Dicalcium silicate hydration behavior in the presence of Na2CO3 and water glass
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This study focuses specifically on the β-C2S polymorph hydrated in deionized water and with the presence of Na2CO3 (2 M) and of water glass. Dicalcium silicate was prepared from calcium carbonate and gel silica. The salts’ activators were dissolved in water and then added to synthesized dicalcium silicate. Hydrated samples after different curing time (from 2 to 90 days) were characterized by X-ray diffraction, infrared spectroscopy, isothermal conduction calorimetry, and scanning electron microscopy, whereas the compressive strength was operated after 28 and 90 days. The results showed that the contact of belite with liquid phase during hydration is strongly influenced by the existence of alkalis. The early hydration was accelerated and this can be clearly viewed during the dissolution of C2S which becomes more fast with a decrease of C2S peaks and the increase of calcium silicate hydrates C–S–H product as well as calcium silicate hydrates containing sodium C–(N)–S–H gel-like. This influence is mainly manifested on the mechanical properties of samples by enhancement in early compressive strength.
KeywordsDicalcium silicate Alkali activator Hydration Water glass Na2CO3
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On behalf of all authors, the corresponding author states that there is no conflict of interest.
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