by The National Asset Centre of Excellence (NACOE)
The National Asset Centre of Excellence (NACOE) has been investigating Intelligent Compaction (IC) technology and the role it can play in constructing roads in Queensland. This research focuses on the use of IC to improve the construction quality of both earthwork embankment and pavement construction, and activities have been undertaken to accelerate market acceptance in Australia.
What role does the quality of compaction in road construction have on delivering a long-lasting, high performing pavement? The industry knows just how vital the compaction process is to achieve the best outcome. Many local and state governments are becoming increasingly concerned with costly repairs and maintenance that can occur later down the road due to poorly compacted pavements.
Intelligent Compaction technology has the potential to significantly reduce construction and maintenance costs by optimising the compaction process through improved uniformity and consistency of materials. It brings with it real-time feedback and monitors to assist the roller operator, using a system of hardware, software and analysis equipment.
Although Intelligent Compaction technology is quite new to Australia, it has a proven track record overseas, where it was first developed in Europe and has been increasingly used throughout Asia and the United States. As part of the NACOE program, a research project commenced in January 2019 intending to assess the suitability of implementing Intelligent Compaction for quality control in future road construction.
What is Intelligent Compaction technology?
Intelligent Compaction refers to the use of a roller equipped with an integrated measurement system, often using an accelerometer mounted on the roller drum and a precision GPS unit. For the use of asphalt compaction, infrared temperature sensors are also mounted on the roller to track asphalt surface temperature during compaction.
The Intelligent Compaction technology has an on-board computer display which provides the operator with real-time feedback on the stiffness of the compacted materials and the number of roller passes the roller has made.
Intelligent Compaction rollers allow the operator to view plots of the precise location of the roller and continuously determine a measured value of the material stiffness and number of roller passes during the compaction process by maintaining an ongoing record of colour-coded plots.
What are the benefits of using Intelligent Compaction?
Through researching international best practice and field testing the technology in Queensland, Intelligent Compaction is displaying benefits in the following areas:
- Real-time operator feedback enabling continuous placement of material (without delays of traditional test methods)
- Identify weak areas on pre-mapping of underlying layers
- Optimise rolling pattern (coverage and speeds)
- Allows for 100 per cent of compacted area to be assessed, avoiding under/over compaction of isolated areas
- Capturing and securely storing the compaction process information as permanent georeferenced records
- Improved uniformity of earthworks and pavements, which is expected to lead to significant improvements in service life
- Reduction in greenhouse gas emissions due to more efficient construction practices and reduced maintenance
Intelligent Compaction data management workshop in Queensland
The NACOE research on Intelligent Compaction implementation is led by Dr Jeffrey Lee, who delivered the first-ever two-day Intelligent Compaction Data Management (ICDM) workshop in Queensland in 2019, alongside Dr George Chang.
The first day of the event covered the basics of Intelligent Compaction, which gave participants a hands-on experience of using the Veta software. On the second day, a field demonstration was conducted using a Dynapac smooth drum roller with a Trimble IC retrofit kit at a test strip, where the Intelligent Compaction roller was used to compact a general fill area (60m by 23m) on test strips
using three different moisture contents.
The exercise familiarised participants with Intelligent Compaction technology and demonstrated how to use a test strip to establish a target Intelligent Compaction Measurement Value (ICMV) and roller passes for process control.
Development of first technical specification for Intelligent Compaction in Australia
As part of the NACOE project, the need to draft a technical specification was identified to use on Queensland Department of Transport and Main Roads (TMR) projects to trial the Intelligent Compaction technology.
This led to the development of the first ever project-specific technical specification in Australia PSTS116 Intelligent Compaction – Earthworks and Pavements, which is intended for the use of the compaction of earthworks, unbound and stabilised pavement layers, but excludes asphalt layers and sprayed bituminous seals.
PSTS116 was initially developed to undertake a compaction audit using an Intelligent Compaction roller on the Ipswich Motorway Upgrade: Rocklea to Darra – Stage 1 (R2D) project between March and October 2020. The Intelligent Compaction roller was used to compact embankment fill, subgrade, plant mixed lightly bound material and unbound granular base material.
The use of Intelligent Compaction on this project has assisted TMR to evaluate the benefit of the technology and develop a strategy to implement Intelligent Compaction into TMR’s standard specifications.
To support the implementation of PSTS116 and the wider use of Intelligent Compaction in Australia, NACOE has also funded updates to the international Veta software to allow it to be used in Australia and support GDA 2020.
The Veta software was developed by the Transtec Group in 2012, and is used around the world to interpret and analyse Intelligent Compaction, Paver-Mounted Thermal Profiles (PMTP), Dielectric Profile System (DPS), and future emerging Intelligent Construction Technologies (ICT).
Intelligent Compaction in action
NACOE was pleased to work with the Logan City Council on the Logan Street Pavement Rehabilitation Project, completed in late 2019, the first of its kind in Australia to capture data that allows the council to manage unstable ground in a more efficient way using Intelligent Compaction technology.
The project won the Local Government Managers Australia (Queensland) Excellence Award in 2020 in the collaboration category and included a collaboration of multiple parties: Logan City Council, NACOE and Queensland University of Technology (QUT).
It has generated ideas in the road industry on how local governments can play a leading role in cutting-edge road research and the development of innovative technologies.
NACOE is an initiative of the Queensland Department of Transport and Main Roads and the Australian Road Research Board (ARRB), committed to delivering efficiencies and innovation through road infrastructure related research. For more information, please contact [email protected] or visit nacoe.com.au.