A Sustainability Perspective for Unbound Reclaimed Asphalt Pavement (RAP) as a Pavement Base Material

Abstract

The present study aims to investigate reclaimed asphalt pavement (RAP) materials for utilization for a pavement base layer material with the goal towards increasing the reutilization of materials and the movement towards increased pavement sustainability. Reduced cost for materials and transportation of materials, overall environmental benefits and many other advantages have led to increased interests in utilizing RAP in pavements including as base materials for highway/roadway construction projects. The potential advantages of utilizing RAP as an unbound base material are known; however, its overall application is still limited partially due to the lack of systematic evaluation studies for the parameterization of RAPs mechanical behavior in pavement design. With this in mind, the current investigation focuses on the resilient modulus (Mr) properties of RAP aggregates in terms of a material’s elastic response. Experimental data from tri-axial stress tests on specimens consisting of RAP, aggregates and a mixture of both materials are investigated. A number of constitutive models for the description of mechanical behavior of RAP materials are investigated. The required procedures for determining the constitutive constants of the constitutive models is outlined for the aforementioned materials. A comparative analysis is applied, and the related results are evaluated. The main conclusion is that RAP materials can be utilized as a base material in the framework of pavement sustainability, as its behavior under loading conditions are similar to virgin aggregate (VA) materials and can be simulated by using appropriate constitutive models for pavement design processes.

Pullout Behaviour of Geogrids Embedded in a Recycled Construction and Demolition Material. Effects of Specimen Size and Displacement Rate

“…This suggests that the reliance on natural aggregates in geotechnical applications is high and the inclusion of recycled aggregates can contribute significantly to preserve the environment. In view of the above, several studies have recently been conducted to evaluate the feasibility of using recycled C&D wastes in diverse geotechnical applications, such as ground improvement works [8,9], pipe bedding and backfilling [10,11], construction of paved and unpaved roads [12][13][14][15][16][17][18] and backfilling of geosynthetic-reinforced structures [19][20][21][22].…”

“…Most of the studies carried out on recycled aggregates from C&D waste are related to recycled concrete aggregates [9,10,14,23] or reclaimed asphalt pavement materials [16,17]. However, particularly in Southern European Countries, C&D wastes sent out at the recycling plants are mainly mixed wastes (comprising concrete, mortars, stones, ceramics,).…”

Improving the Environmental Sustainability of Low Noise Pavements: Comparative Life Cycle Assessment of Reclaimed Asphalt and Crumb Rubber Based Warm Mix Technologies

“…Reclaimed asphalt pavement (RAP) is the removed and reprocessed pavement material typically generated from milling operations in rehabilitation projects [10]. Nowadays reuse of RAP is a common practice in many European countries [11][12][13], representing the most used material for replacing virgin raw materials (aggregates and bitumen) in asphalt mixtures [14]. However, the introduction of RAP to conventional hot mix asphalt (HMA) requires additional heating energy to achieve adequate levels of bitumen viscosity [15], with a consequent increase of air emissions during the production stage.…”

Fatigue Properties of Cold-Recycled Emulsified Asphalt Mixtures Fabricated by Different Compaction Methods

“…The recycling of reclaimed asphalt pavement (RAP) has been developed worldwide because of its remarkable economic and environmental benefits [1,2]. As a valuable way to recycling RAP, cold-recycled emulsified asphalt mixtures (CEAMs) have been extensively employed in highway maintenance projects in China because of their properties of energy efficiency, environment protection, and convenient construction [3][4][5].…”