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 Variable speed limits could reduce crashes, ease congestion in highway work zones
07.06.2017 | University of Missouri-Columbia

nachricht Experiments show that a few self-driving cars can dramatically improve traffic flow
10.05.2017 | University of Illinois College of Engineering

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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>