Please cite this article in press as: F.d.A. Silva, et al., Mater. Sci. Eng. A (2010), doi:10.1016/j.msea.2010.11.014 ARTICLE IN PRESS G Model MSA-26766; No. of Pages 8 Materials Science and Engineering A xxx (2010) xxx–xxx Contents lists available at ScienceDirect Materials Science and Engineering A journal homepage: www.elsevier.com/locate/msea Strain rate effect on the tensile behaviour of textile-reinforced concrete under static and dynamic loading Flávio de Andrade Silva a , Marko Butler a , Viktor Mechtcherine a,∗ , Deju Zhu b , Barzin Mobasher b a Institute of Construction Materials, TU Dresden, Georg-Schumann-Str. 7, D-01062 Dresden, Germany b Department of Civil and Environmental Engineering, Arizona State University, Tempe, AZ 85287-8706, United States article info Article history: Received 6 September 2010 Received in revised form 31 October 2010 Accepted 3 November 2010 Available online xxx Keywords: TRC Dynamic loading Strain rate Microstructure Fiber fracture morphology abstract This paper presents the results of an experimental investigation into the strength, deformation, and fracture behaviour of textile-reinforced concrete (TRC) subjected both to low and high-rate tensile loading ranging from 0.0001 to 50 s -1 . High strain rates were achieved using a high-rate servo-hydraulic testing machine. The effect of the addition of short fibres on the static and dynamic response of TRC has been investigated, and the microstructure of both composite and fibre was observed after the tests using an ESEM. An increase in tensile strength, strain capacity, and work-to-fracture was observed for strain rates up to 0.1 s -1 with increasing strain rate. The addition of short glass fibres increased the tensile strength and first crack strength of the TRC. For high-speed tests (rates above 5 s -1 ) an increase in the tensile strength, first crack strength and work-to-fracture was also observed, but at the same time there was a decrease in the strain capacity. The tests at high loading rates showed a pronounced effect of the specimen length on the measured mechanical properties: with increasing gauge length the tensile strength and strain capacity decreased, while the work-to-fracture increased. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Textile-reinforced concrete is a relatively new class in the array of cement composite systems which exhibit strain-hardening behaviour with enhanced strength and ductility [1]. This material is strong enough to be used for production of load-bearing struc- tural members in applications such as structural panels, impact- and blast-resistance structures, repair and retrofit, earthquake remediation, strengthening of unreinforced masonry walls, and beam-column connections. In applications of extreme loading con- ditions, the material response to impulse loading assumes great importance. Mechanical properties of cement-based materials are well known to be dependent on the strain rate [2–7]. Most of the experimental studies under high strain rates (above 1 s -1 ) have been performed using split Hopkinson bar (SHB) tests in cylindri- cal specimens or a modified SHB apparatus with state-of-the-art instrumentation. Grote et al. [2] reported that the compres- sive strength of mortar increases with increase in the strain rate with significant rate-sensitivity in the strain-rate range of 10 -3 –1700 s -1 . This rate dependence is weaker for strain rates below 400 s -1 . At a strain rate of 1500 s -1 , the compressive strength ∗ Corresponding author. Tel.: +49 0 351 463 36311; fax: +49 0 351 463 37268. E-mail address: viktor.mechtcherine@tu-dresden.de (V. Mechtcherine). is 160 MPa or approximately 3.5 times the quasi-static strength. Tensile tests on cylindrical specimens made of wet and dry con- crete have been performed at strain rates ranging from 10–120 s -1 by means of an instrumented Hopkinson bar [3]. These experiments demonstrated a significant increase in tensile strength measured in the range of strain rates above 10 s -1 . This phenomenon was attributed to the micro-cracking inertia, micro-crack shielding, and cleavage of aggregates. Rossi [4] reported as well that for strain rates equal to or greater than 10 s -1 inertial forces are mainly responsible for increasing strength. For strain rates less than or equal to 1 s -1 , an increase in material strength is related to viscous nature of free water in the nanopores of concrete hydrates which is independent of the water/cement ratio. Dynamic tensile data on fibre-reinforced concrete is very lim- ited. However, understanding it correctly is important to derive constitutive equations for analytical models and finite element sim- ulation. Zhu et al. [8] reported high-speed tensile test results on TRC reinforced by AR-glass, carbon, and PE fabrics. For AR-glass TRC the tensile strength raised from 4.11 MPa to 5.56 MPa when the strain rate increased from static (2.2 × 10 -5 s -1 ) to dynamic (18 s -1 ). No significant changes were noticed in strain capacity. Mechtcher- ine et al. [9] studied the dynamic behaviour of strain-hardening, cement-based composites (SHCC) reinforced with PVA fibres under tensile load. It was shown that for tensile tests performed at strain rates up to 10 -2 s -1 with increasing strain rate SHCC exhibited an increase in tensile strength and a decrease in strain capacity. 0921-5093/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.msea.2010.11.014