Development of Self-Swelling Tablets as a Substitute for Soundless Cracking Demolition Agents

Abstract

The low viscosity of soundless cracking demolition agent (SCDA) slurries makes them difficult to use on rock and concrete breakage in horizontal and up holes, or wet holes. In this paper, self-swelling tablet cartridges are developed by use of additives including adhesive, wetting agent, water absorbent, and activator to SCDA powder through newly developed production technologies. The dosages of adhesive and wetting agent were optimized in the process of powder granulation. Their optimal addition amounts are 3.17% and 11.81%. The self-swelling tablet (SST) experiments and optimization tests show the hardness of SST improved with an increase in pressure and mold filling height. Subsequently, laboratory tests were conducted to determine the influence of the contents of water absorbent and activator on the SST water absorption, reaction temperature, and expansion pressure. The water absorption of SST was found to improve with an increase in water absorbent amount and particle size of the granules. The optimum dosage of the water absorbent is 10%. Based on the laboratory experiments, the optimum amount of additives in the SST is 5% for its best performance. The production of SST cartridges is in a safer and healthier environment compared to SCDA powder cartridges, and its production can be automated to reduce labour cost. Finally, the introduction of SST cartridges expands the scope of application of the SCDA to up holes, horizonal holes, and wet holes.