Strength and Cracking Potential Relationships in Cementitiously Stabilized Pavement Layers

Chemical stabilization of marginal materials with calcium-based agents is a sustainable means to improve the engineering properties of multi-layer structures. In the stabilization process, hydration reactions form cementitious compounds creating strong interparticle bonds, which in turn lead to a more efficient load distribution capacity of the pavement foundations. Mixture design anomalies give rise to the continuous consumption of water in exothermic hydration reactions, which results in the volumetric instability and cracking of the cementitiously stabilized layers. Such cracks can potentially propagate to other layers and jeopardize the longevity and performance of the pavement structures. Therefore, it deems necessary to characterize the shrinkage cracking potential of cement-treated layers properly. Traditionally, a limiting threshold of the unconfined compressive strength test during the mixture design is defined to predict the cracking behavior of the stabilized layers. This study, however, explores practical techniques to measure the shrinkage strain in cement-treated granular materials with specific thermal cycle provisions for virgin aggregates, recycled materials, and full depth reclamation (FDR) mixtures. The main focus of this research was to study the impact of aggregate type and cement dosage on the shrinkage strain of prismatic specimens in the laboratory and to develop relationships between the volumetric strain, unconfined compressive strength, and indirect diametrical tensile strength of cement-treated marginal materials. To accomplish these objectives, a laboratory program was developed considering four different aggregate sources and three increasing levels of stabilizer dosage. The post-processed laboratory results showed the inconsistency of predictions of cracking potential using the traditional strength tests. The deviation from the expected norms was more pronounced for the FDR materials with potential contaminations of the mixes with plastic subgrade soils during the milling process. The outcome of this research can provide valuable insight into the laboratory mixture design of pavement foundations using virgin, recycled, and reclaimed materials treated with cementitious stabilizers.