Water-blocking nano-composite cement-based grouting materials

Abstract

With the rapid development of underground engineering construction such as hydropower projects, mines, tunnels, etc., underground hydrodynamic-related problems have become a more prominent challenge. In view of the shortcomings of the current hydrodynamic grouting materials, a systematic analysis for the preparation, performance, and water-blocking reinforcement mechanism of a new nano-composite cement-based dynamic water grouting material was carried out by a comprehensive approach of theoretical analysis, laboratory test, field test, and microscopic study. Utilizing the “synergistic hydration” effect produced by compounding ordinary Portland cement and sulfoaluminate cement, aimed at the harmonization of rheological and solidification characteristics of grouting material, a new nano-composite cement-based grouting material (NCC) was developed by mixing with water-reducing agent (JC), early strength agent (VT), nano-materials (SiO2), and cellulose (QC). The properties of the NCC, such as rheology, fluidity, pumpability, setting time, compressive strength, and anti-scour performance were carefully examined by laboratory tests. The NCC product was successfully field tested. Finally, an integrated analysis of X-ray diffraction and scanning electron microscopy was used to investigate the mechanism of water-blocking reinforcement, and consequently, it led to a water-blocking reinforcement process model of nano-composite cement slurry. The research result, i.e., NCC product, provided a new solution to effectively resolve the problem of gushing water disaster in the management of underground engineering construction.