Document Type : Original Research Paper
Authors
1 Garmsar Campus, Amirkabir University of Technology, Tehran, Iran
2 Civil and Environmental Engineering Faculty, Amirkabir University of Technology, Tehran, Iran
3 Mining and Metallurgy Faculty, Amirkabir University of Technology, Tehran, Iran
4 Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
Abstract
The present study delves into investigating the impact of sample size and geometry on the mechanical behavior of rock and concrete. More specifically, it examines factors including Uniaxial Compressive Strength (UCS), Elastic Modulus (E), and Pressure Wave Velocity (Vp). Results indicated a notable correlation between the dimensions and morphology of the specimens with these properties. All tests were conducted at a uniform loading rate of 0.002 mm/s. According to the outcomes, the effect of sample size and shape on UCS for concrete is more predictable than for rock. The increase in the sample size led to an initial increase followed by a decline in the UCS values of the rocks. Furthermore, the concrete typically showed a drop in the UCS values as sample size increased. The UCS and E values rose at first before falling, suggesting the existence of a sample size with maximum UCS. The Vp values of the prismatic rock and concrete samples continually grew. After attaining their optimum strength, the prismatic samples showed greater degrees of flexibility and ductility compared to cylindrical ones because of post peak behavior. This suggests that prismatic samples, with their less slender geometry and reduced tendency for brittle behavior, are deemed more suitable for UCS testing. These results can improve the accuracy of assessing the mechanical properties of tunneling materials, particularly those used in subsurface construction in urban roads and highways.
Keywords
- Shape and size effect
- Uniaxial compressive strength
- Elastic modulus
- Pressure wave velocity
- Brittle and Ductile materials
Main Subjects
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