Comparison of hydrated lime, paraffin wax and low-density polyethylene modified bituminous binders: a perspective of adhesion and moisture damage

Abstract

ABSTRACT Adhesion and moisture damage are significant factors in the early failure of pavements. This study examined the adhesion and moisture resistance of three types of binders (40–50, 60–70, and 80–100 pen bitumen) modified with paraffin wax (PW), hydrated lime (HL), and low-density polyethylene (LDPE) at dosages of 1% and 2% by weight of the binder. The Bitumen Bond Strength (BBS) test was performed using the Pneumatic Adhesion Tensile Testing Instrument (PATTI) to measure Pull-Off Tensile Strength (POTS) and determine the type of failure following dry and wet conditioning. Additionally, the mixture was tested for moisture susceptibility using the Rolling Bottle Test (RBT). The RBT results showed that adding LDPE and HL to the control binder increased bitumen coverage, indicating greater resistance to moisture damage. In contrast, adding PW reduced bitumen coverage, indicating higher susceptibility to moisture damage. Based on the BBS test, LDPE and HL-modified bitumen developed greater bond strengths as POTS values increased, while PW-modified bitumen developed decreased bond strengths as POTS values decreased.