A Bitumen-Based Prototype to Predict the Workability of Asphalt Concrete Mixtures

Document Type

Conference Proceeding

Publication Date



Department of Civil, Environmental, and Geospatial Engineering


Having a reliable and repeatable method for measuring the workability of asphalt mixtures for a wide range of asphalt blends is important. The major objective of this paper is to develop a new bitumen-based prototype for the measurement of the workability of different asphalt blends. Correlation and prediction of the mixing temperature with the aid of the developed prototype have been established as a secondary objective of this study. At first, a principle was presented as a basis to develop the workability prototype. The device developed in this study utilized a commercially available motorized Vane Shear Test (VST) apparatus which is mainly used to measure the shear strength of soil. To resemble the aggregate effect while mixing, a specially designed spindle was developed. The VST has been modified to suit the present purpose of the workability test. An accurate torque meter was installed to measure the torque required to rotate the spindle in the blend at a constant revolution. The device was tested with asphalt blends of different ranges of workability. The workabilities of polymer-modified and water-foamed asphalts were evaluated at temperatures of 100, 140 and 180 °C, respectively. It was found that the bitumen-based prototype was able to differentiate the workability in light of the constituents of the studied blends. In addition, the prototype helped in roughly predicting the mixing temperatures of the studied blends based on the concept of Workability Index (WI).

Publication Title

Sustainable Civil Infrastructures