Accelerated Moisture Conditioning Process of Lime-Stabilized Clays

Abstract

Lime stabilization is a common procedure currently used in road construction. This technique is particularly attractive for improving the subgrade material for low-volume unpaved or low-cost paved roads. Selection of the proper concentration of lime for stabilization of clays is primarily based on achieving a target pH value. A number of parameters—such as the interaction between the mineralogy of the clay materials and the additives in the presence or absence of moisture, construction methods, and curing processes—significantly affect the performance of stabilized clays. If the selected concentration of additives is not adequate to ensure shortand long-term strength and durability, the stabilization will be ineffective, and pavement rehabilitations, requiring costly repairs and road closures, will be necessary. Many state highway agencies supplement this design process with other tests to ensure that proper strength, stiffness, and durability can be achieved. The most common parameter considered for this purpose is the unconfined compressive strength of laboratory-prepared specimens that are cured for several days and subjected to capillary moisture conditioning for several additional days. This procedure is perceived as time-consuming to implement. To establish whether the stabilization method is effective in field construction projects, this paper addresses some shortcomings in the current protocols. Several accelerated testing methods that could potentially minimize the time required for soil specimen preparation, curing, conditioning, and testing to complete the stabilizer design process are evaluated. From this study, the most appropriate method was found to be backpressure saturation.