Road Strengthening Using Cold In-Situ Road Recycling Michael Malone B.Eng C Eng Midland Regional Authority March 21st , 2014

Irish Roads • In Ireland we have four main categories of road : Motorway, National, Regional & Local. The total road network length is approximately 95,700 km.

• Motorway : 1,200 km approx

• National : 3,500 km approx

• Regional Road : 12,000 km approx

• Local Road : 79,000 km approx

• Road strengthening refers to not only the rehabilitation of the surface but also to the rehabilitation of the deeper structure from which the road derives its strength. • Ireland has a greater length of road per capita than Hungary, Spain, Finland, Poland or Germany •The remainder of this presentation will refer to local & regional roads only. Sources : National Roads Authority, Department of Transport, OECD

Evaluation of Road Condition • In Ireland we use a method of rating road condition called the Pavement Condition Index (PCI). The scale is 1 to 10. 10 = Perfect Condition 1 = Not suitable to drive on • A PCI of ≤ 5 indicates problems beyond surface defects requiring structural repair/reconstruction. This is energy intensive and expensive. Its always best to intervene prior to this with surface treatment and minor drainage work etc.

Evaluation of Road Condition - Before L5554-0 Kyle Hill 2011 – PCI Rating 3

Evaluation of Road Condition -After L5554-0 Kyle Hill 2011 – PCI Rating 10 Following Strengthening In 2012. Photo Taken 07.03.14

Road Strengthening • Road strengthening refers to not only the rehabilitation of the surface but also to the rehabilitation of the deeper structure from which the road derives its strength. • Traditional Strengthening Methods – Wet Mix Macadam & Hot Macadam Overlays

Wet Mix Macadam • Regulate & apply 150 mm compacted Clause 806 (unbound layer) • Apply double surface dress • On average 345 kg of Cl 806 applied per m2 of road • Cl 806 is blasted & crushed in a quarry and must be transported to site

Hot Macadam Overlays

•Typically regulate where required (Clause 907)

• Apply Bond Coat IS EN 13808 –Emulsion 60% binder, approx 0.6 l/m2

• Dense Bitumen Macadam overlay 60 -100mm deep, Clause 906

•Finish surface with Double Surface Dressing (0.6 & 1.6 L/m2 Polymer Modified

Binder) or 40mm wearing course such as Clause 942 (Thin Layer)

•DBM Binder Content 3.4 – 5.6%

• Clause 942 Binder Content 4.8 – 5.8%

• All binders are bitumen based/oil derived. All of this bitumen must be imported

• These Macadams require rolling/compaction temperatures of at least 110 °c

therefore they have much higher temperatures in transit requiring significant

thermal energy input

Costs – Monitary Traditional Strengthening Methods €14 - €24 /m² Costs – CO₂ 2.9kg CO₂/m² The traditional strengthening methods particularly Macadams are know as “High Energy Pavements”. Is there any alternative ???

Cold In-Situ Road Recycling Two basic principles: • consider what is available in the existing road that will be useful in bringing the road back to good condition and use this to reduce inputs rather than just overlaying new inputs on top of it

• apply the specifically developed aggregate binder on site at ambient temperature

Cold In-Situ Road Recycling Determine Additional Material Required & Apply

Cold In-Situ Road Recycling Wirtgen Road Recycler Preceded by Tar Tank

Cold In-Situ Road Recycling Recycling Milling Head (Source : Wirtgen GmbH)

Cold In-Situ Road Recycling TDEL Patented Profiler & Screed for Recycling

Cold In-Situ Road Recycling TDEL Patented Profiler & Screed with Geogrid Application

Cold In-Situ Road Recycling

Results from Laois County Council –Western Area Road Strengthening Program 2012

•125033 m² of road (regional & local) was recycled at a total cost of €1,045,841 incl VAT

•This is an average cost of €8.36/m².

•The alternative road strengthening methods range in cost from €14 – 24/ m² incl VAT

• Cost Saving of over 40%

•On average 145 kg/m² of new quarry material was applied

•In 2011 on average 345 kg/m² of new quarry material was applied

• This 58% reduction in imported quarry material was possible due to using the existing

useful material already in the road with no compromise in finished road quality

• The problems traditionally associated with significantly increased road elevation were

also avoided as the Cold In-Situ Road Recycling process generally results in only

marginal increase in road elevation by using the existing granular material in the road

• Most Important : 56% reduction in CO₂ , 200 Tonnes Saved in 2012 in a single roads

operational area

Cold In-Situ Road Recycling Performance Parameters & Results

Performance Parameter

Stiffness 1250Mpa Wet Strength 17 kN Dry Strength 30 kN

Minimum Achieved

1310 17 31.5

Maximum Achieved

3166 29.8 61.7

Average 2263 19.4 44.3

Average Binder Content 3.4 %

Cold In-Situ Road Recycling Duriez Crushing Test

Cold In-Situ Road Recycling Results •The quality of the roads strengthened has been subject to visual inspection and testing as per the performance parameters specified in the tender and contract. All of the parameters set have been met •Significant reduction in truck construction traffic and significant energy reduction on roads where previously hot macadam overlays would have been used. All of the above confirmed the estimated 50 – 60% reduction in CO₂ emissions •The first Regional Road (R433-57) Ballacolla which we recycled in 2010 has endured a severe winter (-15 °c ) through 2010/2011, hot summer (30 °c ) in 2013 and significant increase in HGV traffic due to motorway tolling. The road has given excellent service with no maintenance or intervention •Increased volume of roads strengthened from decreased financial resources

Other Issues To Consider •EU member states have a binding obligation to reduce CO₂ emissions by 2020. This target can only be achieved by the involvement of all the stakeholders including government, private firms, communities and local authorities • Green Tenders – An Action Plan on Green Public Procurement launched in January 2012 by Minister for Public Expenditure & Reform- Brendan Howlin and Minister for Environment Community & Local Government Phil Hogan, specifies construction and transport in the eight priority service groups to be included within the 50% public procurement target for Green Tenders

Cold In-Situ Road Recycling What To Watch Out For • Put a clear robust Client Specification in place at tendering. Specify performance results & allow for innovation by market . Back this up with the relevant Department of Finance Contract. Laois County Council Specifications available at www.laois.ie. • Provide practical, useful test data for the existing roads • Evaluate tender competency – this process is not for the inexperienced

• Deal with drainage issues prior to strengthening • Have regard to edge strength • The curing process is temperature/time dependent

• Collect, review & make your pre and post construction test data available. The rest of us need it and can learn from it

Presenter

Presentation Notes

Road Strengthening In Ireland we have four main categories of road : Motorway, National, Regional & Local. This presentation refers to local & regional roads only. Road strengthening refers to not only the rehabilitation of the surface but also to the rehabilitation of the deeper structure from which the road derives its strength.