Abstract
Abstract Alkali-aggregate reaction is a chemical reaction between cement alkalis and some reactive mineral present in some aggregates, leading to concrete expansion and cracking. One kind usually observed and studied in Brazil is the alkali-silica reaction, due to its fast development. There are several methods that are effective to control and mitigate this reaction, and one of them is the partial replacement of cement by mineral additions such as pozzolans like fly-ash, silica fume and slag. In this study, we propose the use of electrical steel slag as a partial replacement of cement, evaluating its effectiveness by NBR 15577:2008, employing different proportions as replacement. It seems that the electrical steel slag, despite its expansive behavior, has been effective in the control of the ASR.
Highlights
Alkali aggregate reaction (AAR) is a chemical reaction, which occurs between alkalis from cement paste and some alkaline reactive minerals in aggregates
This paper evaluates the electric arc furnace steel slag as partial replacement of Portland cement, instead of raw material for cement clinker production, aiming to suppress alkali-silica reaction, based on the methodology established by the Brazilian standard NBR 15577:2008 [26]
The materials used were: high early strength Portland cement with improved resistance to sulphate attack (CP V ARI RS), with characteristics presented in Table 1 and following the features required by NBR 15577:2008; fine grained basalt with volcanic glass scattered throughout the rock; Brazilian standard sand – a reference sand that must be used for cement tests, with characteristics presented in Table 2; and electric arc furnace steel slag
Summary
Alkali aggregate reaction (AAR) is a chemical reaction, which occurs between alkalis from cement paste and some alkaline reactive minerals in aggregates. This reaction form a viscous hygroscopic gel that fills concrete voids leading to damage and reducing the concrete structure life span [1]. Alkali-silicate reaction can be classified as a specific type of ASR, for its resemblance, because low degree of crystalline silicates or amorphous silicates usually develop alkali-silica reaction while highly crystalline silicates develop alkali-silicate reaction [2] In this sense, alkali-silicate is observed in opal, amorphous silica, chert or chalcedony, cristobalite or tridymite, natural volcanic and borosilicate glasses, when reacts with cement alkalis and calcium hydroxide. Low-alkali cement can minimize alkali hydroxide concentration in the concrete pore solution, reducing the potential for expansion. Mo et al [10] say that some lithium salts do not release hydroxyl ions in the pore solution as it reacts, leading to best results
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