Effects of Reduction in Construction Temperature on Workability of Warm Mix Asphalt Incorporating Rh-wma Additive

Abstract

Conventional Hot Mix Asphalt (HMA) has been the primary material used in pavement in past decades. Recently, compared to conventional HMA, Warm Mix Asphalt (WMA) has shown great potential and offers benefits not given by HMA, since the WMA can be produced at lower temperatures without affecting pavement performance. The WMA technologies allow a significant reduction in construction temperatures of asphalt mixtures through lowering the viscosity of binders. In WMA, different types of additives are added to the binder depending on the technology used and such addition of these materials brings down the viscosity drastically thus reducing the temperature to which the aggregates and binders have to be heated during mixing and compaction. This study was limited to the effects of construction temperature on the workability performance of WMA incorporating RH-WMA additive. Binder namely 80/100 was used for preparation of all asphalt mixtures and RH-WMA used as warm mix asphalt additive. Asphalt mixtures were prepared using crushed granite aggregate for AC14 wearing course and compacted by using Servopac Gyratory Compactor (SGC). The Leeds Workability Method used to determine the workability index. The results show that increase in construction temperature improves the workability of both WMA and HMA. Workability Index (WI) of mixtures incorporating 3% RH-WMA is slightly higher than mixtures incorporating 2% RH-WMA. The increase in WI is more pronounced at higher RH-WMA contents.

New Methodology to Characterize the Workability of Asphaltic Concrete Mixtures Based on Kinematic Compaction Energy

“…Cabrera and Dixon [22] proposed a workability Index (WI) that was based on the correlation between the mixture porosity and the associated compaction energy via a gyratory compactor. Under the same field compaction effort, mixes with a higher WI are more workable [23]. A higher WI is associated with material that is easier to compact in the field.…”