Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ASU researcher puts recalled Firestone tires to good use

26.07.2002


New field studies produce environment-friendly results

An Arizona State University researcher is making good use of some of the 14 million Firestone tires that were recalled two years ago. The tires were used on Ford Explorers and recalled after reports of tread separation. How to dispose of all those used tires without causing serious environmental hazards once had state officials scratching their heads, but Civil and Environmental Engineering Professor Han Zhu believes has the answer. Zhu says adding a small amount of the inexpensive crumb rubber to fresh concrete can improve strength and durability. Crumb rubber is the end result of grinding used tires into one-millimeter chunks. One tire produces about 10 pounds of crumb rubber and sells commercially for less than 20-cents per pound.

While Zhu is not the first researcher to experiment with adding the tire bits to Portland cement concrete or PCC -- the technology has been around for 30 years -- he does own rights for the first "real world" application. A patent is pending on the ASU process for making rubberized concrete.

Arizona is one of the leading states for using crumb rubber in pavement, said Zhu. He began to explore uses for crumb rubber in 1998 with a grant from Arizona Department of Environmental Quality. His research, however came to a screeching halt soon after because he could not find a natural environment as an experimental site, a critical step in testing new materials prior to certification.

While rubberized asphalt has been used for decades on roadways, rubberized concrete is a technology infant. The researcher said in the beginning few people were interested in using a new material because there was no guarantee of success.

In February 1999, Zhu personally added 200 pounds of crumb rubber to the concrete mixture being prepared for a test site on the campus of Arizona State University in Tempe. He says the ratio of crumb rubber added to the mixture equated to about 8 percent of the cement weight. Since that time, dozens of residential and commercial rubberized concrete sites have been poured, monitored and deemed successful, including some extreme cold weather applications. A field demonstration project using the recalled Firestone tires was poured last fall as part of a frontage road along Interstate 17, near Cordes Junction, Arizona. Crumb rubber concrete is also being tested for noise control along a busy freeway in Scottsdale, Arizona.

Prior to Zhu’s research, similar lab studies were not encouraging for the waste product. Earlier research showed that adding crumb rubber to concrete would lower the compressive strength, the major criterion used in designing PCC.

However, Zhu’s study showed adding the crumb rubber into PCC actually produced several benefits that would compensate for the loss in compressive strength, particularly for projects that are not considered loadbearing. These benefits include reductions in thermal expansion, also known in Arizona as Summer Fatigue, along with reductions in drying shrinkage and brittleness. The recycled rubber also shows promise in ending the crumbling associated with freeze and thaw damage in colder climates.

Zhu says these benefits alone significantly improve the overall durability and serviceability of PCC. More recently, the researcher made new advances by boosting the compressive strength levels of crumb rubber PCC to specifications by simply adding a small amount of gypsum to the mix.

According to the Arizona Cement Association, within the Phoenix metro area some 12,000 cubic-yards of PCC are produced each day. By conservative estimates, if just 20 pounds of crumb rubber per cubic yard of fresh PCC were added, all 5 million scrap tires produced annually in Arizona could be recycled into stronger and more pliable PCC for use in sidewalks, parking lots and concrete floors. Crumb rubber concrete appears to avoid cracking and flaking common to traditional concrete.

"Scrap rubber is a wonderful building tool that deserves public attention. As more crumb rubber PCC structures are built, the benefits that this technology can bring to our communities will become increasingly apparent," Zhu said.

Lynette Summerill | EurekAlert

More articles from Transportation and Logistics:

nachricht New players, standardization and digitalization for more rail freight transport
16.07.2018 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht A helping (Sens)Hand
11.04.2018 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

All articles from Transportation and Logistics >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>