Ultrasonic pulse velocity as a non-destructive measure for the projectile impact resistance of cementitious composites across a wide range of mix compositions

Abstract

This paper presents an investigation on the applicability of using ultrasonic pulse velocity (UPV) as a non-destructive measure for characterizing high velocity projectile impact (HVPI) resistance as well as physical/mechanical properties of cementitious composites across a wide range of mix compositions. Ultra-high performance concretes (UHPCs), engineered cementitious composites (ECCs), concretes, mortars and cement pastes with compressive strengths ranging from 34.2 MPa to 220.2 MPa and elastic moduli ranging from 17.1 GPa to 104.2 GPa are considered for investigation. Projectile impact resistance of cementitious composites is evaluated in terms of the depth of penetration (DOP) and equivalent crater diameter (ECD). Physical/mechanical properties, including compressive strength, static and dynamic moduli of elasticity, density, hardness, splitting tensile strength, compressive and flexural toughnesses, are investigated. The UPV is found to be a promising non-invasive and non-destructive measure for the DOP characterization, since both the UPV and DOP are governed by the weighted properties of underlying constituent materials (e.g. matrix and fine/coarse aggregate). In comparison to the DOP, the correlation between the ECD and UPV is relatively weak. The results indicate that there exists a strong correlation between the UPV and the elastic modulus/density/hardness of cementitious composites. It is also found that commonly used two-phase composite models can predict the UPV of concrete with good accuracy.