Mitchell Freeway Resurfacing

Project Background

Main Roads Western Australia (MRWA) commission an annual Asphalt Resurfacing Maintenance Contract under their joint venture with DM Roads. Mitchell Freeway is Perth’s primary transport corridor to the north. For the 2020/2021 maintenance season, Fulton Hogan was awarded a section of Mitchell Freeway northbound from the Shenton Avenue on-ramp. Various sections of this stretch of freeway required the application of a Geotextile Reinforced Seal (GRS) in accordance with MRWA specification 511.

Problem

Pre-existing pavement formations often suffer the typical surficial defects caused by excessive wear, particularly in the case of major freeway structures. Mitchell Freeway is no different. Lateral & longitudinal crack formation is a sign of pavement deterioration that can result from a multitude of causes. MRWA instigate a pre-emptive maintenance program to get on top of these surficial defects before they promote problems deeper in the pavement, thus obviating more onerous and costly restoration activities.

Solution

Global Synthetics ProPave® is a nonwoven paving fabric used primarily in the maintenance and repair of asphalt road surfaces. Nonwoven geotextiles are utilised in a variety of different civil engineering applications but ProPave® is specially needle punched and heat-treated to exhibit optimal bitumen absorption properties, enabling it to form a composite bond within the asphalt structure. Once this occurs, pavement performance is enhanced via the following mechanisms:

• Eliminate water intrusion through the asphalt

• Slow reflective cracking

• Stress absorption and minimisation

• Increased flexibility of the pavement system

• Extended service life

• Reduction in maintenance frequency

Note that ProPave® GRS is also employed within the wearing course for new pavements constructed with materials prone to shrinkage cracking, fatigue cracking, or founded by expansive clay subgrades.

Results

In this case, the Paving Fabric was laid with minimal complications. The contractor learned and quoted the following:

1. Constant tension needed to be applied with the applicator to avoid the development of wrinkles.

2. Sudden track movements should be avoided to prevent overstress of the geotextile.

3. ProPave® outperformed any of the other products previously used in the same application.

ProPave® AS180P paving geotextile was selected by Fulton Hogan given the material conforms to ‘MRWA Standard 511’ and is readily available in large quantities at Global Synthetics large warehouse facility in Perth. Fulton Hogan’s longstanding relationship with Global Synthetics and its familiarity with ‘AS180P’ as a quality product, made for an easy decision.