A ceramic honeycomb structure comprised of at least two separate smaller ceramic honeycombs that have been adhered together by a cement comprised of inorganic fibers and a binding phase wherein the smaller honeycombs and fibers are bonded together by the binding phase which is comprised of an amorphous silicate, aluminate or alumino-silicate glass and the cement has at most about 5% by volume of other inorganic particles. The cement may be made in the absence of other inorganic and organic additives while achieving a shear thinning cement, for example, by mixing oppositely charged inorganic binders in water together so as to make a useful cement for applying to the smaller honeycombs to be cemented.