Determination of the dynamic modulus of elasticity of UHPFRC by the impulse excitation technique and comparative analysis with the static modulus

Ultra-high-performance fiber-reinforced concrete (UHPFRC) is a cementitious composite characterized by high mechanical strength, low porosity, enhanced durability and ductile behavior, enabling the design of more slender and lightweight structural elements. These attributes make it a promising alternative to conventional concrete in specific applications, with potential technical, economic, and environmental benefits. In this context, the present study investigates the dynamic modulus of elasticity of UHPFRC with different volumetric fractions of steel fibers using the impulse excitation technique, which is based on the determination of the specimen's natural frequencies. This technique stands out as a non-destructive, fast and cost-effective approach for evaluating the mechanical properties of concrete. In parallel, static tests were carried out to determine the static modulus of elasticity, allowing a comparative analysis between the results obtained from dynamic and static methods. Finally, the study assesses the applicability of equations proposed in the literature to estimate the dynamic modulus from the static modulus, contributing to the validation of predictive models for UHPFRC.