Evaluating the cost effectiveness of using various types of stabilized base layers in flexible pavements

Abstract

This study was initiated with the aim of determining the cost effectiveness of utilizing various types of stabilizers in the base layer of flexible pavements. Five field sections that were formerly part of a controlled study conducted by Rhode Island Department of Transportation (RIDOT) were evaluated in this study. All field sections contained a 4.5 in. hot mix asphalt (HMA) surface layer and 1 in. granular subbase. Four of the five sections were constructed using stabilized base layers (i.e., calcium chloride (CaCl2), Portland cement, geogrid, and bituminous (asphalt emulsion) stabilized base layers). A control section was constructed using 100% untreated, recycled asphalt pavement (RAP) base layer. All sections were located on Rhode Island Route 165 (between utility poles 304 and 521). Falling weight deflectometer (FWD) tests were conducted on the field sections and the collected deflection data was used to back-calculate the elastic moduli for all layers on each highway segment. AASHTOWare Pavement ME Design simulations were conducted to determine the predicted fatigue and rutting performance of the flexible pavement sections. The results of the Pavement ME design simulations were used in conjunction with the RIDOT Pavement Structural Health Index (PSHI) to determine the total life cycle cost of each pavement section. Based on the results of the study it was determined that stabilization of base layers during full depth reclamation were not cost effective because pavement sections that contained stabilized bases had a higher total life cycle cost than the pavement section that contained an untreated base.