PUBLIC LECTURE: The benefit of Lime Stabilisation of Subgrade and Foam Bitumen Stabilisation of Base

Mr. Jothi Ramanujam
(Director (Pavements Rehabilitation), Pavements Rehabilitation Section, Department of Transport and Main Roads,Queensland, Australia)

Mr. Peter Evans
[Deputy Chief Engineer (Pavements, Materials & Geotechnical), Department of Transport and Main Roads, Queensland, Australia]

Presenters:

Mr. JOTHI RAMANUJAM (RAMA)

Rama has 42 years of experience in road construction, design and rehabilitation. He has been with Queensland Main Roads Department, Australia for the past 26 years. He has also worked in a number of countries including Sri-Lanka, Nigeria, UK, Abu-Dhabi (UAE) and Brunei. He holds a Masters Degree in Construction Engineering from the University of Leeds, UK.

Rama currently holds the position of Director (Pavements Rehabilitation) of the Department of transport and Main Roads in Queensland, Australia. He has been involved in a number of major
pavement investigation works, pavement performance studies, R&D works on insitu stabilization including pioneering work on Foam Bitumen Stabilisation and Hot In-Place Asphalt Recycling. Rama has
written a number of reports and technical papers for both local and international conferences such as Transport Research Board Conference in Washington, USA. Rama compiled and published the
Queensland Transport Pavement Rehabilitation Manual and won an Excellence Award from the Department Excellence Award Scheme in 1992. He and his team has reviewed and republished the Pavement Rehabilitation Manual in April 2012. This manual is now available in the TMR web site for reference.

Mr. Peter Evans

Peter is currently the Deputy Chief Engineer (Pavements, Materials and Geotechnical) of the Department of Transport and Main Roads in Queensland, Australia. where he heads up a team of 4 Directors and approximately 90 staff providing specialist advice and testing services to the 12 regions throughout Queensland. Before taking on this role in February 2011, Peter had served since 1982 in different roles in Main Roads and Transport and Main Roads throughout Queensland, and was Regional Director of the South West region based in Roma.

Abstract:

Through technical advice and project-linked training, Engineering & Technology Branch of the Transport and Main Roads (TMR) Department of Queensland, Australia has been helping to deliver more durable pavements for Queensland. Significant improvements in the performance of roads have been obtained through either lime stabilisation of the subgrade or foam bitumen stabilisation of the base or through the combination of lime stabilised subgrade and foam bitumen stabilised base.

Subgrade stabilisation can be defined as a means of enhancing soil strength and stiffness properties by adding a hydraulic binder such as lime. Correctly applied, stabilisation will also decrease the subgrade’s water sensitivity and volume changes during wet/dry cycles Lime stabilisation causes a significant improvement in the soil structure by reducing plasticity and providing pozzolanic strength gain. Investigations have shown a significant level of increase in long term strength in lime stabilised subgrades in TMR projects. It has been shown that TMR’s established testing protocol and mix design procedures lead to optimum amount of lime to stabilise the subgrade.

TMR has also been developing the foamed bitumen stabilisation technique for pavement base materials, in consultation with the Australian pavement stabilisation industry. The technique has
provided a more flexible and fatigue resistant stabilisation treatment suitable for Queensland conditions. Several projects have been constructed using this technique.

This technique has become more widely accepted having stabilised more than 500 km of road pavement. The design, construction and maintenance techniques are continuously being developed in
light of the increased data available. Achievements to date include improved mix design procedures, detailed Technical Note 44, standard specification and technology transfer. Technology transfer not only includes in-house training sessions but project linked field training.

A number of flood affected roads have been recently rehabilitated using the combination of these individual techniques of lime stabilisation of the subgrade and foam bitumen stabilisation of the
existing pavement. These combinations of the techniques have introduced more flood resilient, durable, cost-effective roads for Queensland.

The aim of this Paper and presentation is to highlight the benefits of these treatments.