Case Studies in Construction Materials (Dec 2024)
Utilizing olive pomace oil and the extrusion of SBS and PVC to enhance the physical and rheological characteristics of asphalt binder
Abstract
Polymers and bio-oils have recently become increasingly popular for modifying asphalt binders to mitigate pollution, conserve natural resources, and enhance asphalt binders' efficacy by improving their mechanical properties and overall performance. The primary purpose of the current study was to evaluate the efficacy of olive pomace oil (OPO) and polymer blend, created with polyvinyl chloride (PVC) and styrene-butadiene-styrene (SBS) using an extruder, in modifying the properties of asphalt binder. The performance of asphalt binder with the OPO and polymer mix as a novel composition to satisfy performance requirements at all temperatures was investigated for the first time in this research. Initially, OPO was substituted into the base asphalt binder at doses of 3 %, 6 %, and 9 % relative to the asphalt binder weight. Based on the rheological (rotational viscosity (RV), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), and linear amplitude sweep (LAS)) and physical tests (penetration, softening point, ductility), utilizing OPO alone in asphalt binder to improve the intermediate and low temperature performance but diminished the high temperature performance. Thus, a polymer blend with 50 % PVC and 50 % SBS was extruded to alter the asphalt binder's high temperature properties. Subsequently, 5 % of the resultant polymer blend was mixed with the specimen containing 6 % OPO, and the rheological and physical tests were performed again on the specimens produced using the modified composition. Based on the findings, adding the polymer blend to the bio-binder raised the binder's softening point and viscosity and lowered the penetration values. Despite the raised shear strength, the polymer blend-containing specimens did not face any operational challenges related to transportation or pumping. According to the rheological tests, incorporating a 5 % polymer blend in the bio-binder promoted the withstand to permanent deformation at elevated temperatures such that the upper limit of the bio-binder's performance grade was increased by 4 degrees (PG 52 was converted to PG 76). Asphalt binder modification with bio-oil and the proposed polymer blend led to a more flexible sample at low temperatures. By reducing the creep stiffness and raising the creep rate of the lower limit, the base asphalt binder's performance grade was improved by two degrees (PG 64–16 was converted to PG 76–28). Overall, the asphalt binders containing polymer blends were more vulnerable to fatigue cracking at intermediate temperatures than the bio-oil-containing specimens, yet all the modified specimens had superior fatigue life than the base asphalt binder.
