Rheological and Chemical Evolution of HMA and WMA Binders Based on Ageing Kinetics.

Ao Huang,Haoliang Huang,Virginie Mouillet,Tingwei Cao,Gang Liu,Saannibe Ciryle Somé

doi:10.3390/ma15020679

Abstract

It is fundamental to predict or estimate the rheological behavioural evolutions of binders and mixture to ensure a durability service life of the whole infrastructure. This study compared the long-term ageing kinetics of hot mix asphalt (HMA) and warm mix asphalt (WMA) produced with the same base bitumen. The difference in the component was that the WMA contained 1% of Cecabase warm agent and 5.5% of water by the weight of bitumen, to obtain a large expansion ratio (47 times). Rolling thin-film oven test (RTFOT) and pressure ageing vessel (PAV) laboratory ageing were carried out on the binder with or without the warm agent. The oven ageing procedure was conducted on the loose HMA and WMA mixtures for 0, 3, 6, and 9 days. Research results indicated that the dual effect of the studied warm agent and the foaming water sharply decreased the viscosity of the binder at a high temperature. Compared with the HMA, the warm agent improved the ageing resistance of the asphalt binder. However, higher content, such as 5.5 wt.%, of foaming water deteriorated viscosity due to a thinner bitumen film, which was more susceptible to oxidation. Therefore, less than 2 wt.% of warm agent and foaming water was recommended in the foamed WMA preparation.

Highlights

Warm mix asphalt has a paving temperature of 100–140 ◦ C, lower by 20–40 ◦ C than that of traditional hot mix asphalt (HMA) [1]
This study addresses the long-term ageing kinetic comparison of HMA and warm mix asphalt (WMA)
The warm agent reduced the viscosity of bitumen and its shear-thinning behaviour

Summary

Introduction

Warm mix asphalt has a paving temperature of 100–140 ◦ C, lower by 20–40 ◦ C than that of traditional hot mix asphalt (HMA) [1]. There are three main methods to produce WMA by using (i) organic additives, (ii) chemical additives, and (iii) foaming techniques [4]. Wax or fatty amides are usually used as organic additives to reduce the viscosity of asphalt binder [5]. Chemical additives are usually a combination of emulsifiers or surfactants to help asphalt binder covers aggregate at a lower temperature [6]. The addition of water into the hot bitumen causes steam to entrap and generates a large volume of foam, which temporarily increases the volume of the asphalt binder and reduces mix viscosity [4]

Methods

Results

Conclusion