The invention relates to a cement for the cathode blocks of electrolytic cells, e.g. Hall-Heroult cells used for the production of aluminum. The cement comprises a carbonaceous aggregate of particle size smaller than 48 Tyler mesh, a curable water-soluble liquid polymeric resin (preferably a phenol-formaldehyde resin), water and normally a curing agent for the resin. The water is used in such an amount that the proportion of the resin can be reduced without adversely affecting the viscosity of the cement at ambient temperature. The cement carbonizes when the cell is used and has a linear shrinkage of less than 5%, which reduces the tendency of the carbonized cement to crack during operation of the cell.
