Roads and Works Conference Rod Ellis August 2012 Materials for Unsealed Roads – Developments in testing, additive/blending protocols and its place in Asset management

Introduction Local Government Research and Development Scheme Trialing new techniques for improving the composition of material used for unsealed roads

Outcomes Results of the 3 trial sites monitored over 3 years Protocol in the assessment process and decision making for material selection Monitoring forms and process Whole of life considerations

Purpose To better understand what makes a good material for unsealed roads (before it is used) To acknowledge the large volumes of material used in unsealed road construction and to attempt to become smarter by introducing some science to compliment practical experience Acknowledge some Councils Works Managers will not have years of local experience so setting up a framework and knowledge base to assist good decisions in material selection and treatment is critical for future success

Trial Process Pit Material testing against ARRB specifications Assess options to improved material properties –Blending –Additives –Adapting works practices Examine Whole of Life benefits of various treatments Setup and monitor trial sites Recording findings and reporting

Adelaide Hills Councils Dolomite and Monarto Material Polycom in sections Monarto, slightly finer grading,less loose material and wear

Goyder Drews Pit – 5 sections Polycom, Lime, Import material, bag lime in sections, untreated Imported material to PM specification - higher loose material and windrow development Lime not effective for low PI material Polycom seemed to work with the fines to reduce windrow development and loose material.

Loxton Waikerie Lowbank Road Dustcheck use to reduce dust No observable dust reduction Less rutting, windrow generation and loose material where additive used

Pit Material Key Learning 1 Local Government need to recognise the difference between commercial products for base course, sub base course and material from pits for sealed roads to those attributes which contribute to a good wearing surface for unsealed roads. Sealed Road Unsealed Road

Key Learnings

Where we want to get to

Key Learning Key Learning 2 Improve raw material before using additives Clear specification for grading and plasticity Pit operators need to blend stone, gravel and fines in proportion to develop acceptable material

The Thirds Rule 0.5mm 10mm

Blending at the Pit

Use of testing information More Clayey More Gravel

Key Learning Key Learning 3 Properties in the pit will be different on the road. Select the right equipment to suit the material Test post compaction from the road to determine compliance to grading and Plasticity

When to Grid Roll/Rock bust

When to crush and raw feed composition

Blending on the Road Bed

Additives »Key Learning 4 »For Drews Pit material at Goyder in hindsight the use of lime was inappropriate, however lime/fly ash may be an alternative in future trials. »Key Learning 5 »Polycom needs fines in the material to work. Further monitoring is recommended for each Council to determine if there is longer term benefits. After 2 years of monitoring there are positive indicators.

Monitoring The monitoring methodology used was deliberately made simple to allow Councils field staff. In all cases the field record sheets were designed to allow for a systematic and consistent approach to record keeping The visual assessment observed Dust, Corrugation, Potholes and Loose Material on a course rating of LOW, MEDIUM and HIGH. The site measurement assessment consisted of: –depth of rutting depth (mm) –window height (depth) mm –loose material (kg/0.5m 2 ) –Corrugations (depth mm, spacing (m))

Monitoring

Key Learning 6 Dust assessment discernment is very difficult visually. The extent of humidity at time of assessment i.e. overcast, clear or recent rain needs to be recorded. Key Learning 7 While visual assessment of loose material may not be discernible, the measurement of windrow height and loose material are more indicative. Key Learning 8 Trial sites should be left without maintenance grading interventions if possible to develop a longer term trend of deterioration. Several Councils undertook grading operation during the trial period.

Typical results

WHOLE OF LIFE

Protocol for Unsealed Road Performance

Application to the wider local government Promotion Roads Conference and SALGSOA groups Get other Councils involved Kingston and Kangaroo Island are planning trials Support Tonkin/ARRB through Rod Ellis and Bob Andrews Tools –Grading Assessment Tools –Material performance Charts –WOL Spreadsheets –Field Trial monitoring forms –Reporting Framework

Upskilling

Relating to Asset Management km of sheeted roads over 45 rural Councils $1.1 Billion Dollar asset in sheeted roads across the state $51 Million dollar annual re-sheeting across the state $1.1 Million dollar average re-sheeting /rural Council

Road Hierarchies Rate Resheetpercentresheet *percentlife life*per cent cat cat cat3a cat3b cat3c Ave Resheet$ 24, Ave Life22.5 Asset Life linked to service standards and associated costs example

Life Extension Impact across the state example km in the State$$/km Value of States sheeted roads Avera ge life Total Annual Resheeting Cost for State Saving for State with each extra year life average/Cou ncil (assume 45 Councils) Average Saving for Council Percen t saving ,163,332, ,703,670 1,148, ,163,332, ,503,5142,200,1561,100,07848,8924% ,163,332, ,482,9634,220,7081,055,17793,7949% ,163,332, ,620,8866,082,7851,013,797135,17313% ,163,332, ,899,3437,804,328975,541173,43018%

Life extension Hypothetically how can 4 year increase life be achieved example based on percentages in previous slide life comment cat11215Improve Material Properties cat21519Improve Material Properties cat3a2528both material and service level cat3b3035both material and service level cat3c3540Review service levels AVERAGE years increase in life

Benefit to Asset Management An Average 4 year life increase across network can result in $175,000/annum/Council less re sheeting (18% saving)

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