Long Term Performance of Alkali Activated Slag Concrete

Wardhono, Arie; Law, David W.; Molyneaux, T

doi:10.3151/jact.13.187

Cited by 37 publications

(13 citation statements)

References 13 publications

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“… SiO 2 / Na 2 O ‐mole ratio and equivalent Na 2 O ‐content of the applied activator in the alkali‐activated slag ( AAS )‐concrete in comparison to literature references …”

Section: Precursor Materials and Concrete Compositionmentioning

confidence: 99%

Shrinkage and creep behavior of an alkali‐activated slag concrete

Dehn

2017

Structural Concrete

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In this paper, experimental results about the shrinkage and creep behavior of an alkali‐activated slag concrete (AAS‐concrete) are presented. The autogenous shrinkage of AAS‐concrete is pronounced at a relatively high water to binder ratio of 0.41. The ultimate value of autogenous shrinkage is determined to be higher than that of high‐strength concrete (HSC). The observed self‐desiccation at a later concrete age can be one of the reasons for the autogenous shrinkage. In a drying environment of 65% relative humidity AAS‐concrete exhibits a significantly higher total shrinkage compared to normal‐strength concrete composed of Portland cement. In the contrary to normal and HSC carbonation shrinkage must not be neglected for AAS‐concrete in the early concrete age. The sum of drying and carbonation shrinkage develops much more rapidly for AAS‐concrete in the first weeks after the beginning of drying. Based on the experimental results the shrinkage behavior of AAS‐concrete cannot be predicted by conventional models. The creep behavior of the AAS‐concrete was investigated under sealed and unsealed conditions. The creep coefficients for both conditions are higher than those calculated when using conventional models.

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“… SiO 2 / Na 2 O ‐mole ratio and equivalent Na 2 O ‐content of the applied activator in the alkali‐activated slag ( AAS )‐concrete in comparison to literature references …”

Section: Precursor Materials and Concrete Compositionmentioning

confidence: 99%

Shrinkage and creep behavior of an alkali‐activated slag concrete

Dehn

2017

Structural Concrete

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“…In addition, in comparison with OPC, production of AAS can result in considerable reduction in the embodied energy and carbon dioxide emissions (Jiang et al 2014). On the other hand, AAS materials present challenges, such as high shrinkage, rapid carbonation, formation of salt efflorescence, potential alkali-silica reaction, causticity of activator (safety and health issues), and lacks of relevant material testing standardization Douglas et al 1992;Juenger et al 2011;Shi et al 2005;Wardhono et al 2015;Ye et al 2014), that still needs to be addressed before wider application of these alternative binders. While the aforementioned engineering properties of AAS are strongly associated with its hydrated phases (Duxson et al 2005;Juenger et al 2011), they are also intimately related to the composition and properties of slag, as well as nature and dosage of activators.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Analysis of Phase Assemblage and Chemical Shrinkage of Alkali-Activated Slag

Radlińska

2016

ACT

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This paper presents a quantitative analysis of hydrated phase assemblage and chemical shrinkage of alkali-activated slag (AAS) as a function of pH and modulus (n= SiO 2 /Na 2 O molar ratio) of activator. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and thermodynamic modeling, provide a comprehensive characterization of the phase assemblages and distribution in AAS microstructure. The main hydration products in AAS are calcium-alumina-silicate-hydrate (C-A-S-H) and hydrotalcite-type phases, while the formation of other hydrates is activator-dependent. For NaOH-activated slag, hydration products are preferentially formed around slag particles showing a hydrated rim, while for sodium silicate-activated slag, hydration products are initialized at both slag surface and inter-particle spaces simultaneously. However, a dark hydrated rim whose composition is similar to that of alkali-aluminosilicate-hydrate was observed around unhydrated slag in aged AAS. It indicates that the composition and spatial distribution of hydrates in AAS microstructure is heterogeneous, which cannot be predicted by thermodynamic modeling. The chemical shrinkage of AAS was quantified using buoyancy method and backscattered image analysis. The average chemical shrinkage of AAS is about 0.1211 ml/g slag and increases with the increasing modulus and pH of activator. The chemical shrinkage of AAS is about twice larger than that of portland cement, which may be attributed to the limited formation of expansive crystalline phases, such as ettringite and portlandite.

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“…Encouragingly, previous research [5][6][7][8][9] confirms that alkali-activated slag concrete (AASC) offers a range of performance benefits, such as high mechanical strength at early stages of curing, excellent acid-resistant characteristics, good resistance to freeze-thaw cycles and resistance to elevated temperatures. As such, the production and performance of AASC have been a highly active area of academic and industrial research over the past decades.…”

Section: Introductionmentioning

confidence: 99%

Establishment of a preconditioning regime for air permeability and sorptivity of alkali-activated slag concrete

Yang

Chen

Magee

et al. 2016

Cement and Concrete Composites

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This study reports an experimental investigation designed to assess the influence of near-surface moisture contents on permeation properties of alkali-activated slag concrete (AASC). Five different drying periods (5, 10, 15, 20 and 25 days) and three AASC and normal concretes with compressive strength grades ranging from C30 to C60 were considered. Assessment of moisture distribution was achieved using 100 mm diameter cores with drilled cavities. Results indicate that air permeability of AASC is very sensitive to the moisture content and its spatial distribution, especially at relative humidity above 65%. To control the influence of moisture on permeation testing, the recommendation of this paper is that AASC specimens should be dried in controlled conditions at 40 o C for 10 days prior to testing. It was also concluded from this study that AASC tends to perform less well, in terms of air permeability and sorptivity, than normal concrete for a given strength grade. This conclusion reinforces the need to further examine AASC properties prior to its widespread practical use.

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Long Term Performance of Alkali Activated Slag Concrete

Cited by 37 publications

References 13 publications

Shrinkage and creep behavior of an alkali‐activated slag concrete

Shrinkage and creep behavior of an alkali‐activated slag concrete

Quantitative Analysis of Phase Assemblage and Chemical Shrinkage of Alkali-Activated Slag

Establishment of a preconditioning regime for air permeability and sorptivity of alkali-activated slag concrete

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