Effect of Type and Dosage of Activators on Strength of Repair Concretes

Abstract

The different effect of chemical activators on mechanical properties and microstructure of cement-base repair materials were investigated. The microstructure of repair concrete was also analyzed by using scan electronic microscope (SEM). Test of mechanical properties indicate that the optimum chemical activator suitable to repair concrete with nearly 30% mineral materials replacement of cement is the type J-B, and the optimum addition is 5% dosage by weight of binders. The presence of chemical activator J-B increase the early strength and exert significantly advantageous affect on the later strength. Measurement of microstructure indicates that the surface of fly ash particle can be seen obvious pozzolanic reaction, and this is due to the presence of chemical activator which accelerate the pozzolanic reaction and densify the mortar pore structure.