If you have compressive strength of concrete then you can find other parameter. If you have test data for the compressive strength of the concrete, you should use that data. It is important to note that the compressive strength of concrete is not the only material property that affects the behavior of concrete in the CDP model. Other important properties include the tensile strength, fracture energy, and tensile softening parameters. These properties should also be determined based on the specific type of concrete being modeled and the available data.