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Roading plays a critical part in New Zealand’s infrastructure and remains one of the Government’s biggest areas of infrastructure expenditure. The Government is spending around $12.2 billion in state highways over the next 10 years, including making further progress on the Roads of National Significance.

While concrete roads are in widespread use throughout the world, New Zealand roads are still largely constructed using asphalt – despite growing evidence that concrete is cheaper, lasts longer, and offers various environmental benefits.

The Cement & Concrete association of New Zealand (CCaNZ) believes concrete should play a considerable role in New Zealand’s roading infrastructure programme. It is confident that the case for concrete roads is so compelling that Government must consider it a credible option.

However, CCaNZ is concerned that “asphalt thinking” has become institutionalised within central and local government agencies, and the contracting industry, to the extent that strong political leadership will be required to support a change in mind-set.

Concrete road (with traction and drainage grooves). Image: Britpave

SUmmaRy – THE BENEfITS Of CONCRETE ROaDSCONCRETE ROADS ARE LESS EXPENSIVEResearch indicates that concrete roads are cheaper than asphalt alternatives over a 30-years life as the components of concrete are not subject to the volatile price of oil or international exchange rates. The reduced maintenance requirements for concrete roads also contribute to their cost competitiveness.

CONCRETE ROADS LAST LONGERThe enhanced durability and low maintenance characteristics of concrete roads ensure that their service life is prolonged. The strength and robustness of concrete safeguards the road from excessive wear and tear, even under heavy traffic loads. When repairs are required they are typically smaller in scale than on asphalt roads.

CONCRETE ROADS ARE SAFEConcrete roads can be easily textured to suit specific requirements in terms of traction and skid resistance, as well as quietness. Concrete also reflects high levels of light to enhance driving visibility, particularly from street lighting at night. Concrete median barriers have proven successful in preventing head-on collisions.

CONCRETE ROADS SAVE FUELThe rigidity of concrete prevents heavy vehicles deflecting the road surface and creating “rolling resistance”, as is the case with asphalt roads. Less rolling resistance enhances fuel efficiency to help save money as well as reduce emissions.

CONCRETE ROADS HAVE ENVIRONMENTAL BENEFITSIn addition to lowering vehicle emissions through improved fuel consumption, concrete roads are also completely recyclable. Once crushed, the concrete can be re-used in a range of infrastructure projects. Recycling also helps speed up concrete’s ability to absorb atmospheric CO2, as it exposes greater surface area through which sequestration occurs. Concrete production can incorporate waste material from other industries, such as fly ash and slag. Concrete’s light colour (albedo) reflects greater levels of solar radiation than darker roading materials, to help slow climate change.

STUDy INDICaTES CONCRETE ROaDS aRE 25% CHEapERNew analysis by Infometrics1, commissioned by CCANZ, indicates that concrete roads are potentially 25 percent cheaper than asphalt roads over a 30-year life span. Building concrete roads could cut hundreds of millions of dollars from the cost of major New Zealand roading projects – money that could be put to good use elsewhere.

Infometric’s findings took into account international prices, price volatility, the cost of carbon emissions and travel time disruption.

The report found that the price volatility of oil compared with concrete is a material factor in why concrete roads are cheaper than asphalt alternatives.

The price of concrete is more stable, while bitumen is closely tied to unpredictable and unstable global oil prices and the US/NZ exchange rate.

The predicted future trend of oil and concrete prices look to further enhance the case for concrete roads. Petroleum Product prices have risen 180% since 1994 and look likely to continue to increase annually at 5.8%. This is compared to a rise of just 44% in concrete prices over the same period, with a projected annual increase of 2%.

To a large extent, this price premium for Petroleum Products reflects the costs associated with an uncertain overseas supply market. In contrast, the low annual price increase of 2% associated with concrete construction is due to the stable nature of domestic sources.

Construction and maintenance costs constitute the largest components of roading investment, but disruptions to travel time, caused by road maintenance, is also a factor. The report found that an asphalt road incurs greater disruption to traffic over its service life than its concrete counterpart. Concrete roads have a long service life of around 40 years, considerably longer than asphalt roads.

This is partly due to concrete having superior strength, with an estimated life cycle of up to 150% greater than asphalt. During their service life concrete roads do not require frequent repair or patching like asphalt roads, thereby drastically lowering infrastructure costs.

Overall the difference in CO2 emissions associated with

concrete and asphalt roads is not significant. However, concrete roads have a range of environmental benefits, such as less tyre rolling resistance and in turn lower fuel consumption, particularly for heavy vehicles.

The report also found that some roading contracts include an escalation clause for the price of bitumen or oil. This transfers risk from the supplier to the client (e.g. The New Zealand Transport Agency (NZTA)) and can have the effect at the tendering stage of making an asphalt surface look cheaper than it really is. The escalation clause is essentially an implicit subsidy for one type of construction material in preference to any other.

Concrete Roads

Prepared by Infometrics LtdMay 2013

for Cement and Concrete

Association of New Zealand

The Case for

pOTENTIal SavINGS ON ROaDS Of NaTIONal SIGNIfICaNCETaking into consideration the findings of the Infometrics report, if concrete was used for the entire Roads of National Significance programme the savings potential would be $3.05 billion.

