From Trash to Major Interstate Repair

How bottles and jars are changing the face of civil engineering projects and the testing needs behind it all.

How many tons of recycled glass would it take to build an emergency support for one of the busiest four-lane highways in the world? I honestly wouldn’t have a clue but I know someone that does.

Theresa Andrejack Loux is the Chief Technical Officer for AERO Aggregates, a Pennsylvania-based company with a second plant in Florida and another in California coming on stream later this year. The company takes your empty bottles and jars from recycling plants and landfill sites, turning them into an eco-friendly aggregate for use in a myriad of civil engineering applications.

Foamed Glass Aggregate (FGA) has been used as backfill in numerous projects, primarily where the soil underneath is soft and compressible and cannot support too much excess weight, such as an overnight parking apron for airplanes at Philadelphia International Airport.

The Foamed Glass Aggregate weighs around one sixth of regular soil - Tinius Olsen

Fig 1.

The Foamed Glass Aggregate weighs around one sixth of regular soil

In fact, it is so effective that it was being used to build up the damaged section of the Cottman Avenue exit ramp on the I-95 interstate on the outskirts of Philadelphia, which collapsed following a tanker truck fire in June this year. A staggering 215,000 cubic feet FGA was used to support a temporary, six-lane highway while contractors rebuild the actual bridge.

“FGA is absolutely ideal for this project as it only weighs around one sixth of regular soil due to it being full of air bubbles. In the case of I-95, this will help protect the ageing sewage lines running underneath the structure as they simply couldn’t withstand the weight of another 20ft of traditional soil material,” said Theresa.

Theresa Andrejack using Tinius Olsen equipment and Horizon software to test the aggregate

Fig 2.

Theresa Andrejack using Tinius Olsen equipment and Horizon software to test the aggregate

“It was an awful accident and has caused huge inconvenience to everyone in the Philadelphia area so we’re just delighted we can help and get things moving again extremely quickly.”

The manufacturing process of the aggregate starts with cleaning the glass and then grinding it into a powder and subjecting it to a three-phase cleaning and filtering procedure. Workers then add a proprietary, mineral-based foaming agent and heat the powder in a kiln at 1,650 degrees Fahrenheit.

The material emerges from the kiln looking like a long, gray sheet of cake. Upon cooling, the material cracks into gravel-like pieces.

“We aim for the bulk density of our standard product to not be any heavier than 15 pounds per cubic foot, which corresponds to about 240 kilograms per cubic meter. We follow ASTM C29 standard for this type of bulk density measurement.”

“The other test that we run on a daily basis is a confined compressive strength test, which is what we use our Tinius Olsen 150ST machines for in each of our Philadelphia and Florida plants, with one on order for California. The company’s experience and input has been invaluable in developing the product from the get go and being a local company to ourselves has been an even bigger bonus.”

“The test method used for these compressive tests is EN 1097-11 although we’ve started down the road of trying to get a similar test standard in place at ASTM, which will obviously take some time.”

But where does all the required glass come from?

“Most communities do have some type of recycling program in place. Sometimes the trend in recent years has been that some communities have dropped glass from the materials that they’re collecting through single-stream programs but certainly there’s still many programs that do collect glass.”

“We work with recycling entities that are local to our plants to source the glass product that we need. We generally take lower-value glass because it’s the mixed color, the smaller pieces that generally can’t be used by a bottling operation or even a fiberglass plant. The glass product that we use generally goes to landfill if we don’t take it”

“When our California plant opens later this year, we will have the capacity to divert over 500 million bottles per year from landfill.”

It’s been an amazing journey for Aero Aggregates and a perfect example of how materials testing is vital to the development of any exciting new product. This is especially true with FGA, which can make such a huge difference to everyday life and Tinius Olsen looks forward to helping develop this material even further in the future.

Oh and it took the equivalent of 6.5 million glass bottles in FGA to build the supporting structure for the I-95 emergency repair………..


Useful links

Civil Engineering Testers

Compressive Strength Test

Aggregate Test

Soil Test

Model 150ST

Building & Construction

Sustainable Alternatives Gain Validation Through Materials Testing

The past few years have shown us that the world around us is finite and fragile. And we all play a part in its sustainability.  There has been a push across several industries to develop inventive, forward-looking products and technologies, while maintaining a better balance with the environment for long-term global health.

