Compressive Strength of Reclaimed Base Material Treated with Asphalt Emulsion and Portland Cement

Full-depth reclamation (FDR) in conjunction with stabilization is becoming an increasingly popular method of flexible pavement reconstruction. Unfortunately, however, not all FDR projects are considered successful. While on most projects problems can be prevented through careful materials sampling and testing and construction supervision, they are often exacerbated by adverse environmental conditions. This research was derived from an FDR project in which a newly constructed emulsion-treated base (ETB) layer exhibited significant early-age rutting due to low temperatures and high water contents at the site. In the context of this project, the objective of this research was to evaluate the potentially synergistic interaction between asphalt emulsion and portland cement applied to the base material. To that end, compressive strengths were measured over time for laboratory specimens treated with emulsion only, emulsion and cement, and cement only. The data show that the addition of cement to ETB generates immediate and substantial increases in strength with continued strength gains over time and that higher amounts of cement provide greater strength. The data also clearly show that, for the conditions specified in this experiment, the interaction between emulsion and cement was not synergistic; instead, specimens that contained emulsion had an average strength that was substantially lower than that of specimens that did not contain emulsion. Finally, the data show that, even after extended periods, ETB materials from which water cannot evaporate will not gain strength. These results emphasize the importance of choosing stabilizers that will achieve the desired material improvements even in adverse environmental conditions.