Grantee Research Project Results
Biobased Sandwich Panels for Construction ApplicationsEPA Grant Number: FP917165
Title: Biobased Sandwich Panels for Construction Applications
Investigators: Michel, Aaron Travis
Institution: Stanford University
EPA Project Officer: Zambrana, Jose
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010)
Research Category: Academic Fellowships , Fellowship - Science & Technology for Sustainability: Green Engineering/Building/Chemistry/Materials
Biobased composite materials made from polyhydroxybutyrate (PHB) and natural fibers have useful mechanical characteristics while in service, and can rapidly biodegrade after their useful life. This project aims to replace what is a primarily linear system of construction (i.e., raw materials to built systems to waste materials), by using resources that are easily sustainable, harvestable, or otherwise readily available and will biodegrade rapidly and completely in an anaerobic environment after their useful life. Sandwich panels constructed from biobased composite face sheets and an insulating core will be investigated with the objective of increasing structural efficiency and thermal resistance.
Resource consumption and waste production by the construction industry have motivated the investigation of innovative building materials. Biobased composites made from polyhydroxybutyrate (PHB) biopolymer and natural fibers have comparable mechanical properties to wood used in construction, and offer an alternative that requires less energy to produce, reduces landfill waste, and biodegrades anaerobically. This project examines efficient and effective uses for these biobased composites.
The technical challenge of this project is in balancing (1) the engineering of a low-density structural element with comparable mechanical and thermal properties to traditional construction materials, with (2) the engineering of a useful structural material that possesses excellent structural properties while in service but rapidly biodegrades after its useful life. This work will be accomplished by designing and evaluating structural sandwich panels made from PHB-natural fiber composite face sheets and biodegradable foam cores. The work will consist of the following tasks: (1) sandwich panel design using experimentally determined material constitutive models and finite element analysis (FEA); (2) characterization of biobased sandwich panel mechanical, thermal, and weathered properties; (3) manufacturing analysis of production techniques at varying scales (i.e., laboratory vs. commercial); (4) design for long-term performance and rapid post-use biodegradation; (5) construction application case study using a scale pilot project.Expected Results:
PHB-natural fiber biobased composite sandwich panels can be engineered to have comparable structural efficiency (i.e., strength/stiffness-to-weight ratio) and superior thermal performance to traditional construction materials, such as wood and engineered wood products. Long-term weathered panel performance will be improved by the addition of biodegradable chemical fiber modifications and sealants, while post-use anaerobic biodegradation will be accelerated by appropriate composite design and the selection of suitable environmental conditions (to be performed by others). A simplified design framework for engineering practitioners will be developed using classical composite theory, FEA analysis, and empirical test results. It is also expected that biobased sandwich panels can be manufactured using both lab and industrial scale hot presses, and that large-scale panel production is possible using the existing infrastructure for engineered wood products. Biobased composites and sandwich panels will be useful in many construction applications, such as formwork, scaffolding, lagging, paneling, flooring, and temporary housing.
Potential to Further Environmental/Human Health Protection
The broad impacts of this project include (1) the introduction of a construction material that is fully recyclable and producible globally; (2) a reduction in construction resource consumption and demolition waste disposal in landfills; and (3) a reduction in greenhouse gas emissions associated with the production and use of traditional building materials and from un-captured methane from landfills. This research will also address underprivileged and minority groups by employing materials that can be grown locally, reducing the financial and environmental burden of shipping and the inequality imposed by local material availability.
biobased, biocomposite, sandwich panel, SIP, natural fiber, construction, anaerobic biodegradation,