With innovation comes the unknown. Will a newly developed material stand up to the defined ASTM or ISO standards or will the use of a different material in an existing application meet the required industry standard benchmarks?  Standards exist to ensure product safety and quality, which is all for the benefit and protection of the end user.

Confidence in Material Innovations

As an industry, we are tasked with maintaining a level of confidence in the products and solutions being delivered, and standards are an important aspect of that. There are many promising examples of sustainable products that incorporate recyclable or biodegradable materials and also support an eco-friendly environment.  But to be able to confidently put these innovations into the mainstream, companies still rely on materials testing to known industry standards and specifications.

Material testing provides the insight to gauge the useability of certain materials and products in specific environments. And in the world of eco-friendly material innovation, it has helped lay the groundwork to develop solutions beyond just delivery of a product, but also to help combat climate change, to increase types and quantities of materials that can be recycled, and ultimately open doors to innovations that are solving some real-world challenges.

Recycled Glass Aggregate

The collapse of I-95 in Philadelphia, PA seemed, at first, catastrophic. Initial calculations framed the road closure in years, then possibly over several months.  So who would have thought that in a mere few weeks, this massive roadway connecting a large swath of the eastern United States would be up and running after such an epic event, using a sustainable material made from glass.

Recycled glass aggregate is not new. Formed by crushing glass into a powder, blending it with a foamy slurry, heating it and then breaking it into briquettes, the crushed aggregate is used in a number of construction applications, including as backfill or in roller applications.  The size, shape, density and strength of the aggregate all affect its long-term performance in pavement and structures.

Testing of the ultra-lightweight foamed aggregate is critical to prove its efficacy and ensure it has the strength needed to bear the weight and force of heavy-duty construction. It also confirms that the aggregate is composed of a good mix of chemicals and materials that can compact to and withstand a certain force. Thanks to testing performed using Tinius Olsen equipment, the company developing the aggregate already had the results and data to know this aggregate could serve as the backfill for the temporary lanes constructed along the highway corridor.

Testing of the aggregate is carried out with Tinius Olsen equipment

Fig 1: Testing of the aggregate is carried out with Tinius Olsen equipment.

Sustainable Wool Rope

Seaweed farming itself is not only a sustainable source for fertilizer, bio-ethanol and livestock feed, but it helps negate carbon and nitrogen levels in the ocean as well as provides a healthy ecosystem for marine life. So the fact that non-recyclable, everlasting polypropylene rope is laid on the sea floor to grow the harvested seaweed counterbalances the environmentally-friendly aspects of growing a renewable resource. And this plastic rope is washing up on coastlines across the globe, rubbing against rocks, resulting in a hard plastic crust coating the coastlines.

But what if the rope was made of biodegradable wool that itself is sustainable and renewable.  Would its physical properties still hold up as needed in the corrosive saltwater environment? Tinius Olsen is helping to answer this question.

Manufactured in a range of diameters, from small lengths to full coils, all of the wool rope currently produced is from local farms and craftspeople in the United Kingdom. But this paradigm shift for seaweed farming needs validation and is being accomplished through materials testing.  By relying on proven equipment Tinius Olsen is helping to identify the proper breaking strain as well as design the special grips needed to hold the rope for proper testing.

The sustainable rope is used to farm seaweed and shellfish

Fig 2: The sustainable rope is used to farm seaweed and shellfish

Testing of Eco-friendly Innovations

In the world of materials testing, manufacturers turn to industry standards to enable them to validate, qualify and prove the viability of their products and raw materials.  For materials pushing the envelope of what is known and acceptable, testing to a defined set of compliance levels becomes even more critically important.

Developing sustainable material alternatives and bringing them to market is no small feat. Testing validation is just one aspect of this process. Also of importance is a partner invested in the success of innovative product development and who has the technical knowledge and pedigree to deliver quality testing equipment to validate your product innovations.

