Leah Fisher Chief Executive Officer, AustStab, NSW, Warren Smith Director, Stabilised Pavements of Australia, Somersby, NSW, Australia

Stabilisation provides Flood Recovery a sustainable solution for pavement management

Abstract

As part of the National Disaster Relief and Recovery Arrangements (NDRRA), work was undertaken to reconstruct Queensland's Road Network following disaster events in 2010-2012 and 2013. Pavement stabilisation was utilised in over $1 billion worth of work constructed under this funding.

Sustainable Materials

Pavement stabilisation was utilised for full depth recycling of all layers of suitable existing pavement materials insitu. Stabilisation allowed for poorer quality virgin quarry products to be modified either mechanically, chemically or using a combination of both processes to make them suitable for incorporation into new pavements.

Doing More with Less

A case study example of stabilisation will be presented based on the Queensland environment using cement stabilisation in Townsville. Stabilisation provides an economically, socially and environmentally sound pavement maintenance solution

The market has experienced unprecedented opportunity to trial pavement stabilisation in all levels of the pavement as part of the flood recovery works and should ensure that it continues to benefit from this learning as part of the pavement maintenance programs moving forward.

The industry, and local government, have invested heavily in education of people, supply of plant and materials and have successfully delivered more than $1 billion worth of stabilisation to the Queensland market as part of the 2010 - 2014 flood recovery work.

Introduction (Department of Premier and Cabinet), October 2011) In the in 2010, 2011 and 2013 listed devastating natural disasters, with flooding The arrival of Cyclone Tasha resulted in and storm events of up to category 5 were exceptional flooding in many parts of central experienced in large sections of Queensland. and southern Queensland with almost every A number of different funding models were river in Queensland reaching major flood adopted to fund the recovery of the state levels during the period from 26 November owned road assets, as well as other areas. 2010 to 7 January 2011. This paper will highlight funding programs that were utilised and how stabilisation was Severe Tropical , a category 5 used as the preferred pavement rehabilitation system made landfall near Mission Beach on method. The paper will review sustainability 3 February 2011. The largest rainfalls were considerations that local government generally in the order of 200 - 300mm in the practitioners considered when selecting 24 hours to 9am on Thursday, 3 February pavement stabilisation. The paper will review 2011. There rainfall totals were experienced the resources that were provided to the State in the areas between and Ayr, causing including education, up scaling of contracting some flooding. plant and personnel as well as increased material supplies and improved specifications 9170 kilometres (27 per cent) of state-owned and testing. The paper will consider ways that roads were damaged. local government can continue to benefit from the utilisation of the increased capacity to the market.

Scope of the Natural Disasters

In Queensland there were two major periods of damage.

In 2010 and 2011 a series of floods hit Queensland, beginning in December 2010. Seventy percent of Queensland's Council areas were affected by weather causing flooding. (The State of Queensland • Kowanyama Aboriginal Shire Council • Lockyer Valley Regional Council • Mackay Regional Council • McKinlay Shire Council • Banana Shire Council • Bundaberg Regional Council • Burke Shire Council • Carpentaria Shire Council • Central Highlands Regional Council • Cloncurry Shire Council • Doomadgee Aboriginal Shire Council • Fraser Coast Regional Council • Gold Coast City Council • Gympie Regional Council • Hope Vale Aboriginal Shire Council • Isaac Regional Council • Lockhart River Aboriginal Shire Council • Logan City Council • Mapoon Aboriginal Shire Council • Moreton Bay Regional Council Figure 1 Queensland’s natural disasters compared to areas of Germany and France. Source: Queensland Government Department of Environment and Resource Management.

In 2013 similarly catastrophic weather conditions were experienced following Tropical .

5845 km (17 per cent) of state-owned roads were closed.

As at 15 February 2013, 54 regions throughout the State had experienced damage as a result of TC Oswald and the associated rainfall and flooding events. This damage activated natural disaster recovery assistance:

• Aurukun Shire Council • City Council • Burdekin Shire Council • Cairns Regional Council • Cassowary Coast Regional Council • Cherbourg Aboriginal Shire Council • Cook Shire Council • Etheridge Shire Council Figure 2 Queensland Natural Disaster • Gladstone Regional Council Relief and Recovery Arrangements • Goondiwindi Regional Council (NDRRA) activations as at 15 February • Hinchinbrook Shire Council 2013 ( Source : Emergency Management • Ipswich Regional Council Queensland, 2013)

