Adherence of geopolymer and pultruded composite substrates: influence of adhesive type and surface treatment

Abstract

In the last years, the use of adhesive bonding is increasing as an alternative to traditional joining techniques due to their advantages such as ease of application, low weight and the good mechanical properties. To ensure good adherence between the substrates, adequate materials and surface treatment are required. The main objective of this work is to evaluate the adherence of epoxy and polyurethane adhesives between a pultruded composite material and a geopolymer. Two different surface treatments were evaluated: unidirectional abrasion (UA) and bidirectional abrasion (BA). Epoxy and polyurethane adhesives were tested. The epoxy and polyurethane adhesives showed, respectively, ductile and fragile behavior. The adherence of the bonded joints was evaluated using pull-off tests. Pultruded samples treated with UA and bonded with the polyurethane adhesive presented higher strength (13 MPa). Geopolymer samples bonded with the epoxy adhesive and treated with UA reached a failure tensile of 8 MPa. Considering the different testing conditions evaluated in this work, the best combination of an adhesive type and surface treatment produced an increase in the pull-off strength of 220 and 240% in pultruded composite bonded joints and geopolymer bonded joints, respectively.

Keywords:

• Pull off test
• pultruded composites
• geopolymer
• epoxy adhesive
• polyurethane adhesive

Acknowledgments

The authors would like to acknowledge the support of the Brazilian research agencies CNPQ, CAPES and FAPERJ and the Brazilian companies Pultrusão do Brasil and Masterpol by the technical support and materials.

Disclosure statement

None.