Title: Strain-Hardening Ambient-Cured Eco-Friendly Ductile Geopolymer Composites
Author(s): Mohammed Farooq, Aamer Bhutta, and Nemkumar Banthia
Publication: Materials Journal
Appears on pages(s): 181-189
Keywords: eco-friendly ductile geopolymer composite (EDGC); fly ash; geopolymer; hybrid binder; polyvinyl alcohol (PVA) fiber; slag; strain hardening
Ambient-cured eco-friendly ductile geopolymer composites (EDGCs) with 2% uncoated polyvinyl alcohol (PVA) microfibers were developed using fly ash and slag hybrid binder in different proportions, natural sand, and sodium silicate and sodium hydroxide as alkaline activators. Two curing conditions, air-curing and water-curing at ambient temperature, were examined. Results showed that the 100% slag-EDGCs exhibited stiff workability, short setting time of 25 minutes, and provided highest compressive strength (82 to 85 MPa), while 100% fly ash-EDGCs had a long setting time of 4 hours and compressive strength was much lower (12 to 24 MPa). In terms of tensile stress-strain behavior, all EDGCs demonstrated a strain hardening response. The 100% fly ash-EDGCs had a low tensile strength around 3 MPa with high tensile strain capacity (>3%). On the other hand, 100% slag-EDGCs had much higher tensile strength (>5 MPa) with reduced ductility due to fiber rupture resulting from an over-optimal bond between the PVA fibers and EDGC matrix.