Case Study: CARE Innovation Grant Advances Sustainable Composites

West Virginia University Achieves Breakthrough in Carpet Backing Reuse

testing grant recipients at work — *West Virginia University received a Cycle 1 Innovation & Design grant to study the inclusion of PC4 in fiber-reinforced plastic composites.*

In 2022, the Carpet America Recovery Effort (CARE) launched its first-ever Innovation & Design Grants to inspire creative, scalable solutions for post-consumer carpet (PCC) materials as well as more sustainable carpet manufacturing designs. One of the pioneering recipients was West Virginia University (WVU), which was awarded $100,000 to tackle one of the most underutilized PCC components — Post-Consumer Carpet Calcium Carbonate (PC4). WVU’s project proposed a novel way to recover and reuse this mineral filler in high-performance infrastructure materials, potentially transforming a burdensome waste stream into a valuable manufacturing resource.

The Project: Creating High-Value Use for Recycled PC4

The WVU research team, led by Dr. Rakesh Gupta, Dr. Hota GangaRao and Chao Zhang, focused on integrating PC4 into fiber-reinforced polymer (FRP) composites — materials widely used in construction, including bridges, utility poles and structural reinforcements. These composites typically rely on virgin fillers; the WVU project aimed to replace that virgin material with PC4 extracted from discarded carpet backing.

Key project goals included:

Characterizing the recovered PC4 for size, purity and surface condition.
Measuring and optimizing its effect on resin viscosity and mechanical strength.
Fabricating composite samples at the lab scale.
Collaborating with Bedford Reinforced Plastics (BRP) for industrial-scale pultrusion manufacturing.
Developing a business case to support widespread adoption.

“This simple idea has real impact: it helps save money, reduces waste and supports greener construction,” noted Zhang. “Reusing recycled (calcium carbonate) from carpet backing as a filler in FRP composites typically results in 9 to 73% lower production costs than virgin materials and lowers lifecycle CO₂ emissions, since mechanical recycling tends to consume less energy and generate about 30% less greenhouse gas emissions than producing virgin filler.”

Results: Technical Feasibility and Mechanical Performance

The WVU team achieved several breakthroughs:

Recycled PC4 could be used successfully in FRPs at up to 30% by weight, although 20% proved optimal for industrial applications.
At 20%, composites using recycled PC4 matched or closely approached the performance of virgin-filled composites across tensile, compression, shear and bending strength tests.
Optimal particle size distributions were identified to reduce resin viscosity to workable levels for manufacturing.
The study showed that recycled PC4 increased stiffness while maintaining acceptable levels of strength, making it suitable for many non-structural or semi-structural FRP uses.

Challenges: Impurities, Viscosity and Material Uniformity

The team encountered challenges common to post-consumer material reuse:

Recovered PC4 carried residual fibers and dirt that increased resin viscosity and affected workability.
The variability of recovered material required extensive sieving and particle characterization.
At higher filler concentrations (above 30%), viscosity became too high for processing and composite strength dropped.

To address these issues, the researchers used ultrasonic cleaning and fine sieving to remove fibers and standardize particle size. They also recommended a 20% filler threshold for pultrusion-based production to balance cost, quality and workability.

Successes: Innovation, Industry Engagement and Environmental Impact

This project marked a significant step forward in sustainable materials engineering:

It validated a scalable end-use for post-consumer carpet backing material —an innovation that had not been realized before.
It produced lab-scale and industry-ready FRP parts using recycled filler.
It engaged BRP, a commercial pultrusion company, in pilot testing for real-world adoption.
It advanced CARE’s mission by demonstrating a replicable pathway for diverting a key carpet waste stream from landfills.

Most importantly, the project showed that recycled PC4 when properly processed, could substitute for virgin material without sacrificing composite integrity—supporting a circular economy in both the carpet and construction industries.

“In the next phase, we plan to optimize how much of this fiber-filled material is added to the resin and fine-tune the production process,” said Zhang. “If successful, we could reuse 60 to 95 percent of the carpet waste, offering a practical, low-cost and sustainable alternative to traditional fillers.”

Funding and Collaboration
The project was funded by a $100,000 CARE Innovation and Design Grant, with a $25,000 in-kind cost share, including tuition support and pilot manufacturing costs from BRP. WVU’s Constructed Facilities Center provided the research infrastructure and testing capacity for the study.

Conclusion: Building a Greener Future
Through its innovative use of recycled materials, WVU’s project offers a glimpse into a future where PCC acts as a raw material for infrastructure solutions. As the project advances to full-scale manufacturing with BRP, it holds promise for reducing landfill dependency, lowering material costs and fostering new green jobs in California and beyond. CARE has funded a total of six Innovation and Design grant projects focused on higher value end uses for PCC, PCC tile reuse and recycling and industry circularity. CARE anticipates launching the next cycle of grants in November 2025. For more information, visit the CARE Grants page.

This is one of a series of case studies that illustrate the impact and logistics of grant funding on the carpet recycling industry in California.