Investigation of Subgrade Stabilization Life-Extending Benefits in Flexible Pavements Using a Non-Linear Mechanistic-Empirical Analysis

Abstract

This paper investigates the effect of subgrade soil stabilization on the performance and life extension of flexible pavements. Several variables affecting soil stabilization were considered, including subgrade soil type (CL or CH), additive type and content (3, 6, and 9% of hydrated lime, 5, 10, and 15% of class C fly ash (CFA), and 5, 10, and 15% of cement kiln dust (CKD)), three stabilization thicknesses (15, 30, and 45 cm), and four pavement sections with varying thicknesses. The effects of these variables were investigated using four different damage mechanisms, including the fatigue life of the asphalt concrete (AC) and stabilized subgrade layers, the crushing life of the stabilized subgrade soil, and the rutting life of the pavement, using a non-linear mechanistic-empirical methodology. The results suggest that the optimum percentage that maximizes the pavement life occurs at 3% of lime for subgrade soil type CL, 6% of lime for subgrade type CH, and 15% of CFA and CKD for both subgrade soil types. The maximum pavement life increase occurred in the section with the lowest thickness and the highest stabilization thickness, which was 1890% for 3% of lime in the CL subgrade and 568% for 6% of lime in the CH subgrade. The maximum increase in the pavement life of subgrade stabilization with 15% of CFA was 2048% in a CL subgrade, and 397% in a CH subgrade, and life extension due to subgrade stabilization with 15% of CKD was 2323% in a CL subgrade and 797% in a CH subgrade.

Stabilization of Pavement Subgrade Clay Soil Using Sugarcane Ash and Lime

“…The potential use of natural fibers in construction applications like compacted clay bricks were investigated by Alavéz-Ramírez et al [15]. In these cases, [16][17][18], the natural fibers act as a mechanical stabilizer by adding more interlocking between the soil particles, which in turn increases the strength of the soil containing these fibers. In this process, the natural fiber yarns are randomly distributed throughout the weak soil prior to compaction and the subsequent casting of the adobe bricks.…”

“…The estimated improvement in pavement life for lime, fly ash, and fiber stabilization of subgrade soil increased by 6.49, 4.37, and 3.26 times, respectively. Ghanizadeh et al [16] investigated the effect of subgrade soil stabilization on the performance and life extension of flexible pavements. The results suggest that the optimum percentage of maximum pavement life are 3% lime for subgrade soil type CL, 6% lime for subgrade type CH, and 15% CFA and CKD for both subgrade soil types.…”