Title:
PBO FRCM Composite System Exposed to Elevated Temperatures: Experimental and Theoretical Investigations
Author(s):
Luciano Ombres, Pietro Mazzuca, Alfredo Micieli and Francesco Campolongo
Publication:
Symposium Paper
Volume:
360
Issue:
Appears on pages(s):
648-662
Keywords:
PBO, FRCM, inorganic matrix, composites, temperature, tensile behavior, bond behavior, mechanical characterization tests, theoretical study
DOI:
10.14359/51740654
Date:
3/1/2024
Abstract:
This paper presents experimental and theoretical investigations on the residual tensile and bond response of polypara-phenylene-benzo-bisthiazole (PBO) fabric reinforced cementitious matrix (FRCM) composites after the exposure to elevated temperatures ranging between 20 °C [68 ºF] and 300 °C [572 ºF]. Experimental results obtained from direct tensile (DT) and single-lap direct shear (DS) tests carried out respectively on PBO FRCM specimens and PBO FRCM-concrete elements were reported and discussed. Overall, specimens exposed to temperatures up to 200 °C [392 ºF] did not present significant reductions of both bond and tensile properties. This result can be attributed to the thermal shrinkage underwent by the inorganic matrix, which may enhance the bond between the fibers and the matrix. On the other hand, when the specimens were heated at 300 °C [572 ºF], marked reductions were observed, primarily stemming from the degradation of both mechanical properties of the FRCM constituent materials and the fiber-to-matrix bond. Subsequently, the experimental results were used for the following purposes: (i) to assess whether the Aveston–Cooper–Kelly (ACK) theory is able to describe the tensile behavior of FRCM materials at elevated temperatures; (ii) to define temperature-dependent local bond stress vs. slip law and (iii) to evaluate the ability of degradation models to simulate the variation with temperature of the FRCM tensile and bond properties. The results obtained from the theoretical analyses showed that, for all the tested temperature, the relative differences between predicted and experimental results are very low, confirming the accuracy of the proposed approaches.