231 Investigation of the interstitial pore pressure of saturated concrete under high confinement

The objective of this study is to measure the interstitial pore pressure into saturated concrete under hundreds of Mega-Pascal of confinement. This study is carried out within a more general context aiming to understand the behavior of concrete structures under impact. It is well known that the water saturation in massive concrete structures evolves from quasi-dry state at the surface to reach a quasi-saturated state at the core. Since the response of these structures under impact is highly linked to the state of saturation into the material, there is a suspicious that the pore pressure plays a major effect. This paper presents a new testing technic developed to measure the concrete pore pressure at high confining pressure. This latter is generated by means of a high capacity GIGA press. The new concept consists in implementing a pressure sensor into a water collecting cap. This cap is designed specially to collect water from concrete subjected to mechanical confinement pressure. Experimental results show that concrete pore pressure can reach values of the order of the confining pressure