Improved Testing Setup for Real-Time Monitoring of PMBs During Manufacturing and Rotational Viscosity Measurements

Abstract

Polymer modified binders (PMBs) are a practical solution to design asphalt mixtures with superior performance. Although these polymers often improve bitumen properties to some extent, their final performance are linked to the accurate control of the properties during manufacturing and storage. However, some of the common procedures used to characterise neat bitumen are not suitable with these binders making their characterisation challenging. This study presents a novel laboratory procedure to produce SBS-MB through a real-time monitoring of the rotational viscosity, as well as an attempt to understand the suitability of current testing geometries to measure viscosity of such a complex bituminous binder. The proposed innovation lies in the adoption of a Dual Helical Ribbon (DHR), as a novel mixing/measuring device for rotational viscometers. The laboratory tests were undertaken by using the DHR and a standard coaxial cylinder configuration with a spindle geometry (SC27) as a control to record eventual differences in viscosity measurements of PMBs. As a result, the real-time monitoring procedure improved the governing of the modifications process, furthermore, it was proven that when blends with high polymer content and no cross linker are tested, the conventional coaxial cylinder setup for rotational viscosity measurements might not be adequate and spindle geometries should be replaced with the DHR.