Efficient Utilization of Activated High-Grade Ultrafine Limestone Powder as Supplementary Cementitious Material

Reasonable allocation of limestone resources is of great significance for accelerating the development of high quality in the limestone industry. An activator (AT) was prepared by compounding FA-DEA (esterification of diethanolamine and fumaric acid) with other organic/inorganic multicomponents. The influence of AT on the dispersion of high-grade limestone (H-LS) ball milling was studied. Based on the results, the application performance and mechanism of adding high-grade limestone powder (H-LSP) and high-grade limestone powder with AT (H-LSP + AT) in cement-based materials were investigated. The results showed that when 0.5% AT was added during the H-LS ball milling process, it not only reduced the coverage of H-LSP on steel balls by about 50.1% but also had an excellent dispersion effect on the agglomerated H-LSP. Further results confirmed that the cement paste with H-LSP + AT had longer setting time and less fluidity loss. In addition, the mortar with 10% and 5% H-LSP + AT exhibited significant early and late compressive strength, respectively. This may mainly be due to the positive effect of finer H-LSP + AT on cement hydration. Simultaneously, the filling function and forming new phase of carboaluminate (C3A·CaCO3·11H2O) also made hydration products more compact. Therefore, this research provides important theoretical support for the application of limestone as supplementary cementitious material.