The importance of chemical grouting materials for optimum mechanical performance with different soil conditions

Grouting is a frequently used technique for controlling the water inflow and reinforcement of soil and rock. Even though cement-based grouting materials have been well characterized, ongoing improvements of chemical grouting materials create a need to better understand the characteristics of these materials in order to increase the efficiency of grouting applications. The purpose of this study is to characterize three common chemical grouting materials by exploring their mechanical performance under varying initial soil conditions. Performance decision criteria consist of the Unconfined Compressive Strength (UCS) and slake durability test results, observation of penetration ability, and comparison of the findings. The three chemicals used were acrylate, colloidal silica, and polyurethane. Test specimens were prepared with two different sand gradations and two different initial moisture contents, which were compacted to the same constant density. Cylindrical test specimens were injected using a constant and predetermined injection pressure. Injected specimens were moist-, air- and wet-cured for 28 days. Thereafter, the specimens were tested and the stress-strain relationships were developed. Slake durability tests were conducted to characterize the durability of chemically grouted sands subjected to wetting-drying cycles. The results of this study showed that initial grain size and fine content of the soil influenced the resultant strength for acrylate and colloidal silica grouting materials. On the other hand, initial moisture content of soil was solely effective on UCS of acrylate grouted sand. This study found that the effect of wetting-drying cycles on durability was minimum for the polyurethane grouted sands. It may be concluded that use of polyurethane in medium sands and use of acrylate in fine sands can be more effective than the use of acrylate, and colloidal silica for medium sands and the use of polyurethane, and colloidal silica for fine sands --Abstract, page iii