Funding Models used to rebuild Australian government funding. (Queensland Government, 2014) The focus of this paper is to consider arrangements related to the State owned A breakdown of the funds specifically road assets and how the funding distribution allocated to stabilisation was not able to be models applicable to recovery were utilised in sourced from State Government or Federal Queensland. Government sources. Anecdotally the volume of spend appears to be in the order of Multiple models were applied to the disasters $1 billion over the 4 years 2010 – 2014. over the 2010 - 2011 period and the 2013 period: Overview of Stabilisation Processes applicable to the Recovery • National Disaster Relief and Recovery Arrangements During the 2011 - 2014 period the following (NDRRA) (Category B - processes were funded under the various Restoration Essential Public funding models for asset recovery: Assets) - joint funded federal- state government program; • Lime stabilisation of subgrades • State Disaster Relief • Stabilisation using lime, cement, Arrangements (SDRA) - blended cementitious and chemical wholly state funded financial binders of sub-base; and assistance package within • Stabilisation using lime, cement, Queensland; blended cementitious, chemical and • Local Government Grants foamed bitumen binders of base. and Subsidies Program - Local Government Floods Stabilisation is defined by AustStab as the Response; introduction of an additional material to the • Royalties for the Regions - existing pavement material to improve the Floodplain Security Scheme; engineering properties of the pavement. The • South West Queensland additional material is normally a single binder Flood Mitigation Fund; or a blend of binders. However, the • Natural Disaster Resilience incorporation of other aggregates is also Program (NDRP); and used to improve the grading or physical • Insurance for assets. properties of the original material. (AustStab Limited, 2011) Local government was responsible for preparation for a plan for disaster Stabilisation has the advantage of management in their local government area transforming an unsuitable material into a (Queensland State Government, 2003). product that conforms to Australian Following the 2013 events the model for Standards for pavement materials. In the recovery shifted the focus to building case of the flood recovery programs, the resilience in recovery, to ease the impacts in materials in the existing pavements were of those areas regularly affected. various ages, but in many cases were not at the end of their life, if it hadn't been for the The NDRRA funding process was activated if catastrophic events of the floods. However, expenditure estimates for eligible relief they were no longer suitable for use in the measures exceeded the small disaster pavement as a consequence of the flooding, criterion of $240 000. without a treatment such as stabilisation.

NDRP is a disaster mitigation and community resilience competitive grant program and is Sustainability of Stabilisation jointly funded by the Australian and Queensland governments. NDRP projects Economically, in the period 2010 -– 2014, are funded on a cost sharing basis, with the Queensland was already coping with strong applicant required to make a financial construction asset growth in the South East contribution in addition to receiving State and Queensland Market with projects such as the Gateway Motorway Project and the Eastern was significantly quicker than removing and Busway, catering for the increased population replacing quarry products. The process of shift to Queensland. In the North Western shaping and compacting was virtually Regions of Queensland resources were also identical to other construction methodologies. been drawn by the mining sector, which was in a period of record growth as a result of Effectively stabilisation allowed the growth in the Asian market. (SOURCE) rehabilitation practitioners to produce more rehabilitated pavements at a lower cost with As a result of the asset flood recovery there minimal finite quarry resources in a shorter was a massive upgrading of resources in the time period. Queensland construction market. This upgrading was in the area of human and The following case study demonstrates the natural resources; labour, plant, finances and sustainability of the stabilisation process as primary resources such as quarry products applied to the flood recovery process and binders. Strategically the local, state and federal government agencies responsible for Case Study the allocation of funding needed to find construction methodologies that would As a part of the NDRRA funded works, facilitate an efficient use of all of the these Townsville City Council rehabilitated resources. three sections of Hinchinbrook Drive, which were damaged by flooding, using Cement Stabilisation of all levels of pavement in Stabilisation techniques. rehabilitation allowed the existing pavement materials to be one hundred per cent Photos 1 and 2 show the distressed recycled, if the geotechnical conditions were pavement, which had an existing thin asphalt favourable. wearing course and some previous deep lift asphalt patches. The process allowed decision makers to make sound economic decisions, as the cost of the rehabilitation is recognised as being approximately thirty per cent cheaper than other remove and replace forms of rehabilitation, producing pavements with full whole of life (25 years) remaining and recycling the existing resources. (Wilmot, 1991) In rehabilitation of the pavement, finite virgin quarry materials were able to be retained for use in sectors of the construction industry that need virgin materials - such as new pavement construction, concrete and asphalt.

Socially the process was also sustainable. When stabilising existing quarry products Photo 1: Hinchinbrook Drive, Townsville - insitu the number of vehicle movements Pavement distress prior to stabilisation required to remove and replace quarry products was significantly reduced; as well as the volume of material being incorporated into the pavement being reduced by up to ninety-seven per cent.

