Influence of Dosage and Modulus on Soluble Sodium Silicate for Early Strength Development of Alkali-Activated Slag Cements

Abstract

In world practice, the need for high-strength concrete with an intensive gain of early strength is due to an increase in requirements for characteristics of concrete and the desire to shorten the construction period. Alkali-activated cement, based on soluble sodium silicates (SSS), can demonstrate high strength and rapid gain due to the nano-modifying effect of amorphous silica present in SSS. However, the problem with the effective use of such cement compositions is unsatisfactory short setting times. This work investigates the effect of modifying admixtures on the structure formation of alkali-activated slag cement (AASC), its physical and mechanical properties depending on characteristics of SSS and the basicity of the aluminosilicate component (precursor), which was changed by the ratio of the ordinary Portland cement (OPC) clinker and granulated blast furnace slag (GBFS). A positive synergistic effect was noticed from glycerol and trisodium phosphate, as the components of a complex admixture, to control the setting of AASC. This resulted in extending the initial setting time from 1 to 5 min to the values of 21–72 min. The compressive strength of 21–26.3 MPa by 3 h, 36.5–43.4 MPa by 1 day, and 84.7–117.1 MPa by 28 days was obtained. Proper shrinkage deformations were equal to 0.47–0.6 mm/m. It was shown that with an increase in the basicity of the aluminosilicate component, the properties of AASC increased both in the early and late stages of hardening.

Design Characterization and Incorporation of the Alkaline Alumino-Silicate Binder in Temperature Insulating Composites

“…The durability of the ancient concretes and the similarity of their structure with that of the alkali-activated cement concretes allowed us to predict the high durability of the last ones. Thus, the effectiveness and high performance properties of alkali-activated materials, such as increased strength [4], heat resistance [5], corrosion resistance [6], and freeze-thaw resistance [7], have been confirmed by over 65 years experience of their service.…”

Design, Characterization, and Incorporation of the Alkaline Aluminosilicate Binder in Temperature-Insulating Composites

“…The durability of ancient concretes and the similarity of their structure to that of alkali-activated cement concretes allowed us to infer their high durability. The excellent performance properties of alkali-activated materials, such as their high strength and heat, corrosion, and freezethaw resistance [4][5][6][7], have been confirmed by over 65 years' experience of their use. The composition of zeolite-like products is determined by structural features of aluminosilicate components (precursor), alongside their composition, the applied curing conditions, the rate of chemical reactions, and the binder design [8][9][10][11][12].…”