Surface Pavement Solutions for Poor Subgrade Conditions Phase II: Performance Analysis of Test Sections and Implementation Guidelines

摘要

Many regions throughout Florida have shallow layers of organic and plastic soils under existing roads. These roads often exhibit large amount of cracking and distortion in a short period of time. Traditional repairs are often not practical due to high costs and extended construction time. In an effort to develop rehabilitation strategies that could be strictly applied to the surface layer, a pilot test site was selected along the alignment of SR 15/US 98 in northwest Palm Beach county, where severe pavement distresses were observed due to the presence of thick organic layers. PaveTrac MT-1, GlasGrid 8501, PetroGrid 4582, and ARMI were used as promising asphalt reinforcing products in 24 experimental pavement sections, including eight control sections without any reinforcement. A comprehensive field testing and monitoring program involving FWD, rut and ride quality measurements was conducted at the pre-construction, 6-month post-construction, and 18-month post-construction stages. Due to large variability in the subsurface conditions, a statistics-based data analysis protocol was developed for performance evaluation and relative comparisons of the test sections and, in turn, reinforcing products. Post construction data from both 6 months and 18 months demonstrated that stiffness of reinforced sections were significantly higher than the control sections. Procedures were developed to identify and statistically quantify the benefits of derived from the reinforcements only, so that the relative performance of various products could be monitored over time. Based on the field testing data available to date, a framework was developed in the study for the prediction of pavement life, which is essential for conducting a detailed Life Cycle Cost Analysis (LCCA), thus providing FDOT the necessary tools for selecting a site-specific rehabilitation strategy when organic soils are encountered.