Investigation of elevated temperature on compressive strength and microstructure of alkali activated slag based cements

Yadollahi, Mehrzad Mohabbi; Dener, Murat

doi:10.1080/19648189.2018.1557562

Cited by 29 publications

(9 citation statements)

References 31 publications

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“…Our results represent a significant advancement as respect to previous literature where, generally, a decrease of mechanical properties is observed after high-temperature exposure of alkali-activated samples [13,[25][26][27][28][29]42,43,61,67,69]. Only few authors reported a compressive strength increase [27,62,69]. Even if direct comparisons are difficult to perform, due to huge variety of compositions and processing parameters, Table 3 summarizes the key features of some recent papers dealing with high-temperature exposure of alkaliactivated materials, in order to highlight literature results and the advances achieved in this research.…”

Section: Mechanical Propertiessupporting

confidence: 71%

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Alkali-activated refractory wastes exposed to high temperatures: development and characterization

Coppola

Tardivat

Richaud

et al. 2020

Journal of the European Ceramic Society

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The feasibility to prepare alkali-activated materials starting from refractory wastes and their properties after exposure to high temperatures (800, 1000, 1200 and 1400 °C) were investigated. Two different aluminosilicate wastes were used: chamotte (CH, mainly composed of corundum, mullite and andalusite) and alumina-zirconia-silica (AZS, composed by baddeleyite, corundum and amorphous silica). Very high mechanical properties were achieved in both cases (28-days compressive strength of approx. 70 and 60 MPa for CH-and AZS-based pastes, respectively). Then, alkali-activated pastes were exposed to high temperatures. For both kinds of samples, a sharp increase of mechanical properties was obtained after exposure to 800 and 1000 °C thanks to the matrix densification. Above 1000 °C viscous sintering occurs leading to a further increase of mechanical properties. AZS-based materials were able to withstand high temperatures up to 1400 °C while CH-based pastes mechanical properties decrease at 1400 °C due to andalusite decomposition.

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Section: Mechanical Propertiessupporting

confidence: 71%

“…-1 are related to Si-O-Si and Si-O-Al bond vibrations typical of geopolymers[26,61,42,62]. Moreover, the peaks at 775 cm -1 and 605 cm -1 correspond to AlO 4 tetrahedra and AlO 6 octahedra vibrations, respectively.…”

mentioning

confidence: 96%

Alkali-activated refractory wastes exposed to high temperatures: development and characterization

Coppola

Tardivat

Richaud

et al. 2020

Journal of the European Ceramic Society

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“…AASC offers favorable properties, some of which include durability in aggressive and acidic environments [4,17]. Numerous studies have been performed to investigate the diverse characteristics of AASC, such as the mechanical properties [7,[18][19][20], shrinkage [21,22], carbonation [23,24], and elevated temperature endurance [25]. The main hydration product of AASC is calcium aluminum silicate hydrate (C-A-S-H) gel, with a quite quick setting time and a low Ca/Si ratio compared with OPC concrete [13,20].…”

Section: Introductionmentioning

confidence: 99%

Mix Design Effects on the Durability of Alkali-Activated Slag Concrete in a Hydrochloric Acid Environment

2021

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Because of its high strength, energy reduction, and low environmental impact, researchers have encouraged considering alkali-activated slag concrete (AASC) as a potential alternative to conventional concrete. In this study, the impact of mix design parameters on the durability of AASC, made with ground granulated blast furnace slag and activated with different alkaline solutions (NaOH, KOH, and Na2SiO3) immersed up to six months in a hydrochloric acid bath with pH = 3, has been investigated. A total of 13 mix designs were made in a way that, in addition to the type of alkaline solution, considered three other parameters, namely the molarity of alkaline solutions, the weight ratio of alkaline solutions to slag, and the weight ratio of alkaline solutions to sodium silicate. Visual inspections displayed that the AASC samples almost remained intact after exposure to an HCl acid solution with pH = 3 for up to 6 months, while the OPC sample experienced deleterious deterioration. The results clearly show that AASC outperformed OPC concrete when it comes to durability in an HCl acid solution. The strength reduction and weight loss of AASC compared with OPC concrete were approximately one-tenth and one-fifth, respectively. The AASC samples containing potassium hydroxide showed a higher strength reduction and weight loss in the HCl acid solution than the samples made with sodium hydroxide.

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“…There is not organic matter in the slag [4]. In the literature, there are studies on the durability [5][6][7][8][9][10] and compressive strength [11][12] changes of geopolmer concrete produced using ferrorchrome slag depending on the alkali activator types. However, information about curing conditions and times are insufficient.…”

Section: Introductionmentioning

confidence: 99%

Compressive Strength Prediction of Ferrochrome Slag Based Geopolymer Concretes Produced Under Different Curing Conditions by Using Prediction Methods

Kalkan¹,

Karakoç²,

Özcan³

2021

Deu Muhendislik Fakultesi Fen Ve Muhendislik

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In this study, compressive strength (CS) values of ferrochrome slag (FS) based geopolymer concretes in different curing conditions were investigated. Ground FS was activated with the mixture of sodium hydroxide and sodium silicate. The silica modulus (Ms) of the geopolymer concrete samples were selected as 1.25, 1.50 and 1.75. Also, samples were prepared by substituting 0%, 10% and 20% silica fume (SF) replacement the FS. Thus, 9 groups geopolymer concrete samples were produced. The CS values of the samples were determined on different curing times (24, 48, 72 and 96 hours) and curing temperatures (23, 40, 60, 80 and 100 °C). At the same time, multilayer perceptron neural network (MLPNN), extreme learning machine neural network (ELMNN) and M5 model tree were modeled for the CS prediction of the samples, the predict and experimental results were compared. According to the experiment results, it was determined that the CS values generally increased as the curing time increased, but with the addition of SF, the CS values generally decreased. The highest CS was obtained in the sample containing 100% FS that had silica modulus of 1.25 and cured at 100 °C for 24-48-72 or 96 hours. The R 2 values of MLPNN, ELMNN and M5 model tree in testing phase were 0.956, 0.935 and 0.922, respectively. MLPNN, the model that gave the best predict result, had root mean square error (RMSE) of 0.723 and normalized root mean square error (NMRSE) of 26.485 in testing.

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Investigation of elevated temperature on compressive strength and microstructure of alkali activated slag based cements

Cited by 29 publications

References 31 publications

Alkali-activated refractory wastes exposed to high temperatures: development and characterization

Alkali-activated refractory wastes exposed to high temperatures: development and characterization

Mix Design Effects on the Durability of Alkali-Activated Slag Concrete in a Hydrochloric Acid Environment

Compressive Strength Prediction of Ferrochrome Slag Based Geopolymer Concretes Produced Under Different Curing Conditions by Using Prediction Methods

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