Freeze-Thaw Durability of Lime Based FRCM Systems for Strengthening Historical Masonry

Abstract

In recent years, FRCM systems have become a preferred strengthening system in reinforced concrete structures together with masonry structures. The most important factor in the choice of FRCM as a strengthening system is its compatibility with concrete or masonry substrates. In addition, high fire resistance is an important factor in their preference. The components of FRCM composites are known to have high durability separately. However, the durability of composites, composed of a combination of fabric and matrices is still a matter of no detailed reported knowledge. In this experimental study, the durability properties of FRCM composites with lime matrix reinforced with glass and glass-polypropylene hybrid fabrics were investigated. Composite samples were subjected to tensile and bending tests before and after freeze thaw cycles. Load-deformation relations were obtained. As a result of the experimental study, the following results can be drawn: Following freeze thaw cycles, reduction in the bending and tensile performances of the biaxial glass fabric reinforced composite samples as well as matrix samples were obtained. A significant decrease of deformation capability was determined for biaxial glass fabric reinforced matrices and plain matrix.

Durability of Fabric-Reinforced Cementitious Matrix (FRCM) Composites: A Review

“…These guidelines recommend test methods to evaluate the durability of the FRCM including freeze-thaw cycles, ageing in high-moisture condition (hygrothermal environment), concentrated solutions (chloride and sulfate solutions and alkaline environments), and even exposition to fuel (not covered in this paper). Since these guidelines are quite recent, different test methods were adopted in the past by some researchers [14,22,26,36,38] and the results obtained could not be easily compared due to the differences in ageing temperature, number of cycles, and solution type. In this section, the results found in the literature are discusses and critically compared in an attempt to gain general indications on the long-term performance of FRCM and TRM composites.…”

“…In general, if the material saturation is lower than a certain threshold, the material is considered resistant to frost, i.e., dry materials should not be affected by frost [22]. ASTM C666 [39] recommended a low temperature range of (4 to −18 • C) with a short cycle length of 2-5 h. EN 12467 [38] adopted freezing at −20 • C for 1-2 h and thawing at 20 • C for 1-2 h. Pekmezci et al [14] performed 6 h of freezing at −25 • C followed by 2 h of thawing in water at 20 • C. Finally, AC 434 (2018) [23,28] and CSLLPP (2019) [24] utilized a wide temperature range and a long cycle period (4 h at −18 • C and 12 h at approximately 38 • C).…”

“…The inorganic matrix employed in FRCM composites is generally cement-based or lime-based, although other types can be found in the literature (see e.g., [14,[19][20][21]). This section focuses on the durability of cement-based and lime-based mortars.…”

“…However, researches available regarding freeze-thaw of FRCM composites did not generally report the specimen moisture content. Figure 2 presents the effect of the freeze-thaw cycles on the retained cracking (tensile) strength of different FRCM matrices, which was determined by uniaxial tensile test on FRCM [14,28] and TRC [22,26] coupons. The details of freeze-thaw cycles utilized in each study are indicated in the legend of Figure 2.…”

“…In addition, textile yarns can be coated with organic resin to improve their bond with the matrix, FRCM ease of handling and installing, and to protect the fiber filaments. Various types of inorganic matrix can be found in the literature, such as cement-based and lime-based mortars and geopolymers, sometimes modified with fly ash, polymers, silica fume, and short fibers to increase the adhesion to the textile and substrate [7,[14][15][16][17][18]. FRCM composites are generally employed as externally bonded reinforcement (EBR) for masonry [19] and RC members [20].…”