Grantee Research Project Results
Final Report: Husk-to-Home: A Sustainable Building Material for the Philippines
EPA Grant Number: SV836952Title: Husk-to-Home: A Sustainable Building Material for the Philippines
Investigators: Tam, Kawai , Rust, Michael , Siahon, Jannette , Truong, Katherine , Sakaguchi, Keila , Martinez, Dianna-Kristina , Fischer, Isabelle , Sharma, Aneesh , Lamas, Jacqueline
Institution: University of California - Riverside
EPA Project Officer: Page, Angela
Phase: II
Project Period: February 1, 2017 through January 31, 2019 (Extended to January 31, 2023)
Project Amount: $74,838
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2016) Recipients Lists
Research Category: P3 Awards , Sustainable and Healthy Communities , P3 Challenge Area - Sustainable and Healthy Communities
Objective:
Husk-to-Home (H2H) is a project team that began with the goal of creating a sustainable and easily accessible material that could be used in emergency housing relief for those affected by yearly typhoons and earthquakes in the Philippines, while mitigating pollution in the environment. In discussions with the Non-Governmental Organization (NGO) in the Philippines, the overall objective of the research pivoted to produce predominantly house siding materials with potential applications in other markets in the developed world, and the specific project objectives focused on the characterization and elongation of the boards.
Summary/Accomplishments (Outputs/Outcomes):
Between the years 2017 to 2023, the Husk-to-Home team researched to produce sustainable medium-density particle boards from waste products such as rice husk, rice straw, and high-density polyethylene (HDPE). Throughout this project period, H2H members conducted various tests according to American Society for Testing and Materials (ASTM) standards to prove the durability and competitive qualities of the board compared to current manufacturers in the market. The boards can be produced in various dimensions and densities and layered, similar to plywood, allowing for a broader range of use. Overall, the boards have proven durable, sustainable, and marketable for multiple applications.
The project was also used as an educational conduit through several capstone senior design courses, dissemination of information to the campus and public through events in association with the UCR Student Chapters of Engineers Without Borders, American Institute of Chemical Engineers, and the Society of Women Engineers, and to the business community through the Research and Economic Development division at UCR.
In 2017, Husk-to-Home produced 9” x 9” x ½” particle boards and conducted ASTM standard tests to examine the material's durability for use as house siding. These tests included the three-point bend test, compression test, screw test, and absorption and soak test. The data showed that the boards had competitive mechanical properties compared to commercial boards.
In 2018, further testing was done by an independent lab for nail head pull-through, moisture content, and Janka ball hardness testing, with positive results for Husk-to-Home's board. A separate independent testing lab conducted accelerated aging tests on the prototype siding, which showed that it could withstand at least 25 years of simulated weathering under harsh conditions. In termite testing, the H2H board sustained almost no damage compared to the control board, pine wood, which proved it to be termite resistant.
In 2019, primary objectives included the development of elongation methods for the boards to expand applicable uses, evaluating the effects of natural UV rays upon the boards, and assessing the recyclability of the board materials for sustainability purposes. To elongate the board, a viable option involved the design of a board mold to produce boards with interlocking geometry on two sides; the boards could then be put together like puzzle pieces and placed back in the heat press to create an elongated board. The team designed an in-house UV testing apparatus and a standard operating procedure (SOP) following the ASTM-G154 protocol for simulating outdoor UV effects. Efforts to study the recyclability of the boards were hindered by the lack of efficient methods to pulverize the pressed boards into a powder. Preliminary results were achieved by a time-consuming process of shaving the boards into thin strips and regrinding the strips into a powder. This board powder was then combined with a new mixture to create the recycled board recipe and pressed according to the original procedure. It was found that the recycled board was only 75% as strong as the original board.
In 2020, due to the COVID-19 pandemic, the focus shifted to board expansion, characterization, and large-scale manufacturing possibilities. The team was split between those who were allowed in the lab due to COVID-19 restrictions and those who did remote work. Those who went into the lab tested the recyclability of boards and pressed 9” x 9” boards for UV, mold, and flame testing. Those who worked remotely wrote standard operating procedures, designed new board molds, and reached out to manufacturers to ask about manufacturing possibilities. In mold growth susceptibility tests, the H2H board experienced notable mold coverage with an average of 51.6% of the overall surface area on one side of the board, while the similarly exposed cedar boards had an average of 3.5%. For the control experiments, H2H control boards saw no mold growth, but small amounts of mold were seen growing on all three of the control cedar boards. The H2H boards were susceptible to mold growth when moist, so the team conducted additional mold testing in 2021 and discovered a clear UV-protectant wood varnish was needed to prevent mold growth. The results showed that UV-protectant varnish offers multiple benefits for the boards, including UV protection and mold resistance. It was highly recommended that H2H boards be coated with UV protectant paint or varnish before they are used in an outdoor application.
