Use of Bitumen Rubber Modified (A-Rel) Hot Mix Asphalt Overlay as Pavement Preservation Treatment With Limited Pre-Treatment

Description

Use of Bitumen Rubber Modified (A-Rel) Hot Mix Asphalt Overlay as Pavement Preservation Treatment With Limited Pre-Treatment

Mk Hofmeyr,  Jl Van Heerden, H Marais

ABSTRACT: During 2013 a Bitumen Rubber Asphalt (BRA) surface overlay was constructed as a pavement preservation measure over a distressed asphalt surface, without repairing any of the varying type, degree and extent of surface cracks present on the existing asphalt surface.

The focus of this paper is the assessment and documentation of the performance measured over the first five years of the Bitumen Rubber Asphalt (BRA) surface overlay, constructed as a pavement preservation measure over the distressed asphalt surface.

The deterioration of the South African road network is primarily caused by limited timeous pavement preservation applied to the ageing road infrastructure, due to numerous reasons. Hot mix asphalt surface overlays provide a like-new surface, prolong the life of a distressed surface and cause limited disruption to traffic during construction compared to other surface treatments.

Increased durability, improved flexibility and a greater resistance to reflective cracking properties of Bitumen Rubber Asphalt (BRA) make it an ideal preservation option. Although the performance of BRA is well documented, there is limited guidance on what degree and extent of unsealed surface cracking can successfully be overlaid without cracks reflecting through the newly constructed asphalt surfacing overlay.

As part of a resurfacing project for the Western Cape Government, four experimental sections were selected and overlaid with a Bitumen Rubber Asphalt (BRA) without repairing the varying type, degree and extent of surface cracks. These sections are subjected to a Long-Term Pavement Performance (LTPP) program to monitor crack propagation over time.

This paper aims to demonstrate the effectiveness of a BRA surface overlay, constructed as pavement preservation, without any preparation to the underlying distressed asphalt surface.

KEYWORDS: bitumen-rubber properties, reflection cracking, overlay design