Grantee Research Project Results
Final Report: Innovative Approaches To Enhance the Structural Performance of Recycled Plastic Lumber (RPL)
EPA Contract Number: 68D99047Title: Innovative Approaches To Enhance the Structural Performance of Recycled Plastic Lumber (RPL)
Investigators: Krishnaswamy, Prabhat
Small Business: Engineering Mechanics Corporation of Columbus (EMC2)
EPA Contact:
Phase: I
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $68,415
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , SBIR - Waste , Small Business Innovation Research (SBIR)
Description:
This project outlines an approach to overcome one of the main drawbacks of recycled plastic lumber (RPL) currently manufactured using post-consumer and/or post-industrial waste thermoplastics. Structural applications for RPL are currently limited by its low stiffness values as compared with competing materials such as wood. Therefore, in spite of its many advantages such as longer service life, lower maintenance requirements, rot and insect resistance, RPL has not been able to penetrate the residential decking, marine and waterfront boardwalks, or pedestrian bridge applications to any appreciable extent.The innovation proposed in this project is to enhance the structural properties of RPL by designing a composite sandwich structure using existing high-modulus reinforcement materials. Once the design and manufacturing hurdles are overcome using the approach outlined in this effort, RPL could compete with traditional materials based on its performance characteristics. Additionally, it would have the advantage of lower life-cycle costs and would create markets to divert large amount of post-consumer waste plastics from landfills to high-valued, durable products.
The goal of this project was therefore to assess the feasibility of developing a novel manufacturing technique for reinforced RPL and verifying that the new material does have the enhanced strength and stiffness required for structural uses.
Summary/Accomplishments (Outputs/Outcomes):
The work carried out in this project included evaluation of potential reinforcement materials that are commercially available that are compatible with RPL. Next, novel approaches to bond the reinforcement to the RPL were explored. Then, both samples specimens and full- length structural pieces were prepared successfully using the novel bonding technique. The full-length specimens were tested under flexure to determine the level of enhancement of the structural properties of the new material as compared to the unreinforced RPL. The reinforced novel material showed three times the stiffness and over twice the strength of conventional RPL. Simultaneously with the experimental effort, analytical methods were developed to predict the structural characteristics of the reinforced RPL in a variety of loading configurations. The analytical predictions were then compared to the experimental data for verification of the methodology. These predictions showed excellent agreement between the experimental data and the analysis method developed. The analysis tools may also be used for developing design methodology for using the reinforced RPL in structural applications such as commercial decks, boardwalks, platforms, pedestrian bridges, etc.The success of this project will increase the markets for RPL significantly. The results anticipated in Phase II of this project is to develop novel designs, establish manufacturing and processing requirements, and fabricate prototypes of reinforced recycled plastic lumber. The new product is expected to retain all the advantages of the polymer and with significantly enhanced structural properties especially in flexure (bending). These enhanced properties would allow the new product to compete with traditional materials such as wood. Commercial applications for this reinforced RPL would include residential decking, marine and waterfront structures such as boardwalks, pedestrian bridges, and sheet pilings on docks and piers.
Conclusions:
The major conclusion of this work is that the concept of developing structural RPL by using high modulus reinforcement is both technically feasible and commercially viable.The manufacturing process to be developed in the project is anticipated to be cost-competitive and not involve significant capital expenditure compared with existing manufacturing technologies for RPL. The superior performance of the new RPL, coupled with lower life-cycle costs are expected to provide significant penetration into the $600 to $800 million commercial markets listed above.
Supplemental Keywords:
marine-applications, thermoplastic-composites, recycled plastic lumber, structural-joists, bonding, composites, decks, boardwalks, platforms, pedestrian-bridges., Economic, Social, & Behavioral Science Research Program, Scientific Discipline, Waste, Sustainable Industry/Business, cleaner production/pollution prevention, Municipal, Chemistry, Technology for Sustainable Environment, New/Innovative technologies, Engineering, Market mechanisms, green products, alternative materials, hazardous waste, polymers, recycling, plastic, recycled plastic lumber (RPL), innovative technology, plasticsThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.