Analysis of microporosity and setting of reactive powder concrete by proton nuclear relaxation

The proton spin-lattice relaxation measured at several frequencies leads to a resolved distribution of four Tli for reactive powder concrete (RPC). The typical Tli frequency dependences are quantitatively interpreted by a biphasic fast exchange model and a proton nuclear relaxation of hydrated paramagnetic ions at the surface of the pores. This leads to an estimation of the pore sizes. We present the first application of this nuclear relaxation method to follow in situ the kinetics of the hydration and setting of such material.