To put this into perspective a saving of this magnitude is:

• more than the estimated Auckland City Rail build (costed at $2.86 billion)2

• significantly more than the Wellington Northern Corridor (Levin to Wellington) project (estimated at $2.4 billion)3

• 40 times the Governments expected $75 million 2014/15 surplus4

Applying this to the $1 billion build of Transmission Gully5 would save the Government around $251 million, which is enough to fund the entire New Zealand Road Safety Programme for a full year6 or insulate 115,000 homes as part of the Healthy Homes insulation programme7.

A $3.05 billion saving is also broadly equivalent to the Government’s total budget for all of New Zealand’s tertiary institutions for a whole year8.

The potential financial benefits to New Zealand are of such significance that, beyond the concrete industry’s own analysis, key decision makers must seriously examine concrete as a road paving alternative. Why wouldn’t they? Particularly when concrete roads also compare favourably, or out perform, asphalt roads when non-financial factors are considered.

SafETy aDvaNTaGES Concrete roads are as safe as asphalt roads – in fact they have a number of advantages.

Roads built using concrete can be tailored to produce excellent skid resistant textures to best meet specific dry or wet requirements9.

As a non-combustible material, concrete is more suited for use in tunnels as it reduces fire risk10.

Concrete’s light colour reflects street lighting better to enhance driver vision at night11.

Concrete median barriers have been successful in averting motorway accidents, particularly in preventing head on collisions and thereby helping to reduce the road toll12.

ENvIRONmENTal aDvaNTaGES Concrete roads are in many respects better for the environment. The primary energy required to construct, maintain and rehabilitate a concrete highway is three times lower than that of its typical asphalt equivalent13.

Concrete optimises resources. With a longer life-cycle and with less maintenance required, concrete places lower demands on raw materials and natural resources than asphalt14. Concrete

production can include by-products from other industries, such as fly ash and slag, for a positive net environmental impact15.

Concrete is also 100% recyclable, and can be broken down and used in new roading construction or other infrastructure projects (such as land reclamation)16.

Reports by the Massachusetts Institute of Technology17 in the United States found that concrete roads help to dramatically lower transport emissions. This is achieved by being less abrasive on vehicle tyres, as well as reducing rolling resistance. This enhances the fuel efficiency of heavy vehicles and lowers their carbon footprint.

Image: ACPA

Exaggerated depiction of a truck tire deflecting an asphalt road (left) but not a concrete road (right).

Concrete roads have the potential to help slow the process of global warming in a number of respects. Firstly, concrete roads provide a possible sink for sequestering atmospheric CO2 - a process that occurs more rapidly when a concrete structure is eventually demolished and recycled18 to reveal greater surface area.

Secondly, the albedo of concrete (the ratio of the reflected solar energy to the total solar energy received) is higher than asphalt19. This means the light coloured surface of a concrete road translates to greater radiation reflectivity, which can assist to slow climate change.

DRIvER aDvaNTaGES Concrete roads are better for drivers – making indirect savings for the more than three million Kiwi road users. They can lower fuel consumption by having a smoother surface texture, which reduces friction20. The smoother surface also lowers wear and tear on tyres and vehicle parts, meaning less maintenance costs for vehicle owners21. Driving comfort is also enhanced22.

As concrete roads require minimal maintenance, fewer road works and traffic disruption result. This helps lower fuel consumption from idling vehicles, increases productivity, reduces travel time, and minimises inconvenience to communities, businesses and road users23.

Many New Zealand asphalt roads have a chip seal, which is noisy to drive on. Concrete roads by contrast offer a range of quiet surface textures that reduce noise pollution and enhance driver comfort24.

Concrete roads also offer earthquake-resistant advantages, and are as seismically resilient as other roading materials. For instance, reinforced concrete roads resist splitting and cracking during seismic activity25, testament to which is their uptake along the west coast of America and in Japan26.

Concrete road under construction. Image: Wirtgen GmbH

Concrete median barrier. Image: BritpaveConcrete intersection. Image: CCANZ

Retexturing machine. Image: Britpave

Retexturing of concrete road. Image: Britpave

AFTERBEFOREImages: RMCAO

REFERENCES

1 Dr Stroombergen, A., The Case for Concrete Roads: For Cement and Concrete Association of New Zealand, Infometrics, 2013

2 Auckland Transport, City Rail Link, https://www.aucklandtransport.govt.nz/improving-transport/city-rail-link/Pages/default.aspx, found 20 August 2013

3 Hon English, B., National Infrastructure Plan, http://www.infrastructure.govt.nz/plan/mar2010/nip-mar10.pdf, found 20 August 2013

4 Hon English, B., Responsibly managing the Government’s finances, http://www.treasury.govt.nz/budget/2013/speech/03.htm, found 20 August 2013

5 NZ Transport Agency, Public-Private Partnership (PPP) for Transmission Gully Highway Questions and Answers, http://www.nzta.govt.nz/projects/transmission-gully/docs/ppp-qas.pdf, found 21 August 2013

