PURPOSE: To obtain a concrete compsn. which quickly cures and has improved thermal expansion coefficient and elastic modulus by compounding a specific epoxide, a specific curative contg. a polyethylene glycol diamine, and a specific accelerator contg. piperazine.

CONSTITUTION: This compsn. is prepd. by compounding an aggregate with a vicinal polyepoxide having on average at least 1.8 reactive 1,2-epoxy groups per molecule, a stoichiometric amt. of curative contg. triethylene or tetraethylene glycol diamine, and an accelerator contg. an effective amt. of piperazine. An example of a useful polyepoxide used in a wide range is a resin-like epoxy polyether obtd. by reacting an epihalohydrin (e.g. epichlorohydrin) with a polyhydric phenol or alcohol.