A study of the effect of displacement rate and moisture content on the mechanical properties of concrete: Use of acoustic emission

Ranjith, P.G.; Jasinge, Dileeka; Song, Jingchao; Choi, Sing-Ki Xavier

doi:10.1016/j.mechmat.2007.11.002

Cited by 123 publications

(55 citation statements)

References 15 publications

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“…Several methods, including stress-strain relationships, scanning electron microscopy, photo-elasticity and AE monitoring, have been used to identify the different phases of the rock fracturing process (Ranjith et al 2008). Of these, the AE monitoring technique has been of particular interest to researchers, as it is a simple method with proven reliability (Perera et al 2011;Rathnaweera et al 2013;Perera and Ranjith 2013).…”

Section: Ae Monitoring For Characterizing Rock Fracturingmentioning

confidence: 99%

Do joint geometrical properties influence the fracturing behaviour of jointed rock? An investigation through joint orientation

Wasantha

Ranjith

Zhang

et al. 2015

Geomech. Geophys. Geo-energ. Geo-resour.

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Failure of brittle rock is often progressive and understanding the fracture development process within rock masses is important to identify the precursors of failures. Joints in rock masses influence the fracture progression behavior and we studied the influence of joint orientation on fracture progression in jointed rock. Undrained triaxial tests were conducted on 54 mm diameter and 108 mm high intact and singly-jointed sandstone specimens. The joints in jointed specimens were made rough (joint roughness coefficient = 10-12) and embedded in six different orientations-0°, 30°, 45°, 60°, 75°and 90°-and three different combinations of confining and initial pore-water pressures were considered (confining pressure/pore-water pressure = 4/1, 10/4 and 25/10 MPa). An acoustic emission (AE) monitoring system was employed during all tests to monitor the fracture development within the test specimens. The post-failure patterns of specimens displayed three different failure mechanisms-shearing through intact material, sliding along the joint and a mixture of both shearing and sliding-depending on the joint orientation and confining pressure. The fracture progression behavior of the specimens showed a strong correlation with these failure mechanisms. Intact specimens and specimens with joints oriented at 0°, 30°, 90°failed by shearing. Nevertheless, the AE patterns of intact specimens and specimens with 90°-oriented joints contrasted with those of specimens with joints oriented at 0°a nd 30°. Specimens with joints oriented at 60°failed by sliding with a constant rate of acoustic event generation starting from the beginning of deviatoric loading. A mixed failure mechanism was observed for specimens with joints oriented at 45°and 75°. While the characteristics of both sliding and shearing failure were observed from the AE patterns of both 45°and 75°orientations, the shearing failure component of the 75°case was found to be a result of experimental limitations rather than real behavior. Finally, we propose a family of typical AE curves to assist with the characterization of the fracture progression behavior of jointed rock by taking confining pressures and failure mechanisms into consideration.

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Section: Ae Monitoring For Characterizing Rock Fracturingmentioning

confidence: 99%

Do joint geometrical properties influence the fracturing behaviour of jointed rock? An investigation through joint orientation

Wasantha

Ranjith

Zhang

et al. 2015

Geomech. Geophys. Geo-energ. Geo-resour.

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“…Furthermore, former studies on the TM properties of rocks have not considered the characterization of crack growth during the TM study of the rock. The mechanical behaviour of rock has been analysed by varoius researchers using an acoustic measurement method (Ranjith et al 2008;Wasantha et al 2013). They differentiated the stable crack growth zone and rock failure zone of different rock specimen using the acoustic emission counts.…”

Section: Thermo-mechanical Studymentioning

confidence: 99%

Thermo-mechanical properties of Bundelkhand granite near Jhansi, India

Singh

Ranjith

Chandrasekharam

et al. 2015

Geomech. Geophys. Geo-energ. Geo-resour.

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Creation of optimal fracture networks through enhanced geothermal system within the reservoir for the extraction of the geothermal energy will require proper understanding of the thermo-mechanical behavior of the reservoir rocks i.e. granites. Current research work has focused the thermo-mechanical properties of granite under various temperature and strain rate conditions. Bundelkhand granite of India has been investigated for the proposed research work. Four different strain rates viz. 0.05, 0.5, 5.0 and 50.0 mm/ min at three different temperatures viz. room temperature (25°C), 200 and 400°C were considered for experimental analysis. It was observed that at room temperature, with increasing strain rate the uniaxial compressive strength of the rock increases and the same trend is also observed at higher temperature conditions. However, at low strain rate (0.05 mm/min) the compressive strength decreases with increase in temperature and the trend is irregular at higher strain rates. It was also observed that Young's modulus of Bundelkhand granite increases with increase in strain rate however it reduces with increase in temperature. Thermal conductivity value of Bundelkhand granite ranges from 3.1 to 3.6 W/m K.

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“…The combined effect of moisture and strain rate was specifically investigated also for concrete [29][30] and a marked reduction in compressive and flexural strength for increasing water contents was found, especially at lower displacement rates (static conditions) [29][30], while saturation seems to cause much higher strength at high strain rates and for impact loads [31]. The strain rate sensitivity of concrete strength to water was explained through different concepts, such as the 'viscous cohesive stress' of free water in the pores (e.g., [30]) or the wave propagation concept [31].…”

Section: Introductionmentioning

confidence: 99%