Title: Basalt Fiber-Reinforced Polymer and Hybrid Grid-Confined Concrete with Organic/Inorganic Resins

Author(s): Yail J. Kim and Manish Solanki

Publication: Structural Journal

Volume: 118

Issue: 5

Appears on pages(s): 37-48

Keywords: basalt; fiber-reinforced polymer (FRP); rehabilitation; resin; retrofit; strengthening

DOI: 10.14359/51728068

Date: 9/1/2021

Abstract:
This paper presents the behavior of concrete confined by basalt fiber-reinforced polymer (BFRP) and BFRP-polyester hybrid grids exposed to elevated temperatures ranging from 25 to 150°C (77 to 302°F). The functionality of organic (epoxy) and inorganic (geopolymer) resins is studied comparatively. A total of 75 cylinders are monotonically loaded in compression to examine the axial capacity, post-peak deformability, and failure modes. Ancillary tests indicate that the thermal degradation of the geopolymer resin is not as significant as that of the epoxy resin and that the strength of BFRP and polyester grids dwindles with temperature. The geopolymer resin outperforms its epoxy counterpart in terms of confining efficacy under thermal distress, leading to an insignificant reduction in the cylinder capacity. The residual load-carrying mechanism of the confined concrete is enhanced by the hybrid grids along with an increase in energy dissipation. The thermal loading changes a confining pressure distribution so that the failure of the confined concrete with the epoxy resin entails irregular fiber rupture at temperatures exceeding 100°C (212°F). Owing to the high rupture strain of the polyester grids (over 7%), disintegration of the hybrid-confined concrete is impeded. Analytical modeling characterizes the capacity degradation rate and reliability of the test specimens.