Abaca Fiber With Epoxy as A Retrofitting Material
This work deals with the investigation and viability of the composite abaca fiber and epoxy as a retrofitting material. When uniaxially loaded concrete is restrained from dilating laterally, it exhibits increased strength and axial deformation (De Lorenzis and Tepfers 2003). This behavior becomes useful for the strengthening of existing concrete structures in which higher axial load capacities are required, or for improving the seismic performance of deficient concrete structures. Confinement of axially loaded concrete members in existing structures is required when a change in use is expected or when there is a need to upgrade the structure to meet current design standards. In addition, after unusual overloading events (e.g., earthquakes), axially loaded members can suffer damage that increases the need of their retrofitting by means of confinement.1
This study also realizes the abundance of locally available natural fiber abaca in addressing the need for new reinforcing materials that are both cheap and environment-friendly. Abaca fiber is endemic in the Philippines and is considered as one of the strongest natural fibers. In recent years, abaca has shown promise as an energy - saving replacement for glass fibers in automobiles. For one, Mercedes- Benz is known to have used abaca fiber - reinforced polypropylene composite in automobile body parts while Daimler Chrysler used them in under floor protection of passenger cars. Recently, the DOST-ITDI developed a composite material that is a combination of abaca fibers and resin that can be used as roofing materials for the driver’s seat and sidecar of tricycles. It is a good substitute material for metals like stainless steel, galvanized iron, and others that are commonly used to make tricycle roofs and sidecars, and some automotive parts/components.2
To determine the viability of the composite as a retrofitting material, three variations of concrete specimens was compared to the other specimens. Five samples for each three variation of cylindrical concrete specimens namely the plain concrete cylinder specimen, the concrete cylinder specimen with epoxy and the concrete cylinder with the composite epoxy and abaca fiber. The concrete samples were wiped with dry cloth prior to application of epoxy. The epoxy was mixed in equal ratio for 5 minutes. A first coating of 262 grams of epoxy is applied by putty blade to the concrete sample resulting in an approximately 0.25 mm thick of epoxy. The fibers were then wound manually in a spiral manner in the concrete sample until the sample is covered with the fibers and before the epoxy dries. Then another application of 262 grams of epoxy was performed to sandwich the fibers between the layers of epoxy.The composite abaca fiber and epoxy was cured for 4 days prior to testing. With single factor analysis of variance, results showed a significant increase in the compressive strength of the samples with epoxy as compared to the plain concrete samples and the samples with the composite epoxy and abaca fiber as compared with the samples with epoxy.
Indexterms - Abaca fiber; Epoxy; Composite; Retrofitting.