;sulfatna odpornost;alkalno silikatna reaktivnost;odpornost na zmrzovanje;Rilem TC;alkali-activated materials/geopolymers;sulphate resistance;alkali silica reactivity;freeze-thaw resistance;

Podatki

Jezik: Angleški jezik
Leto izida:
Tipologija: 1.01 - Izvirni znanstveni članek
Organizacija: ZAG - Zavod za gradbeništvo Slovenije
Založnik: E. & F. N. Spon, RILEM Publications
UDK: 620.1/.2
COBISS: 37182979 Povezava se bo odprla v novem oknu
ISSN: 1359-5997
Št. ogledov: 10
Št. prenosov: 0
Ocena: 0 (0 glasov)
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Ostali podatki

Sekundarni jezik: Slovenski jezik
Sekundarne ključne besede: alkalijsko aktivirani materiali;sulfatna odpornost;alkalno silikatna reaktivnost;odpornost na zmrzovanje;Rilem TC;
Komentar vira: Article: 140;
Strani: str. 1-17
Letnik: ǂVol. ǂ53
Zvezek: ǂissue ǂ6
Čas izdaje: Dec. 2020
DOI: 10.1617/s11527-020-01562-0
ID: 19814394
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