An article from “Canadian Concrete Online Concrete Magazine”-Issue 03, April 2021 includes a multitude of concrete options to maximize pavement longevity, while maintenance costs remain low.
Göbekli Tepe-earliest known use of limestone in a structure.
Click to enlarge
CONCRETE STRUCTURES IN HISTORY:
(from 2017 ISCP article “Rock Solid History of Concrete—How Limestone, Rocks, and Volcanic Ash Built the Modern World”: Concrete History Article):
Concrete structures have existed for more than 12,000 years:
10,000 BCE to 8,200 BCE:
The earliest known use of limestone in a structure was found in the Göbekli Tepe temple in modern-day Turkey, from about 10,000 BCE—7,000 years before the Great Pyramid of Giza. Göbekli Tepe is the oldest known example of monumental architecture—the first structure human beings put together that was bigger and more complicated than a hut. The cleanly carved, T-shaped pillars of the Göbekli Tepe were made of limestone—splashed with bas-reliefs of animals.
2325 BCE:
One of the Seven Wonders of the Ancient World, the pyramid of Giza is the oldest, largest of the three pyramids bordering what is now El Giza, Egypt, and only one to remain largely intact.
CONCRETE PAVEMENTS IN HISTORY
(from “Stay Connected” Canada’s Only Online Concrete Magazine (Canadian Concrete Expo)):
ASPHALT has a long history with road construction, but after concrete road construction was introduced,
“Here started the better roads movement”:
• 2500 years ago…around 479 BCE
Babylonians began applying ASPHALT as makeshift roads, which involved applying a common waterproofing agent to stone paths thereby waterproofing them and creating a better travel experience.
• Around that time, people first started applying asphalt as a mortar between stone bricks, then little innovation occurred.
• 18th Century:
John Metcalfe and Thomas Telford, two Scots independent of each other, paved more than 1,700 kilometers of ASPHALT roads. Metcalfe accomplished his part despite being blind.
• John Louden McAdam created a better version of ASPHALT pavements of stones and asphalt, called “tarmacadam” pavements—the term and method are sill in use today.
• A few decades later:
ASPHALT entered North America. Edward De Smedt, Professor Columbia University and Belgian immigrant created a “well-graded, maximum-density” asphalt, which he called “sheet asphalt pavements”.
• 1865
WORLD’S first CONCRETE PAVEMENT was built in Inverness, Scotland
• 1872
CONCRETE PAVEMENT in Edinburgh, Scotland—is still in use today!
• 1872:
Roadbuilders used the ASPHALT mix design to pave the streets Battery Park and Fifth Avenue, New York City, USA
• 1877:
Used the ASPHALT mix design to pave Pennsylvania Avenue, Washington, D.C.
From ISCP article: “125th Anniversary Commemoration & Tour of First U.S.
Concrete Street Held in Bellefontaine, Ohio (Audio & Video)” Click to go to article.
• 1891:
CONCRETE PAVEMENTS in North America! George Bartholemew convinced the City Council of Bellefontaine, Ohio to use his CONCRETE MIX DESIGN as a paving material. He guaranteed it would last at least 5 years. The city paved Court Avenue with concrete.
When [Court Avenue] turned 100 years old, the city erected
a statue of Bartholemew and a plaque that reads:
“Here started the better roads movement.”
Click to enlarge
Lori Tiefenthaler, Sr. Director of Marketing of Lehigh Hanson, Inc., and past Chair of the American Concrete Pavement Association (ACPA) said, The greatest benefits to concrete roads are durability, safety, sustainability, and long life. “Concrete provides a 50-year life-cycle and it can be optimized to meet so many conditions, with the increasing focus on resilience of pavements, I believe concrete will become the go-to building material for pavements.”
Concrete pavements are on the rise, especially with the growth of concrete overlays on existing pavements.
Asphalt is nearly synonymous with road construction in Canada, but time has shown how vital concrete pavements have become.
2001:
In Ontario, Canada, the Ministry of Transportation Ontario (MTO)—the single largest owner of road and highway infrastructure in Canada—initiated the “Alternative Bid process for freeway reconstruction contracts. This process allows for bidders to prepare their construction bid based on either a concrete or asphalt pavement design, and just like all construction projects, the lowest bid wins.
Stephen Lee, P. Eng. Head, Pavements Section-MTO said, “A majority of those contracts include various asphalt items.” And, the contracts include about 100 kilometers of in-place recycling asphalt with cement as a stabilizing additive.
Tiefenthaler explained, “Concrete is often competitive in upfront costs verses an equivalent asphalt structure. However, you have lower costs over the life of a concrete asset.”
The MTO considers life cycle costs over a 50-year period, so the higher upfront costs of concrete can be offset by the lower maintenance costs of concrete. The 50-year life cycle costs, including maintenance costs strategies and schedules, were developed based on MTO’s experience with concrete and asphalt pavements and in consultation with both the asphalt and concrete industries.