The amount of time to complete the work was significantly reduced, as the materials were processed insitu instead of being removed and replaced, and then shaped and compacted. The incorporation of a binder

The 3.5% by weight of Flyash Blended Cement (75/25) was then incorporated into the pavement to a depth of 300mm using a Wirtgen WR2500K mixer with an enclosed spreader in front of the mixing box. The 22kg/m² of cement was pumped from the attached feed tanker into the enclosed spreader and mixed in, whilst incorporating water for moisture control from the water tank on the same feeder tanker. (Photo 3)

Photo 2: Hinchinbrook Drive, Townsville - Pavement distress prior to stabilisation

The scope of works was as follows:

• Pre-Pulverise and Shape • Remove and Replace unsuitable material if required • In situ Stabilise 300mm Deep at 3.5% FAB (1546m2 at 22 kg/m²) • Remove and replace material not accessible to stabiliser • Supply and place AMC7 Primer Seal Photo 3: Hinchinbrook Drive, Townsville - • Supply and Place SAMI Seal (S4.5S Pavement reconstruction - Blended or equivalent and including AB5) Cement • Supply and Place 35mm thick DG10 AC surfacing The stabilised material was then compacted • Traffic Control and required testing with a combination of large smooth drum roller, a twin drum smooth roller and a multi- A further requirement of Townsville City tyred roller while trimming to level. (Photos 4 Council was for the cement stabilisation to be & 5) completed using a stabilising mixer with an enclosed spreader to minimise dust during the operations.

Stabilised Pavements of Australia Pty Limited was contracted to undertake the works in the 2013/14 year.

After the traffic control was set out, the existing failed granular pavement, with its asphalt wearing course and subsequent patches, was initially profiled to 250mm depth using a 1-metre profiler. Some of the excess material was loaded out at this stage with the profiler. The pulverised material was then shaped and lightly compacted and additional material was trimmed off and loaded off site Photo 5: Hinchinbrook Drive, Townsville - to allow for the levels to be 45mm below final Pavement reconstruction - Compaction level. with smooth drum

The pulverising, shape correction and cement stabilising operations were completed on the three sections totalling 1,546m² in three days under traffic. (Photo 6)

Photo 8: Hinchinbrook Drive, Townsville - Pavement reconstruction - Final wearing course 35mm DG10 Asphalt

(Photo 8) Line marking, tidying up and reinstatement of signage was completed on Photo 6: Hinchinbrook Drive, Townsville - the sixth day. Hence, the full rehabilitation of Pavement reconstruction - Final pre- the flood damaged pavements in the three sealed pavement sections was completed using cement stabilisation in six working days under traffic. (Photos 9 & 10) The AMC7 Primer Seal and the SAMI Seal were applied on the fourth day of construction (Photo 7), while the 35mm layer of DG10 Asphalt was laid on the fifth day.

Photo9: Hinchinbrook Drive, Townsville - Pavement reconstruction - Completed pavement

Photo 7: Hinchinbrook Drive, Townsville - Pavement reconstruction - Post Sealing

Queensland Department of Transport and Main Roads (TMR) specifications and guidelines.

TMR revised and modified specifications such as MR 07C Foamed Bitumen Stabilisation to reflect the lessons learned, which are world leading, in the areas of foamed bitumen stabilisation.

To meet the plant requirements in Australia, as a result of the increased demand experienced as a result of the flood recovery work, the equipment suppliers improved their delivery to the market. Wirtgen incorporated Photo 10: Hinchinbrook Drive, Townsville roll over protection into the cab of the - Pavement reconstruction - Completed stabilisers as a standard item. (Yates, 2014) pavement Caterpillar benchmarked training in accordance with world best practice and significantly improved tailoring this training to The Executive Manager Construction and meet the needs of the market. The suite of Maintenance Benden Quabba commented drums for stabilisers available on the that the process has produced fantastic Australian market was adjusted to maximise projects that have been of the highest quality productivity and gradability of materials. (Lee, and value for money for the Townsville 2014) ratepayer and noted that it was a valuable way to protect our valuable resources. The binder suppliers responded to the increased demand with the ground ISO Advances in the Stabilisation process onsite storage for reliable supply of multiple following the Flood Recovery days of stock which improved the ability to provide a reliable supply designed to optimise At the start of the flood recovery period there production to any construction project. The were two accredited contractors servicing the supply of materials anecdotally increased Queensland market. Following the flood threefold. The number of supply points, as recovery there are ten stabilisation well as areas serviced significantly increased. contractors who are voluntarily accredited in An increased capacity to provide slag limes accordance with the AustStab ARRB and other blended materials to the market Stabilisation Accreditation scheme. The improved significantly. This provided industry association (AustStab) believes that increased flexibility into the Queensland this has improved the quality and reliability of market. (Dingle, 2014) the stabilisation process to the Queensland market. Sources of Materials In conjunction with the Centre for Pavement Engineering Education (CPEE) AustStab Prior to the flood recovery work supply of improved the education and knowledge of the stabilisation contractors, binders and market with the delivery of twelve courses experienced personnel in design, throughout Queensland to over four hundred construction and testing was far more limited. and forty delegates from local and state government as well as consultants and civil Supply points for the binders have not contractors. Courses were delivered by changed significantly since the flood recovery academic and industry experts as well as works, though the efficiency and capacity to stabilisation contractors. This improved the provide has in most cases significantly knowledge level of delegates in the areas of improved. design, construction and quality control in accordance with the Austroads, AustStab, How to sustain the benefits gained Conclusion

