Testing and Microcracking Assessment of Cement-Treated Full-Depth Reclamation

Abstract

Full-depth reclamation (FDR) has gained increasing recognition as an efficient and cost-effective pavement rehabilitation method by recycling up to 100% of existing materials on-site, with Portland cement-stabilized FDR (FDR–PC) providing enhanced structural integrity. A comprehensive understanding of the mechanical properties of FDR–PC is essential to optimize its design and improve implementation efficiency. This study investigated the mechanical characteristics of FDR–PC, the interrelationships among various tests, and assessed the use of microcracking on constructed accelerated pavement test sections. Tests conducted included compressive strength (CS), flexural strength, elastic modulus, and shrinkage behavior in the laboratory, and deflection testing using a falling weight deflectometer. Four constructed FDR–PC pavement sections, including 3.25% and 5.5% cement content (by weight), both with and without induced microcracking, were built to study the shrinkage concerns observed during practice associated with FDR–PC. In addition, the influence of the microcracking technique was evaluated. The findings include: (1) a correlation factor of 1.46 to account for specimen-size effects in FDR–PC CS testing; (2) a slower loading rate than that specified in ASTM C469 may be more appropriate for characterizing FDR–PC; (3) the American Concrete Institute-based modulus predictions tend to overestimate FDR–PC stiffness; (4) the American Association of State Highway and Transportation Officials model provided the most accurate 7-day modulus of rupture (MoR) estimates; (5) length change test results were influenced by density and cement content; (6) strong correlations were observed among all evaluated mechanical properties; and (7) microcracked mixtures gained stiffness over time, with greater initial reduction in the lower-stiffness FDR–PC and significant stiffness recovery in the high-stiffness FDR–PC.