Comparison of long term performance between alkali activated slag and fly ash geopolymer concretes

Wardhono, Arie; Gunasekara, Chamila; Law, David W.; Setunge, Sujeeva

doi:10.1016/j.conbuildmat.2017.03.153

Cited by 200 publications

(78 citation statements)

References 30 publications

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“…Compressive strength shows no decrease, while tensile splitting strength and elastic modulus, shows a decrease over time, being the highest for the elastic modulus. This is consistent with the few results reported in literature, that also show the biggest decrease for elastic modulus and (almost) no decrease for compressive strength . The decrease is stabilizing and becoming smaller after the age of 91 days for mix S50 and after the age of 193 days for mix S100.…”

Section: Discussionsupporting

confidence: 93%

“…These samples were water‐cured for 6 day after being demoulded and were subsequently kept at room temperature until being tested. However, for alkali‐activated FA concrete, heat‐cured at 80°C for 24 hr and subsequently kept at room temperature until testing, Wardhono et al did not observe a decrease of properties over time. It is expected that the reported phenomena of a decrease in material properties might be related to the material composition, for example, presence of BFS, and/or the type of curing conditions, for example, presence of water.…”

Section: Introductionmentioning

confidence: 96%

“…On the other hand, sealed and bath cured samples did not exhibit this reduction and even showed an increase of compressive strength over time. Wardhono et al reported a reduction of flexural strength and elastic modulus for AAS concrete, while compressive strength was approximately constant over time. The elastic modulus of AAS concrete showed a 43% drop from 28 to 540 days.…”

Section: Introductionmentioning

confidence: 99%

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Time‐dependent material properties and reinforced beams behavior of two alkali‐activated types of concrete

Prinsse

Hordijk

et al. 2019

Structural Concrete

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This paper presents an experimental study on the development of material properties over time (up to around 2 years) and the structural behavior of reinforced beams, for two types of alkali-activated concrete (AAC). Compressive strength, flexural strength, tensile splitting strength, elastic modulus, and flexural behavior of reinforced beams are investigated. Tested material properties of AAC are compared with the properties of conventional concrete, as predicted by Eurocode. For the mixes of AAC and the conventional concretes with the same 28 days compressive strength, flexural and tensile splitting strength at 28 days are found to be similar, whereas the elastic moduli of AAC mixtures is up to 30% lower than those of conventional concrete. Related to the long term behavior, after 28 days moistcuring and subsequently exposing AAC specimens to laboratory conditions (50% RH/20 C), a reduction of flexural strength, tensile splitting strength and elastic modulus, is observed. Structural behavior of the reinforced AAC beams in fourpoint bending test seems not to be affected significantly by the observed decrease in material properties, and is found to be similar to that of conventional concrete beams. The acquired results indicate that the observed decrease of material properties over time might be related to drying (moisture loss). However, more research is needed to understand the phenomenon, especially related to the aimed structural application and safe upscaling of AAC. K E Y W O R D Salkali-activated concrete, alkali-activated slag, reinforced alkali-activated concrete beams, stiffness, strength, structural behavior, time-dependent behavior

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Time‐dependent material properties and reinforced beams behavior of two alkali‐activated types of concrete

Prinsse

Hordijk

et al. 2019

Structural Concrete

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“…In our previous study, we reported mechanical properties and elastic modulus changes of geopolymer concrete, due to steam curing, it was found that the mechanical properties change and the elastic modulus on geopolymer concrete due to steam curing. Water evaporation and self-desiccation during the heat curing stage was also reported by Wardhono et al [16]. They found that the Si/Al ratio in the matrix decreased with age indicating an on-going geopolymerization process beyond the 90 day time period.…”

Section: Compressive Strengthmentioning

confidence: 66%

The effect of steam curing on chloride penetration in geopolymer concrete

Ekaputri

Mutiara

Nurminarsih³

et al. 2017

MATEC Web Conf.

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Abstract. In this paper, we present the result of our study on the effect of steam curing to chloride ion penetration in geopolymer concrete. Class F fly ash was activated using sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The concrete specimens were then steam-cured at 40ºC, 60ºC, 80ºC and room temperature at 24 hours. The treatment was followed by wet curing for 28 days, and then followed by immersion of all specimens in salt water for the durations of 30, 60, and 90 days. Cylindrical specimens were then prepared for compressive strength, chloride ion penetration, pH, and porosity tests. A 16 mm-steel bar was fixed at the center of the specimen concrete blocks (specimen size: 10cm x 10cm x 15cm). Corrosion probability was determined by conducting Half Cell Potential test. Our result showed that increasing the curing temperature to 80ºC induced chloride ion penetration into the concrete's effective pores, despite improvements in compressive strength. We also found that chloride ingress on the geopolymer concrete increases commensurately with the increase of the curing temperature. The corrosion potential measurement of geopolymer concrete was higher than OPC concrete even if corrosion was not observed in reinforcing. Based on our result, we suggest that the corrosion categorization for geopolymer concretes needs to be adjusted.

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“…Generally, the production process of geopolymer binder is using a specific mixing method where fly ash raw material and alkali activator solution are mixed together with a specific composition, water to solid ratio, and chemical molarity ratio. The alkali activator solution is a blended between sodium hydroxide (NaOH) with a certain molarity with sodium silicate or water glass (Na2SiO3) solutions [7,8,10,11]. However, the drawbacks of this wet mixing method are on the preparation and the mixing process of NaOH solution.…”

Section: Introductionmentioning

confidence: 99%

The effect of water binder ratio on strength development of class C fly ash geopolymer mortar prepared by dry geopolymer powder

Wardhono

2019

MATEC Web Conf.

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The use of geopolymer binder as cement replacement material can reduce the amount of carbon dioxide gas produced during the Portland Cement manufacturing process. However, the main issue of geopolymer binder is in the mixing process of sodium silicate and NaOH which requires specialized knowledge and strict supervision. This paper reports the effect of water binder ratio on strength development of fly ash geopolymer mortar using dry geopolymer powder. Fly ash with high calcium content was used as primary material. The dry geopolymer powder was prepared by wet mixing method which was made by drying a mixture of NaOH solution and limestone for 24 hours. The variations of water to binder ratio were 0.30, 0.35, 0.40, 0.45, and 0.50. Strength properties were measured by compressive strength at the age of 7, 14 and 28 days. The results showed that the water binder ratio significantly affect the strength development of geopolymer mortar prepared by dry geopolymer powder. The water binder ratio of 0.40 gives the highest compressive strength of 10.3 MPa at 28 days. This suggests that the use of dry geopolymer powder on geopolymer mortar production can overcome the difficulties of geopolymer mortar mixing on site.

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Comparison of long term performance between alkali activated slag and fly ash geopolymer concretes

Cited by 200 publications

References 30 publications

Time‐dependent material properties and reinforced beams behavior of two alkali‐activated types of concrete

Time‐dependent material properties and reinforced beams behavior of two alkali‐activated types of concrete

The effect of steam curing on chloride penetration in geopolymer concrete

The effect of water binder ratio on strength development of class C fly ash geopolymer mortar prepared by dry geopolymer powder

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