Stress-strain relation of confined concrete under dynamic loading

A dynamic compression test was carried out on 126 cylinder specimens, which has 75 mm in diameter and 150 mm in height with or without confining spirals, in order to study strain rate effects on the stress-strain relation of confined concrete, Test variables were strain rate (static to 0.1/s), original compressive concrete strength (30 MPa to 54MPa), amount of confining spiral (unconfined to 2.0% in volume ratio), and its yield strength (300 MPa and 850 MPa). It was found that the unconfined concrete had a strong strain rate sensitivity with respect to the peak stress and peak strain but the sensitivity decreased as the confining transverse stress increased. The enhanced peak stress increased linearly with the confining transverse stress when specimens had a same strain rate.