Following the flood recovery the stabilisation Pavement stabilisation and recycling was market remains within the Queensland heavily utilised as part of the pavement market as a sustainable resource to the construction methodology during the flood market as long as the demand for recovery period in 2010 - 2014 throughout stabilisation within Queensland remains. The Queensland. A number of different funding improvements to supply, products delivered, models were used to fund the works. Under contractors available and knowledge gained each funding model selection criteria, will be sustainable if engaged. stabilisation met and exceeded the requirements, including meeting the need to The techniques and processes adopted by generate pavements that would be resilient local government in Queensland can be for future climatic conditions. Stabilisation utilised in areas that local government areas provided sustainable solutions when (LGA) were not previously experienced in compared with the measures considered stabilisation in the pre 2010 climate. important to local government, including Following the flood events, the knowledge, being of sound economic reasoning and with experience and capacity to provide both consideration to whole of life utilisation of within the stabilisation industry and in the resources. broader construction industry has significantly improved. Significant advances were made in training, education, availability of suitable plant and At a time when the construction industry personnel as well as improvements in plant nationally is experiencing knowledge loss due technologies and material supplies. It is to an aging workforce and demands on the important that the local government now industry from the mining sector the looks forward and considers how to Queensland local government sector has incorporate lessons learnt, skills gained and been able to benefit by moving against the advances in stabilisation and pavement trends. This could be further continued by recycling to continue to benefit from the recognising the additional applications of devastation of the 2010 - 2014 flood events. pavement stabilisation throughout all levels of pavement construction in both new construction as well as pavement rehabilitation.

A question that has been raised is why does one LGA support stabilisation in one level of pavement, such as subgrade stabilisation, versus a bordering LGA that only stabilises another level, such as base courses? Confidence in the ability of the technology to perform in a resilient manner given the challenging climatic conditions could be gained by LGA sharing success stories, as well as lessons learned in pavement stabilisation through publications and information forums. The new pavements in many cases have since been tested by challenging climatic conditions and appear to be out performing other construction methods. This was evidenced by the TMR project Pittsworth Road, Oakey.

Bibliography Queensland Government.(2013) Queensland 2013 Floor Recovery Plan. Brisbane: AustStab Limited. (2011). Pavement Recycling and Stabilisation Guide . North Queensland State Government. (2003). Sydney, NSW, Australia: AustStab Limited. Queensland Disaster Management Act. Brisbane: Queensland State Dingle, W. (2014, July 21). Sales Manager, Government. Wagner Cement. (A. E. Leah Fisher, Interviewer) The State of Queensland (Department of Premier and Cabinet). (October Lee, A. (2014, July 21). Sales Manager, 2011). Premier's Disaster Relief Caterpillar Inc. (E. O. Leah Fisher, Appeal: Distribution Committee Interviewer) Report. Brisbane: Queensland Government. City of Townsville. (2013). Stabilising a Partnership. Townsville: AustStab Wilmot, T. (1991). Recycling Opportunities in Awards of Excellence. the Effective Management of Road Pavements. Local Government Queensland Government. (2014, July 21). Engineering Conference. Hobart, Natural . Retrieved from Queensland TAS. disaster mitigation and resilience Yates, C. (2014, July 21). Sales Manager, funding: Wirtgen Australia. (L. Fisher, http://www.dlg.qld.gov.au/grants-and- Interviewer) subsidies-programs/queensland- disaster-mitigation-and-resilience- funding.html

Author Biography

Warren Smith is an internationally recognised expert in the area of pavement stabilisation and recycling. Warren has demonstrated an enthusiasm for pavement stabilisation over a distinguished 40 year career in the industry.

Postal Address : PO Box 240, Gymea NSW 2227

E-mail : mailto:[email protected]

Leah Fisher is the Executive Officer at AustStab. Leah has extensive construction experience from a 20 year career in asphalt, spray seal and Stabilisation in Queensland, and Victoria. She has a passion for not-for-profit organisations and is also an active leader of Scouts Australia.

Postal Address: PO Box 738, Cherrybrook NSW 2126

Email : mailto:[email protected]