Title: Effect of Bonded Length on Material Characterization of FRCM Composites

Author(s): Houman Hadad, Davide Campanini, and Antonio Nanni

Publication: Symposium Paper

Volume: 345

Issue:

Appears on pages(s): 86-101

Keywords: Bond, Composite Materials, Fabric Reinforced Cementitious Matrix (FRCM), Material Characterization, Strengthening, Tensile testing

DOI: 10.14359/51731573

Date: 2/1/2021

Abstract:
Fabric Reinforced Cementitious Matrix (FRCM) is an established technology for strengthening and rehabilitation of existing concrete and masonry structures. In the United States, material characterization of the FRCM composites is in accordance with ICC-ES acceptance criteria AC434. The acceptance criteria recommend tensile testing the FRCM coupons with clevis-grips to obtain the mechanical properties for design purposes. The current test method, however, neglects some of the critical factors affecting the test outcome such as the effect of bonded length or number of fabric layers. The effect of bonded length on the FRCM properties tested per AC434 Annex-A is discussed in this paper. Carbon-FRCM coupons of 2, 3, 6, 9, and 12 inches (50.8, 76.2, 152.4, 228.6, and 304.8 mm) bonded length were prepared and tested in direct tension. The other test variable was the number of fabric layers. The tests were conducted with one- and two-layer fabrics for different bonded length. The results discussed in terms of ultimate stress, ultimate strain, and modulus show that the material characterization of the FRCM composites depended on the bonded length and number of fabric layers of the tested specimens. Moreover, the effect of number of fabric layers on the material characteristics was more pronounced in specimens with shorter bonded length. The experimental results are used to make suggestions for improving the FRCM characterization test methods as currently stated in AC434.