Permanent Deformation Behavior under Repeated Load of Recycled Material Stabilized with Bitumen Emulsion

Abstract

Cold in-place recycling (CIR) with bitumen emulsion is a method for enhancing resistance to permanent deformation damages of flexible pavement. The objective of the study was to examine the permanent deformation behavior of a bitumen-stabilized material (BSM) subjected to repeated loads. To achieve this, the aggregate was derived from reclaimed asphalt pavement and reclaimed crushed rock in the ratio of 25:75 mixed with 2% or 3% bitumen in emulsion and 1% Portland cement (of the total aggregate weight). After that, the specimens were subjected to repeated loads following the EN13286-7 method. The results were as follows. At the compressive deviatoric stress level of 550 kPa, All of BSM specimens with 2% and 3% bitumen exhibited the plastic shakedown equilibrium pattern of permanent deformation after 1,000,000 cycles of repeated loads and their permanent strain were less than 0.6%. The results also indicated that once the permanent strain rate decreased to 0.004 microstrain/cycle or lower, the BSM became stable in the plastic shakedown state. The findings in this study may serve as guidelines for designing pavement rehabilitation with BSM to prevent permanent deformation caused by traffic loads.