Laboratory characterisation of recycled asphalt pavement as a base layer

Abstract

Asphalt rehabilitation projects produce about 100 million tons of recycled asphalt pavement (RAP) per year from millings, presenting a major solid waste concern. Literature indicates that RAP has a structural value as a pavement layer. However, limited research exists to quantify its structural capacity with fundamental engineering properties, especially for high RAP contents. Properties such as the resilient modulus (M _R) of unbound layers are needed in the mechanistic–empirical pavement design guide. This paper investigates the behaviour of base layer mixture containing RAP at different quantities using resilient modulus (M _R) from laboratory testing. RAP from millings was blended in varied quantities with local aggregates. Densities also varied among test specimens. Resilient modulus tests showed that as RAP content increased, M _R increased. Results also showed a strong positive correlation between M _R and density. Conclusions indicate RAP has a potential to be used in high percentages in pavement base layer applications. Doing so may help alleviate a growing environmental problem while providing a strong pavement foundation.

Keywords:

• RAP
• resilient modulus
• pavement
• base
• layer

Acknowledgements

The authors would like to acknowledge the Mn/DOT for supporting this research and for providing all the resilient modulus testing data. Also would like to acknowledge Mr John Zollars and Dr Shongtao Dai of Mn/DOT for their support.

Notes

^1. [email protected]

^2. [email protected]

Additional information

Notes on contributors

Tahsina Binte Alam

1. 1. [email protected]

Scott A. Schram

2. 2. [email protected]