Investigation of the Mixed Super-Early-Strength Agent of Mechanical and Hydration Properties of Concrete

This paper discusses the potential of adding a self-made super-early-strength agent to produce quick-setting, quick-hardening, and high-strength concrete. A super-early-strength agent is prepared by mixing triethanolamine (TEA), aluminum sulfate (Al2(SO4)3·18H2O), formic acid (HCOOH), and sodium fluoride (NaF) with a water-reducing agent in different proportions. In this paper, the effects of super-early-strength agent ratio and dosage, water–binder ratio, silica fume content, and cementitious material content on the setting time and compressive strength of high-strength concrete were studied. The hydration characteristics were evaluated by X-ray diffraction (XRD) and TG-DSC thermal analysis. The results show that the high-strength concrete prepared by 42.5R ordinary Portland cement mixed with appropriate amount of silica fume and self-made super-early-strength agent has a compressive strength of 10 MPa in 6 h, a compressive strength of 40 MPa in 1 day, a compressive strength of not less than 80 MPa in 28 days, and a compressive strength of not shrinking in 180 days. Using conventional raw materials and general process methods, the concrete prepared according to the preparation method of this experiment can significantly shorten the setting time and improve the compressive strength. However, it is difficult to form concrete when the amount of super-early-strength agent is too large. Nevertheless, this study provides a theoretical basis for large-scale and high-value utilization of the potential of super-early-strength agents and development to improve efficiency. At the same time, it provides a reference for the application of coating technology in rapid repair engineering.