Performance Comparison of Break and Seat and Rubblization Rehabilitation Techniques for Reflection-Crack Mitigation: Case Study in Louisiana

Abstract

Hot mix asphalt (HMA) overlays are constructed on Portland cement concrete (PCC) pavements to improve long-term performance. A significant disadvantage of using HMA overlays on PCC pavements is the development of reflection cracks. Reflection cracks are influenced by traffic loads and periodic temperature changes. The objective of the study was to compare field performance of two slab-fracturing (i.e., break and seat, and rubblization) techniques commonly used in Louisiana, U.S. Four PCC pavement rehabilitation projects with at least one slab-fracturing technique and a corresponding control section were evaluated. Field structural capacity and performance data were collected and analyzed to determine the effect of each reflection-crack mitigation technique on performance. Resilient modulus (M_r) of the existing subgrade was found to significantly influence the structural and functional performance of the pavement sections evaluated. Pavement sections with weaker subgrades were shown to be not suitable for slab-fracturing rehabilitation techniques. For the four field projects evaluated, rubblized test sections showed higher cracking resistance than the control sections. The break and seat technique did not consistently improve or reduce the crack resistance of pavement sections compared with their corresponding control sections because of variations in subgrade M_r values. Sections with smaller sized (i.e., 6 in. break pattern and rubblized particles) fractured particles exhibited higher cracking resistance. Rubblized and selected break and seat sections for the field projects evaluated exhibited lower overall performance compared with their corresponding control sections, which is attributed to other underlying subsurface conditions. Additional study is required to continuously monitor the pavement sections.