Impact of End Friction and Lateral Inertia Confinement on the Dynamic Compressive Performance of Standard and High-Strength Concrete

Present study focused on to investigate the impact of end friction and lateral inertia on the dynamic properties of concrete obtained by performing the dynamic compression test on developed split Hopkinson pressure bar (SHPB) setup. The standard (SC) and high-strength concrete (HSC) exhibiting characteristic compressive strength of 35 and 60 MPa, respectively used in the present investigation. The concrete specimens with 29.5 and 45 mm diameter describing the aspect ratio about of 1 and 0.67, respectively, has been subjected to strain rates ranging from 78 to 336 s⁻¹. The systematic experimental analysis of the influence of strain rate, end friction, and lateral inertia has been performed on the dynamic compressive properties. The influences of these factors on the dynamic compressive strength (DCS) and dynamic increase factor (DIF) have been discussed thoroughly. The results findings confirmed that as the strain rate rises, the dynamic characteristics of concrete also escalate. This is explained by the observed variations in DIF, which fall within the ranges of 1.76–2.65 for standard concrete (SC) and 1.28–1.70 for high-strength concrete (HSC). It was also confirming that the sensitivity of lateral inertia and end friction confinement is influenced by both the specimen diameter and strain rate. The lateral inertia confinement in larger diameter specimens significantly increases the DIF. In addition, the presence of end friction at the specimen bar interface also constrains the lateral deformation and significantly increases theDIF_μ≠0, but there was no visible effect of specimen diameter was observed on the DIF_μ=0 of the concrete.