Journal ArticleDOI
Effect of activator mix on the hydration and strength behaviour of alkali-activated slag cements
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In this article, the authors examined the setting time and mechanical strength behavior of slag cement pastes activated with different alkaline activators and showed that the initial pH of the alkaline solution plays an important role in the initial slag dissolution.Abstract:
This paper examines on the setting time and mechanical strength behaviour of slag cement pastes activated with different alkaline activators. For this purpose three alkaline solutions were used: waterglass solution (27% SiO2, 18 % Na2O and 55% H2O), NaOH and Na2CO3, maintaining always a constant concentration of Na2O (4% by mass of slag). The solutions were prepared with mixes of 0%, 80%/20% and 20%/80%. The activation process was studied at early ages by conduction calorimetric and fourier transform infrared spectroscopy (FTIR). Results show that the initial pH of the alkaline solution plays an important role in the initial slag dissolution. However the factor playing a decisive role in the acceleration or delay of setting times and in the development of mechanical strengths is the nature of the anion present in the solution. SiO4 2− ions act as an accelerator of the setting time, but CO3 2− ions delay the setting time.read more
Citations
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Influence of slag chemistry on the hydration of alkali-activated blast-furnace slag — Part I: Effect of MgO
TL;DR: In this article, the microstructure of three AASs with MgO contents between 8 and 13.5% were investigated and the formation of C(−−A)−S−H and a hydrotalcite-like phase was observed in all samples by X-ray diffraction (XRD), thermal analysis (TGA) and scanning electron microscopy (SEM) techniques.
Journal ArticleDOI
Influence of activator type on hydration kinetics, hydrate assemblage and microstructural development of alkali activated blast-furnace slags
TL;DR: In this article, the hydration of two slags with different Al 2 O 3 contents activated with sodium hydroxide and hydrous sodium metasilicate (commonly named water glass) was studied using a multi-method approach.
Journal ArticleDOI
Recent progress in low-carbon binders
Caijun Shi,Bo Qu,John L. Provis +2 more
TL;DR: The development of low-carbon binders has been recognized as a means of reducing the carbon footprint of the Portland cement industry, in response to growing global concerns over CO2 emissions from the construction sector as mentioned in this paper.
Journal ArticleDOI
Effect of Shrinkage-reducing Admixtures on the Properties of Alkali-activated Slag Mortars and Pastes
Marta Palacios,Francisca Puertas +1 more
TL;DR: In this paper, the effect of polypropylenglycol on the dimensional stability of waterglass-activated slag mortars was studied, and the pore structure of the mortars and the mineralogical composition and microstructure of the pastes were analyzed.
Journal ArticleDOI
Use of glass waste as an activator in the preparation of alkali-activated slag. Mechanical strength and paste characterisation
TL;DR: In this paper, the feasibility of using urban and industrial glass waste as a potential alkaline activator for blast furnace slag (AAS) was explored, and three activators were prepared with three different activators: waterglass, a NaOH/Na 2 CO 3 mix and the solutions resulting from dissolving glass waste.
References
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Journal ArticleDOI
Structure of Calcium Silicate Hydrate (C‐S‐H): Near‐, Mid‐, and Far‐Infrared Spectroscopy
TL;DR: In this paper, the mid-, near-, and far-infrared (IR) spectra of synthetic, single-phase calcium silicate hydrates (C-S-H) with Ca/Si ratios (C/S) of 0.41-1.2 were analyzed.
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Factors affecting the strength of alkali-activated slag
TL;DR: In this article, the effect of several factors on the strength of alkali activated slags has been investigated, and the optimum range for each factor is suggested through reviewing previous work and their recent results of a full factorial range strength study.
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Sodium silicate-based, alkali-activated slag mortars: Part I. Strength, hydration and microstructure
A.R Brough,Alan Atkinson +1 more
TL;DR: Alkali activation of ground granulated blast furnace slag with sodium silicate gave clinker-free binders, with high strength and early strength development, although set times were short and somewhat variable as mentioned in this paper.
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Alkali-activated slag mortars: Mechanical strength behaviour
TL;DR: In this paper, the joint influence of a series of factors (specific surface of slag, curing temperature, activator concentration, and the nature of the alkaline activator) on the development of mechanical strengths in alkaline-activated slag cement mortars was investigated.
Journal ArticleDOI
A calorimetric study of early hydration of alkali-slag cements
Caijun Shi,Robert L. Day +1 more
TL;DR: In this paper, the authors examined the early hydration of alkali-slag cements activated by different sodium compounds, such as NaOH, NaCO3, Na2SiO3 and NaF, at 25 and 50 °C.