Like polyurethane is also a two-component system having a base resin and a reactor or curing agent. Base resin is obtained by dissolving bis-phenol A flakes in epichlorohydrin. This base is available in various viscosity ranges to suit different application conditions. The curing agent is an amine/polyamine aliphatic or aromatic, or an amine-adduct for general applications and polyamide or an amino-amide for coating purposes. After mixing base and reactor components the resultant viscous liquid or paste if some fillers are added to it can be brush applied like a paint or trowel applied like a mortar.
Here also epoxies not withstanding the alkalinity of concrete and the concrete needs to be acid washed and neutralised, which the civil engineers hated. Here again the coefficient of thermal expansion of concrete and epoxy being different the compatibility of epoxy in waterproofing exposed concrete surfaces such as roofs became limited. Later the use of epoxy in waterproofing was discarded. But epoxies have come to stay in civil engineering industry as bonding agents, floor & wall coatings, coatings for food processing units, operation theatres and computer and pharmaceutical industries.