Concrete Roads: The New Economics
Concrete pavements are well known for their strength, durability and long life. In the past, however, they have also been associated with a high initial price tag.
Over the years, a number of life cycle cost studies have been conducted and concrete pavements have continuously prevailed thanks to the significantly lower maintenance and rehabilitation required. Concrete pavements are now also cost competitive on a first cost basis. The new paving reality is that comparative initial bid cost and life cycle cost assessments will increasingly favour concrete over asphalt in the foreseeable future.
Public officials across the country are faced with the increasing challenge of managing road assets on a stagnant or, in some cases, decreasing budget. It is more important than ever for government to critically evaluate paving material options and determine the best course of action when spending taxpayers’ dollars.
Concrete Overlays: Green Rehab for Black Asphalt Roads
Concrete overlays, formerly known as white-topping, inlays and ultra-thin white-topping, are just what the name suggests – laying concrete over asphalt, composite or old concrete pavements for environmentally friendly, long-lasting and cost-effective rehabilitation. Concrete overlays can rejuvenate busy intersections and asphalt roads rutted by heavy truck and bus traffic with a new, rigid surface that won’t rut or shove. Depending on the application, traffic requirements and condition of the asphalt structure, an overlay may be as thin as 50 mm or as thick as 200 mm or more.
Concrete overlays may be either bonded or unbonded. In general, bonded overlays are normally used for resurfacing and minor rehabilitation, while unbonded overlays are used to rehabilitate pavement that shows some structural deterioration.
CO2: Wood & Concrete
The Wood Industry says that Wood is Good, but let’s look at some facts.
- Wood (a tree) sequesters CO2 (absorbs it through photosynthesis). Their literature says this.
- Their literature does not say that Wood respirates CO2 (releases it when it is burned or rots). The quantity of CO2 that is being released from rotting wood killed by the pine beetle in British Columbia is more than all industries combined.
True Sequestration – an attribute long associated to wood – will only function if a tree or wood product is buried at its end of life. Researchers claim that wood or wood products (provided the latter does not contain inappropriate chemicals or adhesives necessary for durability and in engineered wood products used in structural applications) need to be buried 50-100 metres below ground for true sequestration to take place. Their literature does not say this.
- Their literature also does not say that:
- Deforestation accounts for 25% of the global CO2 emissions. The amount of energy (electricity, chemicals and GHG and CO2 release) that it takes to cut down trees, transport, process, manufacture and deliver wood and wood products is massive.
- Deforestation is also harmful to water runoff control and causes soil erosion.
- Wood is not a local material
CO2 & Asphalt
Did you know…Bitumen used for asphalt paving is not a local material, and has high Embodied Primary
Energy (the bitumen is a wasted energy source).
- 50% of Canada’s Oil is imported – about 0.8 million barrels per day.
- 5% of the world’s CO2 comes from Ocean shipping.
- Oil shortages and price hikes are the new reality