TY - JOUR A1 - Gluth, Gregor A1 - Arbi, K. A1 - Bernal, S. A. A1 - Bondar, D. A1 - Castel, A. A1 - Chithiraputhiran, S. A1 - Dehghan, A. A1 - Dombrowski-Daube, K. A1 - Dubey, A. A1 - Ducman, V. A1 - Peterson, K. A1 - Pipilikaki, P. A1 - Valcke, S. L. A. A1 - Ye, G. A1 - Zuo, Y. A1 - Provis, J. L. T1 - RILEM TC 247-DTA round robin test: carbonation and chloride penetration testing of alkali-activated concretes N2 - Many standardised durability testing methods have been developed for Portland cement-based concretes, but require validation to determine whether they are also applicable to alkali-activated materials. To address this question, RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ carried out round robin testing of carbonation and chloride penetration test methods, applied to five different alkali-activated concretes based on fly ash, blast furnace slag or metakaolin. The methods appeared overall to demonstrate an intrinsic precision comparable to their precision when applied to conventional concretes. The ranking of test outcomes for pairs of concretes of similar binder chemistry was satisfactory, but rankings were not always reliable when comparing alkali-activated concretes based on different precursors. Accelerated carbonation testing gave similar results for fly ash-based and blast furnace slag-based alkali-activated concretes, whereas natural carbonation testing did not. Carbonation of concrete specimens was observed to have occurred already during curing, which has implications for extrapolation of carbonation testing results to longer service life periods. Accelerated chloride penetration testing according to NT BUILD 443 ranked the tested concretes consistently, while this was not the case for the rapid chloride migration test. Both of these chloride penetration testing methods exhibited comparatively low precision when applied to blast furnace slag-based concretes which are more resistant to chloride ingress than the other materials tested. KW - Alkali-activated materials KW - Durability KW - Carbonation KW - Chloride penetration KW - Concrete PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-504045 SN - 1359-5997 SN - 1871-6873 VL - 53 IS - 1 SP - 21 PB - Springer Nature AN - OPUS4-50404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Provis, J. L. A1 - Arbi, K. A1 - Bernal, S. A. A1 - Bondar, D. A1 - Buchwald, A. A1 - Castel, A. A1 - Chithiraputhiran, S. A1 - Cyr, M. A1 - Dehghan, A. A1 - Dombrowski-Daube, K. A1 - Dubey, A. A1 - Ducman, V. A1 - Gluth, Gregor A1 - Nanukuttan, S. A1 - Peterson, K. A1 - Puertas, F. A1 - van Riessen, A. A1 - Torres-Carrasco, M. A1 - Ye, G. A1 - Zuo, Y. T1 - RILEM TC 247-DTA round robin test: mix design and reproducibility of compressive strength of alkali-activated concretes N2 - The aim of RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ is to identify and validate methodologies for testing the durability of alkali-activated concretes. To underpin the durability testing work of this committee, five alkali-activated concrete mixes were developed based on blast furnace slag, fly ash, and flash-calcined metakaolin. The concretes were designed with different intended performance levels, aiming to assess the capability of test methods to discriminate between concretes on this basis. A total of fifteen laboratories worldwide participated in this round robin test programme, where all concretes were produced with the same mix designs, from single-source aluminosilicate precursors and locally available aggregates. This paper reports the mix designs tested, and the compressive strength results obtained, including critical insight into reasons for the observed variability in strength within and between laboratories. KW - Alkali-activated materials KW - Alkali-activated slag KW - Compressive strength KW - Concrete KW - Mix-design PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-489131 SN - 1359-5997 SN - 1871-6873 VL - 52 IS - 5 SP - Article Number 99 PB - Springer Nature AN - OPUS4-48913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winnefeld, F. A1 - Gluth, Gregor A1 - Bernal, S. A. A1 - Bignozzi, M. C. A1 - Carabba, L. A1 - Chithiraputhiran, S. A1 - Dehghan, A. A1 - Dolenec, S. A1 - Dombrowski-Daube, K. A1 - Dubey, A. A1 - Ducman, V. A1 - Yu, J. A1 - Peterson, K. A1 - Stephan, D. A1 - Provis, J. L. T1 - RILEM TC 247-DTA round robin test: sulfate resistance, alkali-silica reaction and freeze–thaw resistance of alkali-activated concretes N2 - 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. KW - Alkali-activated materials KW - Sulfate attack KW - Alkali silica reaction KW - Alkali aggregate reaction KW - Freeze-thaw attack PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-515527 VL - 53 IS - 6 SP - 140 PB - Springer Nature AN - OPUS4-51552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -