PURPOSE: To enable the repairing and reinforcement of cracked or floating part of concrete, mortar, etc., under low toxic condition in high workability, by injecting a one-pack type epoxy resin injection agent containing a specific ketimine.enamine compound.

CONSTITUTION: A one-pack type epoxy resin injection agent is produced by compounding (A) a ketimine.enamine compound produced by the dehydrative condensation of (i) an amine compound having ≥2 primary and/or secondary amino groups (e.g. 1,8-p-menthanediamine) and (ii) a carbonyl compound (e.g. isobutylaldehyde) to (B) an epoxy resin (e.g. glycidyl ether-type epoxy resin). The injection agent is injected into a cracked or floating part of concrete or mortar, etc., preferably under pressure by automatic injector to effect the repairing and reinforcement of the defects. The amount of the active hydrogen of the component A is preferably 0.5W2.1 equivalent based on 1 equivalent of the epoxy group of the component B.