Tensile Behavior of Fabric Cement-Based Composites:Pultruded and CastA. Peled1and B. Mobasher2Abstract: There is a growing interest in the use of fabrics as reinforcements for cement composites due to their superior performance incomparison to other cementitious composites. This paper compares the effects of two processing methods, casting and pultrusion, on thetensile properties of fabric-cement composites. Four fabric types were used, including bonded glass mesh, woven polyvinylalcohol, wovenpolyethylene, and warp knitted weft insertion polypropylene. The evolution of crack spacing and crack width as a function of appliedstrain as well as stiffness degradation were correlated with tensile responses of various composites. Pullout tests and microstructuralanalysis were conducted to better understand the tensile behavior. The advantages of using pultrusion are clear. Pultruded fabric-cementcomposites exhibited improved mechanical performance, especially those that incorporated knitted fabrics made from multifilament yarnswith an open junction point. This improved performance is due to the improved bonding by the impregnation of cement paste duringpultrusion, which helped fill the spaces between the filaments of the bundled yarns.DOI: 10.1061/共ASCE兲0899-1561共2007兲19:4共340兲CE Database subject headings: Cements; Composite materials; Fibers; Tensile loads; Fabrics; Bonding; Pultrusion.IntroductionNew cement-based composite systems with enhanced perfor-mance can be obtained by impregnating cement paste or mortarsinto a fabric. New types of reinforcements, potential productiontechnologies, and the mechanical properties of the compositeshave been studied recently 共Peled et al. 1999, 1998; Peled andBentur 2000; Kruger et al. 2003; Meyer and Vinkler 2003;Häußler-Combe et al. 2004; Mobasher and Pivacek 1998;Mobasher et al. 1997兲. In addition to the ease of manufacturing,fabrics provide benefits such as excellent anchorage and bonddevelopment 共Peled et al. 1999兲, and improve composite behavior共Peled et al. 1998; Peled and Bentur 2000兲. The mechanical prop-erties of composites incorporating continuous yarns produced byfilament winding processes have been reported by Mobasher et al.and others 共Mobasher and Pivacek 1998; Mobasher et al. 1997;Kazuhisa et al. 1998; Nishigaki et al. 1991兲. Results indicate thatcement composites containing 5% 关alkali resistance AR兲兴 unidi-rectional glass fibers achieved a tensile strength of 50 MPa共Mobasher and Pivacek 1998; Mobasher et al. 1997兲; conven-tional glass fiber-reinforced cement 共GFRC兲 composites have anaverage tensile strength of only 6–10 MPa. Similar products re-inforced with polyacrylnitril 共PAN兲-based carbon continuous fila-ments achieve superior flexural strength of about 600 MPa with16% content by volume 共Kazuhisa et al. 1998兲 and 800 MPa with23% content by volume 共Nishigaki et al. 1991兲. The concepts offilament winding were recently extended to a pultrusion processthat could be used for mechanical impregnation of fabrics in anindustrial setting 共Mobasher et al. 2005; Peled and Mobasher2005; Peled et al. 2004兲.Results of various studies suggest that the manufacturing pro-cess significantly affects the properties of the composite 共Igarashiet al. 1996; Delvasto et al. 1986; Peled and Shah 2003兲. Using thesame processing method, materials, and fiber, Igarashi et al.共1996兲 found that increasing the processing time of the fresh mix-ture influences the fiber-matrix bond strength due to changes inthe interfacial microstructure. Delvasto et al. 共1986兲 found thatthe flexural response performance of the composite depended onthe applied pressure after casting. Pressed composites showed anincrease in flexural strength but a reduction in the postcrackingresponse. Peled and Shah 共2003兲 found significant differences inthe properties of cast and extruded composites with similar matrixand fiber.A more fundamental understanding of the effects of pultrusionon fabric cement-based composites will aid both design and fab-rication. This paper compares the tensile properties of cementcomposites reinforced with various fabric types and made by twodifferent processing methods, casting and pultrusion. The studycorrelates composite behavior with bond and microstructuralcharacteristics.Multiple cracking characterizes the tensile behavior of fabric-cement composites. The nature of multiple cracking and the re-sulting stress-strain curve, toughness, and strength are dependenton the properties of the fabric and cement matrix, the interfacebond, and the fabric anchorage. Therefore, microstructural fea-tures such as crack spacing, width, and density as well as thecomposite stiffness in the postcrack range are chosen to correlatethe effect of materials and processing methods to changes in ten-sile strength, strain capacity, and ductility.Factors including fabric type, structure, and processing meth-ods are addressed in the context of tensile stress, crack spacing,1Senior Lecturer, Structural Engineering Dept., Ben Gurion Univ.,Beer Sheva 84105, Israel. E-mail: [email protected], Dept. of Civil and Environmental Engineering, ArizonaState Univ., Tempe, AZ 85287-5306. E-mail: [email protected]. Associate Editor: Houssam A. Toutanji. Discussion open untilSeptember 1, 2007. Separate discussions must be submitted for individualpapers. To extend the closing date by one month, a written request mustbe filed with the ASCE Managing Editor. The manuscript for this paperwas submitted for review and possible publication on June 28, 2005;approved on April 24, 2006. This paper is part of the Journal of Mate-rials in Civil Engineering, Vol. 19, No. 4, April 1, 2007. ©ASCE, ISSN0899-1561/2007/4-340–348/$25.00.340 / JOURNAL OF MATERIALS IN CIVIL ENGINEERING © ASCE / APRIL 2007crack width, and stiffness degradation as a function of appliedstrain. The pultruded and cast composites incorporated bondedglass mesh fabric, woven polyvinylalcohol 共PVA兲 and polyethyl-ene 共PE兲 fabric, and warp knitted weft insertion polypropylene共PP兲 fabric. Pullout tests were conducted to examine the bondbetween the fabric and the cement matrix. Finally, a qualitativeexamination of the microstructure of the composites was con-ducted using optical and scanning electron microscopy andcorrelated with the mechanical properties of the composite andinterface bond.Experimental ProgramFabric TypesThree types of fabrics were