Design of a Controllable and Repeatable Material for Field Penetration Tests

To enhance predictions of projectile penetration depths and develop a new scaling law, a repeatable target material is crucial for advancing penetration mechanics understanding. Traditional concrete, often used in penetration tests, is controllable in terms of shape and size and cost-effective. However, concrete is heterogeneous and experiences shrinkage during curing, with variations in uniaxial compression strength exceeding 25% even with consistent formulations, challenging the repeatability needed for such tests. Conversely, plaster-based materials provide superior repeatability, controllability, and scalability. By adjusting the mixtures of plaster and Portland cement, their strength can be regulated from a few megapascals to over 50 MPa. We found that Hydrostone could be a potential good material with repeatability, controllability, scalability, economy, and compatibility. It showed uniaxial compression strength of 42.0 MPa, comparable to or greater than concrete, with an optimized uncertainty in strength around 5%. Triaxial compression tests further revealed a maximum yield stress of 53 MPa at a normal stress of 45 MPa. These findings indicate that plaster-based materials are promising for controllable and repeatable penetration tests, with implications for penetration simulation models.