Influence of Blending Technique on Surface Free Energy of Modified Asphalt Cement

Abstract

Abstract

The processing technique of modified asphalt cement in the laboratory is adopted by heating the asphalt cement in an oven to the required mixing temperature; then the additive is added and mixed for a target mixing time. It was felt that such technique allows more volatiles to evaporate and required high mixing temperature. In this work, asphalt cement of 44 penetration grade was gained from Dora refinery, south west of Baghdad; the asphalt cement had experienced physical and rheological properties determination. Asphalt cement was then digested with varying percentages of two types of modifiers, Carbon Black (5, 10, and 15%) and Sulfur (3, 5, 7, and 10%), by weight of asphalt. Since the preparation method of modified asphalt cement has a great influence on its quality, two blending techniques have been implemented; the traditional oven heating and stirring, and blending inside the cooking pressure vessel. The surface free energy component of the prepared asphalt cement mixtures was measured using the Wilhelmy plate and sessile drop methods. The aim of this work is to assess how surface free energy characteristics and the blending techniques alter the properties of modified asphalt cement. For comparison, the surface free energy characteristics of the unmodified bitumen were also determined. Based on the result obtained, it was concluded that pressure vessel blending is more appropriate for enhancing the required homogeneity in the blending process. The pressure vessel technique exhibits higher surface free energy of 7.4 and 13.2% for carbon black and sulfur additives respectively with sessile drop method. Wilhelmy plate method shows that the surface free energy is lower by 6.3% and higher by 10% for carbon black and sulfur respectively when the pressure vessel technique was implemented as compared to oven heating technique.

Keywords: Modified asphalt cement, Wilhelmy plate, sessile drop, surface free energy, pressure vessel, blending

Cite this Article

Saad Issa Sarsam, Mustafa Kamal Abdulhussain. Influence of Blending Technique on Surface Free Energy of Modified Asphalt Cement. Trends in Transport Engineering and Applications. 2018; 5(1): 22–31p.