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.
About: This article is published in Cement and Concrete Research.The article was published on 1999-08-01. It has received 520 citations till now. The article focuses on the topics: Ground granulated blast-furnace slag & Slag.
Citations
More filters
TL;DR: Aluminosilicate-based alkaline cements have been classified into five categories as discussed by the authors, and the key advances made in the understanding of synthetic gels are discussed, which ultimately finds hybrid cements to be technologically viable materials for contemporary construction.
1,104 citations
TL;DR: In this paper, the synthesis of alkali-activated binders from blast furnace slag, calcined clay (metakaolin), and fly ash is discussed, including analysis of the chemical reaction mechanisms and binder phase assemblages that control the early-age and hardened properties of these materials.
Abstract: The development of new, sustainable, low-CO2 construction materials is essential if the global construction industry is to reduce the environmental footprint of its activities, which is incurred particularly through the production of Portland cement. One type of non-Portland cement that is attracting particular attention is based on alkali-aluminosilicate chemistry, including the class of binders that have become known as geopolymers. These materials offer technical properties comparable to those of Portland cement, but with a much lower CO2 footprint and with the potential for performance advantages over traditional cements in certain niche applications. This review discusses the synthesis of alkali-activated binders from blast furnace slag, calcined clay (metakaolin), and fly ash, including analysis of the chemical reaction mechanisms and binder phase assemblages that control the early-age and hardened properties of these materials, in particular initial setting and long-term durability. Perspectives fo...
862 citations
TL;DR: In this paper, ground fly ash (GFA), with a median particle size of 10.5μm, was used as source material for making geopolymers cured at room temperature, and compressive strength tests and microstructure observations using SEM, EDX, XRD and FTIR were performed.
755 citations
Cites methods from "Alkali-activated slag mortars: Mech..."
...The most commonly used alkaline activators are NaOH and KOH [5–9]....
[...]
TL;DR: The activation of fly ash/slag pastes with NaOH solutions has been studied in this paper, where the authors established the equations of the models describing the mechanical behaviour of these pastes as a function of the factors and levels considered.
745 citations
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.
685 citations
Additional excerpts
...findings reported in other studies [8,10,27–32]....
[...]
References
More filters
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.
558 citations
TL;DR: In this paper, the authors summarized the advantageous and disadvantageous properties of alkali-activated slag cement and concrete by reviewing previously published work in English, Russian and Chinese, and discussed practical problems and theoretical questions concerning alkaline activation.
Abstract: This paper summarizes the advantageous and disadvantageous properties of alkali-activated slag cement and concrete by reviewing previously published work in English, Russian and Chinese. Practical problems and theoretical questions are discussed. Topics for future work in this field are suggested. The practical problems mentioned are quick setting, the possibility of alkali—aggregate reaction, and the occurrence of efflorescence, shrinkage, microcracks and strength variation. The theoretical questions discussed concerning alkaline activation include the roles of the alkaline anion and cation, the nature of the hydration products, microstructural development and the setting and hardening mechanisms.
395 citations
TL;DR: The degree of reaction was determined by means of the heat of hydration after the induction period and the reaction mechanism determined for AAS pastes was a diffusion mechanism and their activation energy was 57.6 KJ/mol.
179 citations
DOI•
01 May 1989
TL;DR: In this paper, the authors present the latest publications dealing with the development and practical application of activated slag clinker-free concretes with special reference to less known papers and recent information.
Abstract: This paper will present the latest publications dealing with the development and practical application of activated slag clinker-free concretes with special reference to less known papers and recent information. The finely ground slag, usually granulated blast furnace slag, is activated by the solution of sodium or potassium hydroxide, carbonate, or preferably silicate (soluble glass) of appropriate concentration and silicate modulus. The difference of microstructure between portland cement concrete and alkali-activated slag concrete and its consequences for their properties, especially for very high strengths and corrosion resistance, is discussed. The use of nonstandard aggregate and other industrial by-products, as well as the low costs of this type of concrete are also presented. Examples of applications of alkali-activated slag concrete of different composition are given. Some problems connected with the present use of alkali-activated concrete are discussed together with the most promising applications for the future.
122 citations
DOI•
01 May 1989
TL;DR: In this paper, the effect of different curing conditions on the performance of AAS pastes, mortars, and concrete was investigated, and some microscopic and x-ray diffraction analyses were made on the tested samples.
Abstract: This paper investigated the effect of different curing conditions on the performance of alkali-activated slag (AAS) pastes, mortars, and concrete. The temperature range is from -15 to 105 C. The storing conditions were underwater and at relative humidities of 100, 70, and 50 percent. After storing under these conditions, the compressive strengths were determined, and some microscopic and x-ray diffraction analyses were made on the tested samples. The AAS mortars and concretes perform very well even after an extremely strong heat treatment followed by storing at a low relative humidity. At normal temperature, the drop from 100 to 70 percent relative humidity does not affect the strength properties of the concrete. The AAS concrete can be heat-treated immediately after casting without any detrimental losses in strength. Storage in a dry climate does not have a strong influence on the strength development because the AAS binders form a very dense matrix with a large part of closed pores. Some results from industrial production of concrete with AAS binders are also presented. The results prove the suitability of AAS for the precast industry.
29 citations