Title: Lithium Salts as Set Accelerators for Refractory Concretes: Correlation of Chemical Properties With Setting Times
Author(s): Thomas Novinson and John Crahan
Publication: Materials Journal
Appears on pages(s): 12-16
Keywords: accelerating agents; chemical analysis; concretes; lithium; pH; setting (hardening); Materials Research
Lithium salts have been reported as set accelerators of high-alumina (80 to 90 percent) concretes and mortars. However, it has been determined that the lithium salts also accelerate the setting of medium-alumina (40 percent) concretes containing considerable silica. The reaction rates of the accelerated setting are related to the pH of the lithium salt in the mixing water, the concentration of the lithium salt, and the type of anion in the lithium salt. Proper selection of the lithium salt and the concentration can lead to quick-setting concretes without loss in quality. The nonhalide lithium salts may have an advantage over calcium chloride and other halide-set accelerators that have been found to be highly corrosive to steel reinforcement in concrete. Since the lithium salts act as catalysts and cause hydration of the cement, components without entering the stoichiometry of the reactions, very small amounts of the salts can be used to accelerate the concrete setting reaction.