Jibon, Md

Base stabilization additives are used to increase the strength and stiffness of road foundations on weak and susceptible soils. The Minnesota Department of Transportation (MnDOT) quantifies the structural contribution of pavement layers by introducing granular equivalency (GE) factors. While numerous additives exist for improving the performance of aggregate base layers, this study focuses on proprietary additives including Base One, Claycrete, EMC SQUARED, PennzSuppress and Roadbond EN1. The laboratory study revealed that EMC SQUARED was the superior stabilizer, with an optimum dosage set 15% higher than the manufacturer recommended dosage (MRD). The long-term performance of proprietary additives was monitored by considering full-scale field implementation with optimum additive dosages obtained from laboratory investigation. Controlled sections without stabilization exhibited higher values in the California Bearing Ratio (CBR) and composite elastic modulus right after construction, while the impact of stabilizers on the increasing strength of the full depth reclaimed (FDR) base was revealed after two years of construction. Falling-Weight Deflectometer (FWD) tests demonstrated a progressive increase in the stiffness of stabilized sections over time, surpassing the control section's stiffness after two years. The economic analysis utilizing Life Cycle Cost Analysis (LCCA) indicated that stabilized sections, particularly those treated with EMC SQUARED, offered lower Equivalent Uniform Annual Cost (EUAC) values across various maintenance scenarios. These findings suggested potential cost savings over a pavement's life cycle with higher GE factors of recycled asphalt pavement base aggregate treated with proprietary additives. The findings will contribute to a comprehensive understanding of the benefits, feasibility, and design considerations associated with using commercial stabilizers in FDR base layers.

The Midwest region of the United States, including Minnesota, has been experiencing an increase in the number of heavy precipitation events. Historical precipitation data confirmed an increasing trend of heavy precipitation in Minnesota in the 21st century. This study focused on assessing the impact of heavy-precipitation events on moisture levels and stiffness of pavement foundation layers at the MnROAD facility. A two-step approach was adopted for predicting changes in saturation and for estimating corresponding resilient modulus values using the resilient modulus prediction equation employed in AASHTOWare Pavement Mechanistic-Empirical (ME) design. PLAXIS 3D, a finite element analysis tool, was used to simulate the movement of moisture within the pavement layer under varying heavy rainfall scenarios. Multiple linear regression models were developed from rainfall simulation data of the PLAXIS 3D model to predict base layer saturation based on rainfall characteristics and hydraulic conductivity of the material. ArcGIS Pro was then used to develop a framework to generate a preliminary vulnerability map showing changes in the resilient modulus of the pavement base layer from rain events. Four regression models were developed and used in ArcGIS Pro to predict changes in resilient modulus for distinct aggregate types under heavy rainfall events, revealing significant reductions in the base layer's resilient modulus. Recycled aggregate (a mix of recycled concrete aggregate and recycled asphalt pavement) emerged as more susceptible, with initial reductions in modulus values higher under heavy rainfall.