Evaluation of Bond Properties of a Fabric-Reinforced Cementitious Matrix for Strengthening of Concrete Structures  
[PERSON]  
1 Land and Housing Institute, Korea Land and Housing Corporation, Daejeon 34047, Korea; [EMAIL_ADDRESS]  
[PERSON]  
2 Department of Architectural Engineering, Kongju National University, Cheonan 31080, Korea;  
[EMAIL_ADDRESS] (H.-G.K.); [EMAIL_ADDRESS] (D.-H.K.)  
[PERSON]  
3 Korea Construction Standards Center, Korea Institute of Civil Engineering and Building Technology,  
Goyang 10223, Korea; [EMAIL_ADDRESS]  
[PERSON]  
2 Department of Architectural Engineering, Kongju National University, Cheonan 31080, Korea;  
[EMAIL_ADDRESS] (D.-H.K.); [EMAIL_ADDRESS] (D.-H.K.)  
[PERSON]  
4 CareCon Co., Ltd., Seoul 05586, Korea; [EMAIL_ADDRESS]  
Correspondence: [EMAIL_ADDRESS]; Tel.: +82-41-521-9335  
a temperature equal to or higher than a specific value (glass transition temperature). The method also has a disadvantage in that it cannot be applied to wet surfaces or at low temperatures. Furthermore, the low economic feasibility and toxicity of epoxy adhesive limit its serviceability [9].  
To overcome these disadvantages of FRP reinforcement methods, research is now being conducted on reinforcement using fabric-reinforced cementitious matrix (FRCM). FRCM is a method where a cementitious matrix and textile are combined to reinforce the concrete surface [10]. In general, the cementitious matrix is a binder composed of Portland cement, silica fume, and fly ash. Carbon and glass fibers are widely used as textiles.  
The FRCM reinforcement method provides improved economic feasibility and utility when compared to FRP reinforcement because the cementitious matrix is used instead of an epoxy bond. Additionally, the method may allow for high tensile strength and pseudo-ductile behavior depending on the type of used textile, and high durability is ensured because corrosion does not occur due to the intrinsic characteristics of the textiles [11]. These advantages have made FRCM reinforcement widely available for the repair and reinforcement of buildings and structures. However, when a matrix that composes the FRCM is highly alkaline, the durability of the used textiles may deteriorate. Thus, more research regarding this issue is needed [12; 13].  
Previous studies have conducted research on the bond between the matrix and textiles in attempts to examine the bond strength with respect to the properties of the matrix [14; 15]. Additionally, many studies have performed bond tests, where the matrix and textiles were selected as test parameters and the strain behavior of textiles was examined with respect to the bond stress [16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26]. However, in previous studies, investigations into the alkalinity of the matrix, which may deteriorate the durability of textiles used in FRCM, have not been conducted. Recently, [PERSON] et al. [27], [PERSON] et al. [28], and [PERSON] et al. [29] studied the durability of textiles but did not evaluate the durability of textiles applied to the FRCM.  
In order to ensure the durability of the FRCM and effective reinforcement of RC elements, it is necessary to develop a matrix that is alkali-resistant [30; 31]. Therefore, in the present study, a matrix with alkali resistance was developed in an attempt to achieve the required durability for the textiles used in the FRCM. Furthermore, to make the developed matrix available for the repair and reinforcement of RC elements, pull-out and pull-off tests were conducted as preliminary research. Based on these results, the bond characteristics between the developed matrix and the textile were evaluated.