engineering

Rubberized asphalt

Rubberized asphalt is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rubberized asphalt rather than just read about it. In short: Rubberized asphalt concrete (RAC), also known as asphalt rubber or just rubberized asphalt, is noise reducing pavement material that consists of regular asphalt concrete mixed with crumb rubber made from recycled tires. Asphalt rubber is the largest single market for ground rubber in the United States, consuming an estimated 220,000,000 pounds (100,000,000 kg), or approximately 12 million tires annually.

Key takeaways

Rubberized asphalt belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Rubberized asphalt to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Rubberized asphalt from memory before moving on to harder problems.

Reference excerpt

Rubberized asphalt concrete (RAC), also known as asphalt rubber or just rubberized asphalt, is noise reducing pavement material that consists of regular asphalt concrete mixed with crumb rubber made from recycled tires. Asphalt rubber is the largest single market for ground rubber in the United States, consuming an estimated 220,000,000 pounds (100,000,000 kg), or approximately 12 million tires annually. Use of rubberized asphalt as a pavement material was pioneered by the city of Phoenix, Arizona in the 1960s because of its high durability. Since then it has garnered interest for its ability to reduce road noise. In 2003 the Arizona Department of Transportation began a three-year, $34-million Quiet Pavement Pilot Program, in cooperation with the Federal Highway Administration to determine if sound walls can be replaced by rubberized asphalt to reduce noise alongside highways. After about one year it was determined that asphalt rubber overlays resulted in up to 12 decibels of in road noise reduction, with a typical reduction of 7 to 9 decibels. Arizona has been the leader in using rubberized asphalt, but California, Florida, Texas, and South Carolina are also using asphalt rubber. Tests are currently underway in other parts of the United States to determine the durability of rubberized asphalt in northern climates, including a 1.3 mile stretch of Interstate 405 in Bellevue and Kirkland, Washington and a handful of local roads in the city of Colorado Springs, Colorado. In 2012, the State of Georgia issued a specification for the use of rubber-modified asphalt as a replacement for polymer-modified asphalt. In Belgium, tests in the ring of Brussel and in the F1 circuit of Francorchamp (see the film by Jean-Marie Piquint Rubberized Asphalt for Esso Belgium). Two quality control requirements are necessary when using asphalt rubber: (a) crumb rubber tends to separate and settle down in the asphalt cement and therefore asphalt rubber needs to be agitated continuously to keep the rubber particles in suspension and (b) crumb rubber is prone to degradation (devulcanization and depolymerization) and thus lose its elasticity if asphalt rubber is maintained at high temperatures for more than 6–8 hours. This means asphalt rubber must be used within 8 hours after production.

Porous Elastic Road Surfaces Porous Elastic Road Surfaces (PERS) or poroelastic road surfaces improve RAC by incorporating voids and channels, making the pavement porous and further reducing traffic noise.

References

External links Arizona Department of Transportation Quiet Pavement Pilot Program Asphalt Rubber Usage Guide, from California Department of Transportation

Worked examples

Example 1 — a first encounter with Rubberized asphalt

Start with the simplest possible case. Write down what Rubberized asphalt claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rubberized asphalt before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rubberized asphalt ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rubberized asphalt

In research: Rubberized asphalt appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Rubberized asphalt in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Rubberized asphalt is common in secondary-school and first-year university syllabi. It links to neighbouring topics Asphalt, Concrete, Pavements, so understanding it makes those chapters shorter.
In everyday life: Look for Rubberized asphalt outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rubberized asphalt in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rubberized asphalt means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Rubberized asphalt out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Rubberized asphalt in simple terms?

Why does Rubberized asphalt matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rubberized asphalt?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rubberized asphalt.