Influence of seawater concentration on alkali-silica reaction of seawater sea-sand concrete: Mimicking through NaCl solution and recycled glass aggregate

Abstract

Seawater sea-sand concrete (SSC) is one environment-friendly and promising construction material. Nevertheless, limited research shed favorable light on alkali-silica reaction (ASR) of SSC. This work provided a novel insight regarding the fast test method that (i) the recycled glass aggregate (RGA) was used for fast assessing the effect of seawater concentration on ASR, reusing its characteristic resource; (ii) the NaCl solutions with different concentrations were used to mimic different salinities of sea waters; and (iii) a modified curing method was adopted. The results showed that the NaCl solution could be used for assessing ASR risk of SSC instead of seawater. The specimens mixed with twice and above the sodium concentration of seawater would exhibit ASR expansion, strength reduction, coarsening of nanopore distribution, and the cracks on the macro and micro levels. However, the change of NaCl concentration scarcely affected the composition and content of hydration products. Additionally, with increasing the mixing Na+ concentration, the ASR crack would firstly appear in the interface between the cement paste layer and the glass layer, and then developed in the internal zone of RGA matrix with different hardness, elastic modulus, and Si contents based on the destroyed degree.