Effect of test setup on the fiber-to-mortar pull-out response in TRM composites: Experimental and analytical modeling

Abstract

Textile-reinforced mortars (TRM) have recently received significant attention for the externally bonded reinforcement (EBR) of masonry and historical structures. The fiber-tomortar bond, the TRM-to-masonry bond, and the mechanical properties of the TRM constituents have a fundamental role in the performance of this strengthening technique and therefore require special attention. Despite this importance, only few investigations are devoted to characterization of the single fiber-to-mortar bond response in these systems. This paper, as an step towards addressing the fiber-to-mortar bond, presents a combined experimental and analytical investigation on the effect of test setup on the pull-out response and bond-slip laws in TRM composites. Three different pull-out test setups, consisting of one pull-pull and two pull-push configurations, are developed and investigated for characterization of the single fiber-to-mortar bond behavior. The experimental and analytical results are critically discussed and presented and bond-slip laws are extracted for each test setup.

Mechanics and durability of lime-based textile reinforced mortars

“…the textile-tomortar bond behaviour, and the parameters affecting that, remain poorly addressed and understood, see e.g. [1,20,21].…”

“…[22][23][24][25][26][27], the existing literature on the bond behaviour of TRM composites that are of interest for strengthening of masonry structures is very limited, (see e.g. [1,20,21] for a steel and a glass-based TRM).…”

“…The variability of the experimental results are also smaller in a single-sided testing scheme [8]. Comparison between the experimental results obtained from different tests setups should be done with special care, as due to the differences in the boundary conditions and stress distribution between these two test methods, the peak load and toughness of the samples tested under a double-sided testing scheme are higher than the samples tested under a single-sided testing scheme [20,21,26].…”

“…This requires accurate measurement of the fibre slip (at both loaded and free ends of the sample) and the strain/stress distribution of the fibre along its embedded length. However, due to the complexity of measurement of the fibre slip at the free end or lack of equipment for measurement of strain distribution along the embedded length, only the fibre slip at the loaded end has been measured and reported in the existing studies [20,21,34].…”

“…As mentioned before, the existing literature on pull-out response of TRM composites used for strengthening of masonry structures is still very limited. Recent studies have shown the important role of fabric configuration (unidirectional/bidirectional), loading rate (in the quasi static range), embedded length and mortar age (at the time of testing) on the pull-out response and bond behaviour of a limited number of existing commercial TRM types [20,21,34]. While there is a need for future studies on other TRM types, the unaddressed role of textile chemical/physical properties, configuration and texture (type of connection at the junctions, grid spacing, etc.…”