Elevated Temperature Testing Validates Innovation in Additive-based Superalloy Manufacturing

Commonly used in extreme environments, such as in the aerospace, industrial and power generation markets, superalloys are a class of high-performance alloys with impressive mechanical strength as well as resistance to thermal creep and corrosion at high temperatures.  Those in the materials science and engineering industries continue to develop increased performance capabilities and seek out new applications for these advanced materials.

Although used for decades, this type of material still requires specialized manufacturing techniques and produces a lot of wasted material, driving up costs in production. Additive manufacturing, which involves melting and fusing metal powders layer by layer, has emerged as a promising technique for producing the complex geometries of superalloy components as well as for reducing material waste during production.

Also known as 3D printing, this is still a relatively new, intricate process, and a deeper understanding of the performance and durability of the materials produced using this additive method is needed. (Figure 1)

Elevated Temperature Testing

Fig 1: The production of 3D printed high temperature superalloys is still a growing area, but elevated temperature testing can remove some of the unknowns in quality and reliability.

Studying Material Behavior
Those tasked with the production of superalloys have sought out new methods to further advance this additive manufacturing of superalloys and improve the performance and reliability of superalloy components in extreme environments. Answering the questions surrounding the mechanical behavior of these additively manufactured superalloys is a critical step in enabling this modern manufactured material to move beyond skepticism and play a critical role in high-performance applications. 

Elevated temperature mechanical testing has always played a key role in the development of new materials that need to withstand extreme conditions, and additive-based superalloys are no different. By subjecting materials to elevated temperatures and mechanical stress, researchers have been able to identify the strengths and weaknesses of different materials, which has allowed them to develop new materials as well as identify ones that are better suited to specific applications.

Playing a particularly important role in the additive manufacturing of superalloys, elevated temperature mechanical testing allows researchers to study the behavior of these materials by simulating the high-temperature, high-pressure environments are often found in real-world applications. (Figure 2)

Tinius Olsen Elevated temperature testing

Fig 2: Today’s elevated temperature testing environments are total systems, comprised of the frame, chamber, sensors, specimen holders and software to help manage and analyze system data.

Why Elevated Temperature Testing?

Insights gained into the material’s microstructure and deformation behavior under different conditions can help identify potential weaknesses or failure modes in the material and inform the development of improved manufacturing processes or material designs. Proper elevated temperature testing can answer significant questions that will provide better performance and efficiency in the application of superalloys produced using additive manufacturing techniques:

  • What are the effects of different heat treatments on the mechanical properties of additively manufactured superalloys?
  • How do different alloy compositions perform under these temperature and stress extremes?
  • What strengths and weaknesses do these materials exhibit and how can each be used in specific applications?
  • With access to more accurate, repeatable data, what improved predictions can be made about a material’s behavior under extreme conditions?

Testing Today’s Superalloys

Modern elevated mechanical testing methods make use of advanced instrumentation and control technology, such as high-temperature furnaces and specialized testing frame and software configurations capable of applying precise loads, strains and temperatures to the specimens under test.

The development of these more advanced testing equipment and techniques has enabled significantly improved accuracy and repeatability, resulting in more precise insight into material behavior under extreme conditions. This has led to an increased understanding of material behavior, with researchers gaining insights into the fundamental physics of material behavior. Ultimately, new materials with improved properties and new production techniques can confidently be brought to market.

Testing standards also play a critical role in the testing of superalloys, so it’s important to note some of the more common ones used in elevated temperature testing. These include ASTM E21, ASTM E139, ASTM E145, ASTM E220, ASTM E1457 and ISO 6892-2, all of which define the test parameters, measurements and results to precisely characterize the response of material to determine its strength, performance and ensure quality to prevent failure in use as well as make informed decisions in terms of which materials to use for a given application.

Elevated mechanical testing continues to evolve and improve with new developments in materials science and technology. This materials testing method has helped to improve the safety and reliability of many critical systems, such as aircraft engines and nuclear power plants. By understanding how materials behave under extreme conditions, engineers can design systems that are better able to withstand these conditions without failing or causing harm to people or the environment. When working with new, innovative materials, such as additive manufactured superalloys, confidence in the process is just as important as confidence in the material.