Concrete Pavements in Action
Concrete that drains
Most people consider concrete to be impervious - after all, it's used to make water-retaining structures. Indeed, most concrete is nearly watertight.
However, a new kind of concrete that allows water to flow through virtually unimpeded is gaining popularity. Pervious concrete is being used mainly for construction of sidewalks, bike paths, playgrounds and erosion control. Pervious concrete pavement is not suitable for areas subject to high traffic volumes or speeds.
Advantages include keeping pavement surfaces dry, even in wet situations; allowing water and air to get to tree roots in parking areas; collecting and retaining water for use in irrigation; and allowing stormwater to infiltrate into the ground to replenish groundwater levels.
More information from www.pervious.com or www.nrmca.org
Concrete Construction, June 2005
Ultra-thin concrete for IDOT's parking lot: adding 20 years of life to a worn-out asphalt parking lot
The need to resurface a huge, deteriorating asphalt car park at the Illinois Department of Transportation in Schaumberg, grew into a demonstration project to install an ultra-thin whitetopping (UTW) overlay which IDOT will monitor for performance over time.
The article describes the properties of UTW, the issues that should be considered to establish whether UTW is suitable for a particular application, and the mixes used.
The project is important because, not only does IDOT have a car park that looks like new and has a long service life, it has also resulted in the formulation of a concrete mix design that makes UTW overlays competitive with asphalt overlays. More information from American Concrete Pavement Association
Concrete Construction, Dec. 2004
Visit a new "Concrete Roads Zone" today
The authoritative Roads & Bridges magazine has introduced a new section to its market-leading website. Designed to provide a better understanding of the topics addressing key issues and how they affect the user, the "Zone" offers: industry articles from the archives of the magazine; frequently asked questions; product news; and an "ask the expert: section. For more on the concrete road industry visit: www.roadsbridges.com
Get in, get out, stay out! Caltrans proves the effectiveness of a pavement renewal approach
The article gives the background to the week-long workshop held in 2000 to brainstorm innovative technologies focused on practical solutions to produce good riding surfaces lasting 40 years with minimum maintenance. The proceedings can be ordered online from: http://gulliver.trb.org/publications/sp/getin_getout_stayout.pdf
The article also describes the success of projects undertaken based on the results of the workshop, eg the experimental project on the south portion of the I-710. This achievement may serve to encourage application of the principles to renewing other freeways.
The Accelerated Construction Technology Transfer Team is also discussed along with its workshops that aim to provide the skills to complete projects faster, safer and better. More information from: http://www.fhwa.dot.gov/construction/accelerated/index.htm
TR News 232 May-June 2004
The economic benefits of concrete road pavements
The Cement and Concrete Association of New Zealand has released a new publication, TR 12, that examines the economics of using concrete for roads.
In the introduction it states that, while historically New Zealand was constrained to use the cheapest first cost option for its road network, it is now able to take a more sophisticated approach and conside long-term user and maintenance benefits of pavement types.
The Transfund New Zealand Pavement Evaluation Manual is the accepted framework for economic calculation of the merits of road works. This report provides specific guidelines and commentary on applying the principles of the Manual to evaluating concrete relative to competing pavement options. The C&CI Information Centre has a copy of this report, or it can be downloaded or ordered from: http://www.cca.org.nz/cca/shop/index.asp
Paving with roller compacted concrete
"This is the finest product for city streets to come along in years," says Marty Savko of Nickolas Savko & Sons, Columbus, Ohio. "I first read about roller compacted concrete (RCC) pavement in 1995..did some research then sent our engineers to learn more. Since 2001, over 100 street projects have been constructed with RCC pavements in central Ohio."
Gahanna city engineer Karl Weatherholt says:"We like RCC for residential street rebuilds. We're able to get residents back on the street much faster than with an ordinary concrete base."
More information on RCC pavements from http://www.cement.org/pavements
Concrete Construction, February 2005
Design-construction of a precast, prestressed concrete pavement for Interstate 10 El Monte, California
In April 2004 CALTRANS completed the construction of a precast, prestressed concrete pavement demonstration project that allowed it to evaluate the viability of precast pavements for rapid pavement construction and rehabilitation. It also allowed local contractors to become familiar with an innovative construction technique. Most of the construction took place at night when lane closures were permitted. The project added 8 m of traffic lanes and 3 m of shoulder to existing lanes.
To maximise performance, the precast concrete panels were pretensioned in the transverse direction during fabrication, and post-tensioned in the longitudinal after installation. The project demonstrated the expediency of precast concrete pavement construction and has generated interest for further applications.
PCI Journal, March-April 2005
Pervious concrete pavements
The Portland Cement Association has released a new report that examines a unique and effective means of meeting growing environmental demends. By capturing rainwater and allowing it to seep into the ground, pervious concrete replenishes groundwater, reduces stormwater runoff and its use is among the EPA's Best Management Prectices. This technology eliminates the need for retention ponds, swales and other stormwater management devices.
Report EB302.02 can be ordered from PCA at http://www.cement.org/bookstore
New concrete options for road designers
In this article, Bryan Perrie explains that, although concrete has traditionally been used in heavily trafficked freeways, it has application for rehabilitating ashalt pavements and constructing low-volume roads. He examines concrete's use in concrete inlays as well as
in construction of new low-volume roads.
Government Digest, April 2005
Wireless provider: new maturity system
To develop a specification for concrete maturity, the Michigan Department of Transportation (MDOT) sought a suitable project to test the use of a wireless concrete maturity monitoring system (CMMS).
The article describes the testing that took place on the site at the Grand River Avenue reconstruction project. The project involved removing and replacing an existing concrete pavement. The CMMS provided good concrete strength-gain results on the project, was easy to use and became a valuable tool for the reconstruction process. More information about this project from: http://www.tmemag.com/lm.cfm/tm030511
Roads and Bridges, March 2005
Something uncommon: new admixtures, supplementary materials lead to incompatibility
As more ingredients are added to the concrete mix, unexpected problems can arise due to interactions between the materials.
The article emphasises the importance of making trial mixes and to expose the concrete to similar temperatures or weather conditions tha are likely to arise on site. The importance of following manufacturers' recommendations carefully is also highlighted as is the value of keeping good records and retaining samples of the materials used to "help the detectives" if the need arises. More information from http://www.roadsbridges.com/lm.cfm/rb010509
Roads and Bridges, January 2005
Pulling the string
On a recent project,Belgian company Betonac, were faced with completing 10,3 miles of new roadway on a freeway carrying 57 000 vehicles a day within 126 days. Penalties were $50 000 per day of overrun. The article describes the measures they implemented to ensure the success of the project. More information from: http://www.roadsbridges.com/lm.cfm/rb100405
Roads and Bridges October 2004 |
