The post peak response of concrete for dynamic tensile loading
conference paper
The mechanical response of concrete is represented in the load-deformation curve which shows the response up to maximum strength as well as the post-peak response up to complete failure. Dynamic tests exhibit an extensive rate effect on the tensile strength beyond loading rates of about 50 GPa/s (strain rates > 1/s). Whether the apparent strength increase is real material response or that it is affected by inertia effects at macro and micro scale is under discussion. The authors contributed to discussion by their instrumented SHB and spalling tests. By measuring the deformation in the failure zone directly and real time, the contribution of inertia could be demonstrated and estimated quantitatively. The direct measurement of the deformation also holds for the post-peak process. Data on the post-peak response and the analysis of the data will be presented in this paper. In the experimental programme a reference concrete was tested at three moisture levels, i.e dry, normal and saturated. Static, SHB and spalling tests were performed so data on a wide range of loading rates was obtained. The analysis presented in the paper addresses the effects of (i) the pore saturation level, (ii) the amount of micro cracks in the failure zone, (iii) the limited crack velocity, (iv) the micro inertia effect on crack initiation and (v) the structural inertia of failure zone. The latter proved to be only relevant during the pre- and post peak micro cracking process at the high loading rate regime.
Topics
TNO Identifier
522758
Source title
Design and Analysis of Protective Structures (IAPS). Proceedings of the 3rd International Conference on Protective Structures (ICPS3), Newcastle, Australia, 3-6 February 2015
Pages
655-662