Bonding in fabric–cement systems: Effects of fabrication methods Alva Peled a, ⁎ , Sachiko Sueki b , Barzin Mobasher b a Structural Engineering Department, Ben Gurion University, Beer Sheva, 84105, Israel b Department of Civil and Env. Engineering, Arizona State University, Tempe, AZ, 85287, United States Received 24 January 2006; accepted 16 May 2006 Abstract This paper compares the effects on the bond between fabric and cement matrix of three different processing methods: casting, pultrusion and vacuum condition. The fabrics included bonded glass mesh, woven polyvinylalcohol, and warp knitted weft insertion polypropylene. Pullout tests were performed to examine the bond between fabric and cement matrix. A microstructural analysis was conducted and correlated with pullout data. Improved bonding was obtained for fabric–cement composites produced with the pultrusion process, particularly for fabrics composed of multifilament yarns that have open junction points and no sizing to seal individual yarns. This improved bonding results from the impregnation of the fabric in the cement chamber during the pultrusion process, which filled the spaces between the filaments of the multifilament yarns. © 2006 Elsevier Ltd. All rights reserved. Keywords: Processing; Pullout strength; Cement; Composite; Fabric 1. Introduction Bonding at the fiber–matrix interface plays an important role in controlling the mechanical performance of cementitious composites. Several researchers have studied the bond char- acteristics of fiber–cement systems using analytical and experimental techniques [1–6]. The bonding of polymeric fibers with cement-based systems is relatively poor, which has limited the use of these ductile fiber systems. The use of polymeric fibers in the form of fabric can invoke geometrical interlock and improve the bond by mechanical means. Several promising results with cement-based products reinforced with fabrics have been reported [6–13]. In addition to ease of manufacturing, fabrics provide benefits such as excellent anchorage and bond development showing a signif- icant improvement over fibers [6,9]. Peled et al. [8] found that the flexural strength of cement-based composite products incorporating low modulus polyethylene fabrics is almost twice as high as that of composites reinforced with straight continuous polyethylene yarns. This was due to enhanced bonding between the fabric and the cement matrix, which depends mainly on the geometry of individual yarns within the fabric structure [6,8,9]. This paper examines that special fabric geometry and the proper infiltration of matrix between fabric components, which provides mechanical anchoring of the reinforcing yarns. The pultrusion process is an efficient production method for fabric–cement composites that employs a simple set-up of low cost equipment [12–14]. During pultrusion, continuous rein- forcements are impregnated in fresh matrix and then pulled through a set of rotating cylinders that apply pressure, remove excess matrix, and form fabric composite laminates. Recent publications discuss the development of this production method and some preliminary results [12,13]. Several studies have examined the effects of processing on interface characteristics [12–19]. Igarashi et al. [18] found that for a given processing method, materials, and fibers, increasing the processing time of the fresh mixture influences the fiber– matrix bond strength due to changes in the interfacial microstructure. Delvasto et al. [17], Peled and Mobasher [12] and Mobasher et al. [14] found that applying pressure to composites after casting increased the mechanical performance of cement composites. Peled and Shah [19] compared the properties of cast and extruded composites composed of similar matrices and fibers; they found significant effects due to the processing method. But, more information on the effects of processing on interface characteristics is needed to truly Cement and Concrete Research xx (2006) xxx – xxx + MODEL CEMCON-03441; No of Pages 11 ⁎ Corresponding author. E-mail address: alvpeled@bgu.ac.il (A. Peled). 0008-8846/$ - see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.cemconres.2006.05.009 ARTICLE IN PRESS