Project Status: Completed

OVERVIEW


As part of Main Roads efforts for continuous improvement, industry professionals have reviewed the current Main Roads practices for contracting work. In response to issues raised, WARRIP launched an investigation to determine what could be done to improve WA practices. Comparisons to approaches taken by other state road authorities helped to reveal some potential solutions and where further study would be beneficial.

PROJECT SUMMARY


Due to the forecast high capital investment by Main Roads WA in construction of new heavy-duty pavements, WARRIP reviewed current pavement engineering practices for large-scale/complex road projects, actively seeking input from both the design and construction industry.

APPROACH

  • Workshop with contractors and pavement designers to identify issues regarding contracting forms and requirements, project scoping documents (SWTC), design guides, pavement materials and other relevant issues
  • Review of major project pavement types and construction specifications used across Australia
  • Review of alternative pavement material technologies identified in workshops and the current use of these materials nationally

CONTRACTORS AND PAVEMENT DESIGNERS WORKSHOP

These workshops highlighted that open discussion and background information improve collaboration, which could be done via various knowledge transfer activities. Contractors are also looking for different forms of contract that reallocate risk, enabling more innovative solutions. After further analysis, WARRIP identified the primary issues to be investigated were:

  • What pavements are permitted and used?
  • How are they are designed?
  • What warranty/defects liability processes are appropriate?

REVIEW OF HEAVY-DUTY PAVEMENT TYPES ACROSS AUSTRALIA

Pavement TypeWANSWQLDVICSA
Full depth
asphalt
Commonly
used
Commonly
used
Commonly
used
Commonly
used
Commonly
used
Deep strength asphaltNot used Commonly
used
Selectively used, previously most common type
>10 years ago
Commonly
used
Rarely used,
previously common type >8 years ago
Thin asphalt on granularCommonly
used
Not permitted as
a heavy-duty
pavement type
Not permitted as
a heavy-duty
pavement type
Not permitted as
a heavy-duty
pavement type
Not permitted as
a heavy-duty
pavement type
Thick asphalt over lean mix concrete (composite pavement)Not usedCommonly
used
Rarely usedNot usedNot used
Hydrated cement –treated crushed rock base (HCTCRB)Selectively used if prerequisites satisfiedNot usedNot usedNot usedNot used
Concrete pavements – PCP, CRCP, JCRP, SFRCLimited useCommonly usedSelectively used, particularly in tunnels and buswaysRarely usedRarely used, but first major use underway
Spray seal on granularCommonly used on rural highways; not permitted on urban projectsCommonly used on rural highways; not permitted on urban projectsCommonly used on rural highways; not permitted on urban projectsCommonly used on rural highways; not permitted on urban projectsCommonly used on rural highways; not permitted on urban projects

EMERGING TECHNOLOGIES AND FUTURE INNOVATIONS

Emerging technologies and future innovations cited during the workshops included:

  • EME2 Asphalt (see WARRIP 2016-001)
  • Increased Reclaimed Asphalt Pavement(RAP) Utilisation (see WARRIP 2017-002)
  • Crumb Rubber Asphalt (see WARRIP 2016-012)
  • Stone Mastic Asphalt (SMA) (see WARRIP 2016-002)
  • Performance Based Specifications for Road Construction Materials
  • Foam Bitumen Stabilisation
  • Potential Use of Nanotechnology (see WARRIP 2018-005) As indicated, some of these emerging technologies were or are currently under investigation by WARRIP.