From Waste to Wow: The Science of Fly Ash

fly ash TruExterior Siding & Trim

The use of fly ash as the primary component in Boral TruExterior products is about more than sustainability: Fly ash is what helps make TruExterior a high-performing, dimensionally stable, long-lasting product for a range of exterior applications.

Scientists and researchers in Boral’s Innovation Factory, which takes its physical form at a laboratory in San Antonio called the Discovery Center, spent years developing Boral TruExterior, including seeking the ideal raw material that would provide the look of wood with properties superior to not only natural products but what was available in manmade products.

The answer lay in fly ash, a byproduct of coal-combustion power generation that typically is sent to the landfill but in recent years has been discovered as a beneficial material for products including brick and concrete. Our scientists discovered a number of properties that contributed to fly ash being the ideal raw material.

Ideal Attributes
First, fly ash offers an ideal shape and size for balancing inexpensive inorganic material with expensive polymer adhesives. When manufacturers create the base material for their product, which for siding is a mixture that flows into molds or is extruded, they typically combine several ingredients, one or more of which is a glue or resin to hold everything together and fill in the “gaps” between the ingredient particles. In the case of TruExterior, fly ash is bound with a polymer. Ideally, formulations use as much inorganic material as possible, and therefore less polymer filling in the gaps, to keep costs down. Fly ash is ideal because it is spherically shaped and comes in several particle sizes. The spherical shape, rare in natural materials available in such abundance, exposes less surface areas for a given volume to be covered by a polymer. And with many different particle sizes, smaller fly ash particles will fill in the gaps between larger particles, much like if you poured sand into a jar of pebbles. Both of these properties mean less polymer is needed to fill the space and coat the particles.

fly ash TruExterior Siding & Trim
Fly ash under the microscope reveals its unique spherical shape.

The spherical shape also helps the material flow more easily.

From a performance standpoint, fly ash material is inert and inorganic. And because it is stable, it doesn’t react significantly with the environment, which is what helps TruExterior Siding & Trim remain dimensionally stable amid changes in moisture and temperature.

The scientists in the Innovation Factory were able to harness these discoveries and create a completely new category of building products—poly-ash. The resulting siding and trim products in the TruExterior family offer the look and workability of wood, while offering exceptional durability; resistance to cracking, rotting, splitting, and insects; and a high level of dimensional stability during periods of moisture and temperature change.

Finally, the use of fly ash does offer an important sustainability story: Seventy percent of TruExterior products use the recycled material, which would otherwise be bound for the landfill.

To learn more about the benefits of TruExterior Siding & Trim, click here.

LEAN Principles That Increase Efficiency

LEAN principles shadow board

The first thing you see when you enter the Boral Discovery Center in San Antonio, Texas, is what you can’t see—no clutter, no chaos, no extraneous noise. Because while nearly 30 people, including scientists, engineers, and support staff, work throughout the facility’s labs with numerous machines, hundreds of materials, and thousands of samples, a concentrated focus on safety and efficiency guides each step.

Assisting in those efforts is a facility-wide adherence to LEAN principles, much like you would find at some manufacturing plants.

“We are a lab with many, many projects and many samples,” notes Sarah Fortenberry, a Discovery Center research technician who also leads the facility’s LEAN programs. “So you have to manage not only the individual projects as well as the amount of materials coming in and going out. LEAN principles help us do that.”

Fortenberry notes that following LEAN guidelines also is key to maintaining a safe, healthy environment.

Here are a few of the LEAN tools the Discovery Center has implemented:

• Shadow Board: In areas with tools and equipment, storage areas are outlined and labeled, as shown in this photo. This includes everything from duct tape rolls to a hammer to extension cords. “There’s no wasted time trying to find an item,” Fortenberry notes. “It’s labeled, it’s where it should be.”LEAN principles shadow board The 5 S’s:
Sort: Frequently determine what you actually use and get rid of the rest. This helps keep work areas clutter-free and safe.

Set in order: Label everything and where it goes. The most important items should be the closest.

Shine: Keep work areas clean.

Standardize: Have a standard method for tools and equipment. Everything is labeled—every tool, every shelf, every drawer. This also pertains to samples, which ensures every test is tracked and identifiable. The process of managing samples is the primary reason that LEAN is essential at the Discovery Center.

Sustain: Establish how you keep the workplace clean and a cleaning schedule.

• 3C Board: The three Cs stand for Concern, Cause, Countermeasure. In each work area, the team has a 3C board. If something is wrong in the area, it goes up on the board, what’s causing the problem, and, eventually, what is being done to fix the problem.

• Total Productive Maintenance: Broken machines lead to costly downtime, so each machine has a list of maintenance steps needed to keep it running properly.

• 5S Fridays: At the end of every Friday, the team convenes to address problems on 3C boards. “We work as a team to get to and maintain a sustaining level of production,” Fortenberry notes.

• Kaizen: Kaizen is Japanese for “continual improvement.” The team hosts kaizen events in which they visit areas of the lab and track team members’ steps to see where there is wasted movement and how those steps can be consolidated. Bringing in team members who don’t work in that area provides a fresh perspective and out-of-the-box thinking.

“It’s made us more of a team, working as a group to improve our areas,” Fortenberry says. “Through the kaizen events and 5S Fridays, we can do something in a short period of time that would take someone weeks to do alone.”

The Science Behind TruExterior Siding & Trim: Thermal Testing

The creation of TruExterior Siding & Trim, with its industry-leading combination of performance and aesthetics, was the result of years of research, development, and testing. Today, that work continues at Boral’s Discovery Center in San Antonio, Texas, where chemists, engineers, and other scientists are continually studying existing products while innovating to uncover the next big thing in building materials.

For example, to ensure TruExterior performs as promised in both cold and hot climates, our scientists studied (and studied and studied) the product’s reaction to thermal extremes using several high-tech machines. These machines include:

• Thermal Gravimetric Analysis (TGA): This machine decomposes a material thermally. As the machine ramps up the heat, scientists monitor the material’s weight as its organic compounds break down, either producing or consuming gases. From the weight change and temperature, the active reaction can be extrapolated. For the end-user, this ensures a siding product won’t produce toxic gases or other hazardous compounds in extreme temperature situations, such as fires.
TruExterior Siding & Trim Thermochemical analysis

• Calorimeter: Similar to monitoring calories in food, this machine tracks the energy of chemical reactions. By understanding the processes involved in the formation of a material, scientists and engineers can optimize them to create the best possible finished products at competitive prices.

Calorimeter Siding

• Thermochemical Analysis: This machine observes how a material reacts under thermal stress by heating the material up and cooling it down. Our scientists use this machine to calculate a material’s coefficient of thermal expansion (CTE), i.e., how much it expands and contracts in the heat and the cold. This test was essential in the development of TruExterior, which experiences very little thermal expansion and contraction. thermal-gravimetric-analysis

• Differential Scanning Calorimeter (DSC): This machine is used to study what happens to polymeric materials as they are cooled and heated. By tracking changes in heat rate as energy is applied, the heat capacity, glass transition temperature, heat of melting, percent crystallinity, and other properties can be evaluated. These are carefully controlled to create an end-product that won’t adversely react under heat or cold.

  • differential-scanning-calorimeter

Ready to put our efforts to the test? Request a sample of TruExterior Siding & Trim here.