An Improved Technique for Determining the Equation of State of Concrete and Geological Materials

Concrete is used extensively for building defense and civilian structures as it is highly damage resistant, inexpensive, durable and can be cast into any form. Concrete can be subjected to a variety of extremely large stress events. The survivability of concrete structures could be enhanced if the mechanical behavior of concrete at elevated stresses and strain rates was known. This information can be obtained from the equation of state of concrete. Typically, the equation of state is obtained from shock wave tests. This approach can be expensive and time consuming, especially if the magnitude of the strain and the strain rate need to be controlled. An alternative technique, in this proposal, is to determine the equation of state of concrete and geological materials by measuring the elastic properties as a function of applied load and eliminates the need for sample constraint to prevent shear failure. With the knowledge obtained from the equation of state, it will be possible to enhance the survivability of defense and civilian structures if they are exposed to high strain events.