Epoxy-formulations for the coating, repair and structural enhancement of concretes

A “tailored” series of synthetic poly-alkylene-poly-amino-methylolic (P.A.M.) curing agents for epoxide (DGEBA) resins is presented; P.A.M. products were obtained by substituting some of the hydrogen atoms of the aminic functions of an aliphatic poly-amine with methylolic groups (-CH2OH). The viscosities of the fluid epoxy-P.A.M. formulations (before the onset of the curing reaction) were determined at room temperature. Mechanical and creep properties, permeability to carbon dioxide and water of the cured formulations were determined, as well as their adhesion to different concretes; the durability of the resin – concrete joints (U.V. irradiation, freezing-thawing) as well as their crack-bridging ability were also tested. Experimental tests were also carried out for the structural repair of fractured concrete specimens by means of a fibreglass composite with the best experimented epoxy matrix. The evaluation of the chemical structure of the cured epoxy formulations allowed the interpretation of their different behaviours as products for the protection and repair of concrete structures.