Soluble silicates have a long, successful history in chemical grouting and other geotechnical applications. For stabilizing sandy or loose soils, silicate solutions (usually diluted) are injected into the ground and reacted with materials that harden or gel the silicate. There are a variety of inorganic and organic setting agents. Inorganic setting agents, such as calcium chloride, form the strongest materials, but gel times are more difficult to control. Organic setting agents, such as propylene carbonate, are easier to control, but gel strengths are somewhat lower.