High performance concrete "HPC"-field experiments and production

This investigation involves production and penetration tests of high performance concrete (HPC). A total of 62 penetration tests were performed seperated into six test series. The compressive strength of the targets varied between 30 MPa and 220 MPA. At one occasion concrete with a strength exceeding 250 MPa was produced. In the penetration tests, three different projectiles with a diameter of 43 mm, 75 mm and 152 mm were used. The results from the production tests show that concrete with strengths up to and including 150 MPa enabled large scale production. Experience from these tests in field conditions show the difficulties in large scale production of concrete with a compressive strength exceeding 180 MPa due to its viscosity. The penetration tests clearly show that an increase in concrete strength enhances the penetration resistance of concrete structures. However, the tests indicate that concrete strengths exceeding 120-160 MPa result in relatively moderate enhancements of the protective level. Reinforcement also increases the penetration resistance of concrete. The volume fraction, however, needs to be around 6% in order to obtain a reduction of 25% in penetration depth. The effects of different impact velocities were also studied. Relatively large penetration enhancements were observed with an increasing projectile velocity. The tests showed that the results may be influenced by the target dimensions. In order to avoid boundary effects the target diameter may need to be around 15 to 20 times the penetrator diameter.