Influence of Friction on the Dynamic Increase Factor of Concrete Compressive Strength in a Split Hopkinson Pressure Bar Test

This study includes the experimental and numerical research conducted to establish a standardized lubrication technique for a concrete split Hopkinson pressure bar (SHPB) test. Concrete SHPB tests were conducted using different quantities of high-vacuum grease, petroleum jelly, and Teflon to determine a desirable lubrication method. Subsequently, follow-up concrete SHPB tests with different specimen dimensions were performed to validate the proposed lubrication method and obtain a dynamic increase factor (DIF) exclusively with respect to the rate effect (that is, pure rate DIF). Furthermore, the pure rate DIF was verified through finite element analysis of the SHPB tests. The experimental and numerical outcomes demonstrated that the frictional effect was elim-inated in the concrete SHPB test when a lubricant more than or equal to 12 mg/cm(2) was applied to the specimen irrespective of the lubricant type.