Detecting the influence of polymeric additives on surface free energy of aged asphalt cement
Saad Issa Sarsam
Physicochemical surface characteristics of asphalt binder material can be well represented by surface free energy (SFE) which is a useful tool for the selection of the moisture-resistant constituent material. Implementation of polymeric additives can reserve or even improve the quality of aged asphalt binder. In the present investigation, an attempt has been made to implement polymeric additives such as crumb rubber (CR) and Low-Density Polyethylene (LDP) for recycling the aged binder of 40-50 penetration grade. The influence of additives was assessed with the aid of surface free energy determination. Sessile drop and Wilhelmy plate techniques have been implemented. It was observed that both additives exhibit higher contact angle and surface free energy when sessile drop technique is implemented regardless of the additive content. However, the contact angle decreases after implementation of additives when Wilhelmy plate technique was used. The SFE increases by (110, 392, and 431) % and (6.9, 40.7, and 66) with the addition of (0.5, 1.0, and 1.5) % of polyethylene when Sessile drop and Wilhelmly plate methods was used respectively. The SFE increases by (243.6, 351.3, and 131.2) % and decreases by (6.7, 18.1, and 51) with the addition of (0.5, 1.0, and 1.5) % of crumb rubber when Sessile drop and Wilhelmly plate methods was used respectively.