ISSN 0020-1685 Inogm'c Morcrh*, 2008, Vol. 44 No. 5 p. 549-554.0 Plehdes Publishing, Ifd., 2008. Ori&d uss sib Tcu 0 J.L Reyu-Amia A. M.&w$~Tc~ J.C. Rubio-Avalos, E. Gonaz-Som I.E PCnL.Robks, M. Arroyo-Conlreras, C. Signon,, E. C~i110- CpCt(plCda,.Y1V bmbkv, 2008. published in Neog~lchrskie Mafew 2008, bl. 44. No. 5. pp. 632638. Comparative Study on Tensile Behavior of Inorganic Fibers Embedded in Unsaturated Polyester Bisphenol "A9'-Styrene Copolymer J. L. Reyes-Araiza" A. Manzano-Ramirezb, J. C. Rubio-AvaloF, E. Gonzsllez-Sosad, J. F. P - M. Arroyo-Contrerd, C. Signoreta, E. Castillo-Castaiiedad, and Y. V. Vorobievb a DEPFI, Facultad de Ingenierfa, Universidad Autdnoma de Querktaro, Querbtam, Querbtam, C. I? 76010, Mbxico Centm de Investigaciones y de Estudios Avanzados del I.I?N.Querktaro, Querktaro, C. l? 76230, Mbxico Civil Engineering Faculty, Universidad Michoacam de San Nicolh de Hidalgo, Morelia, Michoach, C.I? 58000, Mbxico Civil Engineering Faculty, UniversidadAutdnoma de Querktaro, Querbtaro, C. R 76010, Mbxico Research fellow at Tecnoldgicode Estudios Superiores de Monterrey, Campus Querkram, Querbtaro, MRrico, C.l? 76130 e-mail: reyesaraiza@yahoo.com.mr, jcrubioa@yahoo.com, egs@uaq.m; csignore@itesm.mx Abstract - Due to their worldwide availability,glass fibers and aramid fibers have been the more common con- tinuous fibers used to obtain fiber reinforced polymer (FRP) rods. These pultruded rods are used as structural materials and for reinforcements of concrete elements. The main challenge that these fibers face in concrete is their durability in high alk;?ine environments, therefore the fibers appropriate for this application must be alkali - resistant (AR). In the present work, a cheap Basalt fiber embedded in unsaturated polyester bisphenol " A"- styrene copolymer has been compared to 'Ti" and AR glass fibers under unidirectional tensile strength. A pultrusion process was used to obtain FRP rods. After unidirectional tensile tests of the FRP rods along with durability tests (fibers immersed in a highly alkaline solution at constant temperature simulating the concrete pore solution), the FRP rods with basalt fibers showed to be a cheap and good alternative to be used in concrete. DOI: 10.1 134/S0020168508050221 INTRODUCTION Current fiber reinforced polymer (FRP) composites for structural applications use mainly three types of continuous fibers: carbon, ararnid, and glass, usually identified as CF'RP, AFRP, and GFRP composites, respec - tively. Among them, Eglass fibers are the most commonly used since they are the cheapest (around US 3.36 per kil~ gram). Their tensile modulus is around 72 GPa, while ten- sile strength is around 3450 MPa with a strain of 4.8%. However in composite applications ultimate strains are around 2.596, which is more common, with the corre- sponding screnfl reduction [I]. The use of other fibers such as Vinylon (polyvinyl alcohol, PVA) and Polyes- ter, but in limited applications is reported [2]. The fiber content for pultruded composites is usually from 45 to 68% by volume (i.e., 60 to 80% by weight) [2].Among the functions and requirements of the matrix are found: to keep the fibers in place in the structure, to help dis- tributing or transferring loads and to protect the fila- ments [3]. In concrete structures (alkaline media), the resin matrix protects glass fibers from direct contact in the glass fiber reinforced polymer (GFRP) composite [4] and slows the diffusion process of high alkaline solution. Moreover, the type of matrix used and its toughness plays an important role in the charatteristics such as matrix cracking and debonding of the fiberlmatrix interface [5-121. Modified polyester resins could be used as composite matrix. Good alkaline resis- tance can be obtained by incorporating special compo- nents into the resin (e.g. bisphenol derivatives, in this case bisphenol LLfl, others additives can be used, for instance neopentylglycol, isophthalic acid, but the best resistance against alkali is shown by bisphenol resins [13]. Epoxies can be more resistant but they are more expensive [23. On the other hand, FRP bars show a lack of ductility, therefore it could be thought that the struc- tural failure in reinforced concrete beams is induced for the FRP reinforcing bar rupture, and moreover could be catastrophic. As a result of this, the over-reinforced design concept that ensures that compressive failure of concrete takes place prior to the tensile failure of FRP has been well accepted [14-171. Efforts to develop new types of ductile hybrid FRP composites with deliber- ately designed fiber architecture have been made [S]. The present article shows the comparative tensile study of pultruded rods, using three different synthetic fibers: