In the aim to improve the physical properties and the mechanical performance of the confinement matrix of spent of use Ion Exchange Resin (IER) considered among the radioactive waste of low and medium activity of long-lifetime, various formulations of the cementitious matrix based of different percentages of zeolite raining form 2% to 10% by weight of cement with a step of 2% have been developed. The physical properties (compactness) and the mechanical performance (the compressive strength) of the new cement- zeolite matrix have been investigated.

The obtained experimental results from the different formulations elaborated showed that the partial substitution of cement by the zeolite improves significantly the physical properties and the mechanical performances of the last one, this is due mainly to the pozzolanic properties of zeolite related to their reactive SiO₂ and Al₂O₃, Which react with Ca(OH)₂, released during the hydration of cement and transforming it into aluminates and gels C-S-H. In consequence, the microstructure of the hardened cementitious matrix has improved; its compactness and its mechanical resistance of compression were increased also.