Abstract
Mode II shear fracture process can be observed in plain-concrete structures exposed to intensive loadings such as shock, blasting or projectile-impact. It is the reason why the quasi-static and dynamic shear fracturing properties of concrete need to be investigated. In previous works performed by Forquin and coauthors a passive confining cell was applied to PTS (Punch-Through-Shear) specimens in a similar way than in quasi-oedometric compression tests where metallic ring are used as passive confinement. However the change of confining level during the sample loading constitutes a main drawback of this technique. In the present work a novel testing method is proposed based on a pre-stressing of the sample. To do so, the concrete specimen is inserted into pre-stressed metallic cell. During the unloading stage confining stresses are transferred to the ligament of the sample. In a second stage, a differential displacement applied to the central part of the sample toward the side parts produces a shearing of the ligament. The experiments performed in static and dynamic conditions (SHPB testing) allow the shear response of concrete to be determined over a wide range of strain-rates. In the present communication, the testing technique and obtained results are compared to the obtained data with the previous experimental method.
Highlights
When exposed to extreme loadings such as blasting or projectile-impact concrete structures as nuclear power plants, dams, bridges or bunkers suffer from intense tensile and shear damage modes as, for instance, cratering, multiple cracking, spall fracturing of shear failure [1,2]
Shear fracturing in mode II was identified in the confined zones of ultra-high strength concrete targets subjected to edge-on impact tests and normal impact tests [3,4]
A passive confining cell was used instead of hydraulic pressure to apply a confinement to the Punch Through Shear (PTS) specimen (Fig. 1) in a similar way than in quasioedometric compression tests [7,8]
Summary
When exposed to extreme loadings such as blasting or projectile-impact concrete structures as nuclear power plants, dams, bridges or bunkers suffer from intense tensile and shear damage modes as, for instance, cratering, multiple cracking, spall fracturing of shear failure [1,2]. A passive confining cell was used instead of hydraulic pressure to apply a confinement to the PTS specimen (Fig. 1) in a similar way than in quasioedometric compression tests [7,8] This testing technique, named oedo-PTS, allowed the quasi-static and dynamic shear behaviour of dry and wet common concrete to be investigated [9,10]. It is the reason why a new testing technique was developed in 3SR laboratory based on a prestressed metallic ring with the aim to better control the confining level in the sheared sample. The results are compared to those obtained with previous testing technique (passive confinement)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
