Experimental Assessment of Mineral Filler on the Volumetric Properties and Mechanical Performance of HMA Mixtures

Hanaa Khaleel Alwan Al-Bayati,Abimbola Grace Oyeyi,Susan L Tighe

doi:10.28991/cej-2020-03091619

Hanaa Khaleel Alwan Al-Bayati, Abimbola Grace Oyeyi + Show 1 more

Open Access

https://doi.org/10.28991/cej-2020-03091619

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Abstract

This research is conducted to evaluate the influence of mineral filler on the volumetric properties, mechanical and field performance of Hot Mix Asphalt (HMA). Two mineral filler types, namely, Hydrated Lime (HL) and Dust Plant (DPt) were used. Three filler proportions were utilized greater than 1% which represents the most applicable percentage, especially for HL, used by the Ministry of Transportation Ontario (MTO). The effect of filler on various volumetric properties including Voids In Mineral Aggregates (VMA), Voids Filled With Asphalt (VFA), dust to binder ratio (Dp) is examined. Mechanical and predicted field performance of HMA to the best filler proportion that meets all the MTO limitations is also investigated. The obtained results indicated that the Optimum Asphalt Content (OAC), VMA, and VFA decrease as the filler content is increased. HMA mixtures that includes DPt filler had the higher values of VMA, VFA, and OAC compared to the hydrated lime. The addition of filler with 2.5% percentage is very successful for both filler types due to satisfying all MTO requirements for volumetric properties of HMA. Based on MTO specifications, the addition of 2.0% filler seems to be unsuccessful for both filler types due to lowering the Dp ratio. Mix design with 3.0% filler was also unsuccessful because of the lower value of OAC meaning that the mix is dry and there is insufficient asphalt binder to coat the aggregate particles. Besides, filler type has a significant effect on the mechanical properties of the HMA mixtures. As a filler in HMA mixtures, the utilization of HL as a portion of 2.5 % leads to a significant improvement in mixture resistance to water and freezing and thawing. The mixtures that included HL have a higher cracking resistance, greater stiffness, and a higher fracture stress than the mixtures that included DPt. Furthermore, predicted field performance indicated better outcomes for mixes with HL compared to DPt mixes. Doi: 10.28991/cej-2020-03091619 Full Text: PDF

Highlights

For the construction of road pavements throughout the world, one of the essential materials required is asphalt mixture [1]
It is noteworthy that a significant decrease in the optimum asphalt binder content is observed when filler content is increased from 2.5% to 3% for both filler types, which is correspondence with Huang's conclusion [11]
The results demonstrated that the mixtures that included Hydrated Lime (HL) at different percentages have a lower Optimum Asphalt Content (OAC) than the mixtures that included a Dust Plant (DPt) filler type

Summary

Introduction

For the construction of road pavements throughout the world, one of the essential materials required is asphalt mixture [1]. It is widely known that asphalt mixture is a heterogeneous material that essentially consists of different constituents including asphalt, natural or recycled aggregate, fillers, and air voids. Asphalt mixture is mainly composed of approximately 95% aggregate and 5% asphalt binder materials. The physical properties of both coarse and fine aggregates have a considerable influence on the asphalt pavement performance [3]. The design of asphalt mixtures can be described as a complicated process that requires very accurate proportions of aggregate and asphalt binder in order to achieve specific requirements of volumetric and mechanical properties [4]

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