Effect of sodium carboxymethyl celluloses on water-catalyzed self-degradation of 200 °C-heated alkali-activated cement

This paper investigates the usefulness of sodium carboxymethyl celluloses (CMC) in promoting self-degradation of 200 °C-heated sodium silicate-activated slag/Class C fly ash cementitious material after contact with water. CMC emitted two major volatile compounds, CO2 and acetic acid, creating a porous structure in cement. CMC also reacted with NaOH from sodium silicate to form three solid reaction products, disodium glycolate salt, sodium glucosidic salt, and sodium bicarbonate. Other solid reaction products, such as sodium polysilicate and sodium carbonate, were derived from hydrolysates of sodium silicate. Dissolution of these products upon contact with water generated heat that promoted cement's self-degradation. Thus, CMC of high molecular weight rendered two important features to the water-catalyzed self-degradation of heated cement: one was the high heat generated in exothermic reactions in cement; the other was the introduction of extensive porosity into cement.