6 Treasury, Vote Police, http://www.treasury.govt.nz/budget/2013/estimates/est13police.pdf, found 20 August 2013

7 Energy Efficiency and Conservation Authority, Warm Up New Zealand: Healthy Homes, http://www.eeca.govt.nz/eeca-programmes-and-funding/programmes/homes/insulation-programme, found 20 August 2013

8 Treasury, Vote Tertiary Education, http://www.treasury.govt.nz/budget/2013/estimates/est13tered.pdf, found 20 August 2013

9 Fleischer, W., Wolf, T., Skid resistance of concrete pavement surfaces: Practical experience in Germany,10th International Symposium on Concrete Roads, 2006

10 Rens, L., Concrete Roads: A Smart and Sustainable Choice, European Concrete Paving Association, 2009

11 N.A., Concrete roads enjoy clear advantage over bituminous roads, says Sharan workshop on cement concrete roads, http://commerce.nic.in/PressRelease/pressrelease_detail.asp?id=2263, found 20 August 2013

12 British In-Situ Concrete Paving Association, New in-situ concrete safety step barrier – FAQ’s, British In-Situ Concrete Paving Association, 2005

13 Athena Sustainable Materials Institute for Cement Association of Canada, A life cycle perspective on concrete and asphalt roadways: Embodied primary energy and global warming potential, Athena Sustainable Materials Institute for Cement Association of Canada, 2006

14 American Concrete Pavement Association, Green Highways: Environmentally and Economically Sustainable Concrete Pavements, http://www.pavements4life.com/QDs/SR385P.pdf, found 20 August 2013

15 Gadja, J., Vangeem, M., A comparison of six environment impacts of Portland cement concrete and asphalt cement concrete pavements, Portland Cement Association , 2001

16 American Concrete Pavement Association, Green roadways: Environmentally and economically sustainable concrete pavements, American Concrete Pavement Association, June 2011

17 Massachusetts Institute of Technology, Model based pavement-vehicle interaction simulation for life cycle assessment of pavements, Massachusetts Institute of Technology, 2012

18 Rens, L., Concrete Roads: A Smart and Sustainable Choice, European Concrete Paving Association, 2009

19 Rens, L., Concrete Roads: A Smart and Sustainable Choice, European Concrete Paving Association, 2009

20 Akbarian, M., Gregory, J., Ulm, F., Greene, S., Where the Rubber Meets the Road, Massachusetts Institute of Technology, February 2013

21 Banerjee, S., The Case for Concrete Roads, Construction Week Online, May 2010

22 Cement Association of Canada, Concrete thinking in transporting solutions: Building better highways in Canada, Cement Association of Canada, 2007

23 American Concrete Pavement Association, Green roadways: Environmentally and economically sustainable concrete pavements, American Concrete Pavement Association, June 2011

24 Iowa State University, Sustainable concrete pavements: A manual of practice, Iowa State University, January 2012

25 Bronwyn Torrie, Call for concrete highway as quake escape, http://www.stuff.co.nz/dominion-post/news/4870104/Call-for-concrete-highway-as-quake-escape, found 21 August 2013

26 Akiyama, H., Shimbun, Y., Cost-efficiency paving way for concrete, The Daily Yomuiri, January 2013

27 Akiyama, H., Shimbun, Y., Cost-efficiency paving way for concrete, The Daily Yomuiri, January 2013

28 Radhakrishnan, S., Planning Board panel moots concrete roads, The Hindu, March 2013

29 N.A., China moves on concrete highway plan, http://www.worldhighways.com/categories/materials-production-supply/news/china-moves-on-concrete-highway-plan/, found 20 August 2013

30 N.A., Future asset management issues Part 2: Impacts of peak oil with increases in bitumen and fuel costs on road use and asset management funding, Austroads Ltd., May 2013

GlOBal TRENDSBuilding roads from concrete is a standard construction practice in many countries around the world. Due to rising oil prices and a tighter fiscal environment, concrete is becoming a more attractive option for infrastructure investment globally.

Japan is building more of its roads with concrete, recognising its durability and cost-efficiency. Over its life-cycle, the Japanese Land, Infrastructure, Transport and Tourism Ministry estimate concrete is 30% cheaper than asphalt27.

The Ministry of Road Transport and Highways in India noted that modern society cannot function effectively without

concrete roads. The Minister noted that through the use of concrete vehicle operating costs are lower, construction faster, traffic disruption minimised, and maintenance reduced28.

China plans to build a proportion of its new 421km highway network (connecting Xingtai in Hebei province to Fenyang in Shanxi province) in concrete. While earlier concrete road technologies did not live up to expectations, recent advancements have convinced Chinese authorities to commit to building in concrete29.

Australia has recognised the impact of rising oil prices for road asset management and the need to carefully manage the consequences of this as prices continue to increase30.

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© Copyright November 2013 Cement & Concrete Association Of New Zealand (CCANZ).Disclaimer: The information provided in this publication is intended for general guidance only and in no way replaces the

services of professional consultants on particular projects. No liability can therefore be accepted by the CCANZ for its use.