Lee added, “Our life-cycle cost analysis (LCCA) takes into consideration the initial construction cost as well as estimated future maintenance costs over a 50-year maintenance cost, the lowest final bit wins the contract.”
2017:
Joe Tomlinson, Contracts Manager, Concrete Specialties-Aecon, explained that on an awarded contract, the company chose to use concrete instead of asphalt, and to tear out and replace approximately 10 kilometers of Highway 401 near London, Ontario. For Aecon, it was a new opportunity they believed was “a more reoccurring item on many MTO contracts”, and that the MTO said both rigid and flexible pavement design options were feasible alternatives based on the scope of the project, constructibility, service life, and life-cycle costs.
2018:
Aecon completed the work. Tomlinson admitted it was a little more challenging because concrete placing has a limited window, it needs to be precise during setup, or it would have to be reconstructed. But, every job is a learning process!
A CONCRETE FOR EVERY OCCASION:
“Concrete pavements are versatile because they can be placed in many applications because they are versatile due to the various forms of cementitious materials that can be used to construct new slipform concrete pavements or rehabilitate existing ones,” said Tiefenthaler. Versatile use for:
• airports
• highways
• municipal streets
• county roads/highways
• industrial facilities
-large parking areas
-test tracks
-truck stops
-toll plazas
-[docking yards]
-[intermodal facilities]
-more…
Concrete innovations and solutions that have advantages over asphalt:
FUL-DEPTH CONCRETE PAVEMENTS
ROLLER COMPACTED CONCRETE (RCC): Developed in the 1970s for stabilization of logging roads in North America, RCC is a zero-slump concrete placed with standard or high-density asphalt paving equipment with a tamper bar for initial compaction. Then a larger roller is used to compact the pavement to achieve final density. RCC is diversified in:
• log handling yards
• intermodal terminals
• freight depots
• roads and highways
CONCRETE OVERLAYS:
Also known as “whitetopping” is a sustainable and cost-effective solution to improve the overall performance of a pavement. It is concrete over:
—asphalt
—concrete
—composite pavements
Click to enlarge
Sherry Sullivan, MASc, P.Eng, LEED AP, Business Development and Pavement Engineer-Forta Concrete Fiber said, “Concrete Overlays are a great repair alternative to repaving failed asphalt pavements. There is a long and successful history in the use of concrete overlays—more than a century of progress! Can be done over asphalt or concrete without the need to tear up what’s underneath, as we can design the pavements as a monolithic structure.”
THIN CONCRETE PAVEMENTS (TCP):
Also known as “short-slab design” is a method that has demonstrated that it can often cost less than asphalt for the same service life. Sullivan said, “TCP has proven to compete against asphalt in most applications including parking lots, but illustrates the most savings in any facility with over the road truck traffic:
-Distribution centers
-industrial facilities
-highways
-country roads
They:
-curl less
-provide a smoother ride
require less thickness/less material than traditional designs
–macro synthetic fiber addition into TCP gives better performance over its lifetime in the post-cracking stage, controls cracking settlements due to inhomogeneities in the supporting surface of the concrete slab.”
FULL-DEPTH RECLAMATION (FDR):
A rehabilitation method that recycles existing asphalt pavement and the 6-to-10-inch subbase into a new base layer mixing/using cement. Benefits include a base that is capable of withstanding greater weights as it is:
—stronger
—more uniform
—more moisture-resistant
—less costly pavement rehabilitation method
Sullivan added, “And, although it’s widely recognized that traditionally designed concrete pavements can often outlast asphalt, they have also generally been more expensive up front. Newer mechanistic-empirical pavement design methods (MEPDs) are demonstrating concrete can now compete on a first-cost basis, while providing better performing concrete pavements.”
April 23, 2021 Issue (Issue 03) of “Stay Connected” Canada’s Only Online Concrete Magazine (Canadian Concrete Expo) titled “Why Aren’t All Pavements Concrete?”: https://stayconnected.canadianconcreteexpo.com/view/10857533/8/
ISCP article titled “Rock Solid History of Concrete—How Limestone, Rocks, and Volcanic Ash Built the Modern World” by Amy M Dean, Editor-in-Chief-ISCP: www.concretepavements.org/2017/10/18/rock-solid-history-of-concrete-how-limestone-rocks-and-volcanic-ash-built-the-modern-world/
ISCP article titled “125th Anniversary Commemoration & Tour of First U.S. Concrete Street Held in Bellefontaine, Ohio (Audio & Video)”: www.concretepavements.org/2016/04/28/125th-anniversary-celebration-tour-of-first-u-s-concrete-street-held-in-bellefontaine-ohio-audio-video/