In 2021 and 2022, the Husk-to-Home team’s objective was to prepare for burn/flame testing, expand board production, and analyze UV test results. A mock-up of a typical household wall structure was designed according to ASTM E119 specifications and was sent to a laboratory in New York for fire testing. The Husk-to-Home test wall was smaller than the standard 10’ x 10’ condition, so the board could not be tested for load-bearing capabilities according to the ASTM method. Without the capability to create a 10’ x 10’ wall, the ASTM wall size was adjusted to be 3’ x 3’ as recommended by the certified fire testing facility. To expand board production to create the fire testing wall, the Husk-to-Home team worked with the University of California Riverside’s (UCR) Machine Shop to design a tight tolerance mold design that required no welding and thus was easier to manufacture. A total of three new molds were created, and production increased to three to six 9” x 9” uniform boards per day. With multiple molds, the H2H team could let the boards completely cool in the molds under constant pressure resulting in more uniform boards. The failure criteria in the flame resistance tests included the following: have all thermocouples reach an average of 250°F, have one thermocouple exceed 325°F, or have the flames burn through the board. The structural wall with the H2H board was found to be fire-resistant after an hour of testing because it could burn for an hour without completely burning through or meeting the other performance failure criteria.
By 2023, fire testing was completed, and the Husk-to-Home team’s new objective was to produce a ⅜” plywood using the original rice husk composite recipe. The team manufactured ¼” thick boards to conserve materials and labor for the recyclability testing, and in the effort to scale down to ⅛” to make the plywood configuration. The new ¼” boards were tensile, flexure, and compression tested using an Instron machine. Because the ¼” board showed some inconsistency in board composition, leading to uneven strength, additional board mixture material was added. The results of the compression, tensile and flexural tests determined that boards with 10% more material in comparison to the original mass was optimal.
In addition, eighteen ⅛” Husk-to-Home boards were sent to a facility that presses and produces plywood. Two types of plywood boards were made, one using a water-based adhesive, ISOSET WD3-A322/CX-47, and the other with polyurethane adhesive, ISOGRIP 3030D. The ⅜” plywood was cut into 1” x 1” and 1” x 3” strips and tested with an Instron machine. On average, the boards bonded together with the polyurethane adhesive had the overall highest average compressive strength and maximum load. When the water-based adhesive outperformed the polyurethane, the difference was marginal. When the polyurethane outperformed the water-based adhesive, the difference was more significant. The data suggests the polyurethane adhesive is better overall.
An interlock mold was designed in an attempt to elongate the boards. This mold would provide the ability to create a board up to 12” x 34” dimensions. The dovetailing feature along the edge of the mold would allow the boards to connect, similar to a puzzle piece. The mold underwent several iterations and was manufactured by the UCR machine shop. Now, three different assembly options allow the production of ⅛”, ¼”, and ½” thick interlocking boards.
Conclusions:
The Husk-to-Home team was successfully able to characterize and manufacture boards with various thicknesses and an interlocking design. The H2H boards proved to be a viable solution, especially with the addition of the varnish, as they proved to be termite-resistant, flame-resistant, and comparable to commercial particle boards. In the future, the team plans to use the plywood boards for broader applications, such as creating a skateboard. Overall, the H2H boards are sustainable, high-quality products that meet their original goals and have versatile uses.
Since the inception of the P3 project, thirty-five undergraduate students and three graduate students have conducted research on the project. This project enabled multidisciplinary collaboration between six departments at UCR including Chemical Engineering, Environmental Engineering, Mechanical Engineering, Materials Science Engineering, Business Administration, and Economics. The P3 project contributed to five capstone senior design courses which fulfilled requirements in the Chemical, Environmental, Materials Science, and Mechanical Engineering departments, and 1 honors thesis in the Business Administration department.
Journal Articles:
No journal articles submitted with this report: View all 3 publications for this projectSupplemental Keywords:
sustainable materials, recyclable materials, rice husk, rice straw, recyclable, flexural strength, humidity, termites, water-resistant, composite, building material, green engineering, formaldehyde-free, extrusion, plastic, compressibility, machinability, economical, shelter, eco-friendly, tannin, tensile strength, particle board, cost-efficientRelevant Websites:
Progress and Final Reports:
Original AbstractP3 Phase I:
Rice Husk: A Sustainable Building Material for the Philippines | Final ReportThe 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.
Project Research Results
- 2021 Progress Report
- 2020 Progress Report
- 2019 Progress Report
- 2018 Progress Report
- 2017 Progress Report
- Original Abstract
- P3 Phase I | Final Report