الفهرس 
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Abstract
Repair and strengthen applications are routine tasks in building constructions. Engineers need to know the mechanical characteristics of the available repair products and their proposed substrates before an assessment can be made and suitable repair system chosen. This research presents an experimental study to evaluate the behavior of some locally available materials that are used for repairing concrete.
Since 1970, there was one available choice to repair concrete using cement mortar and concrete as repairing materials. As a result of the development of the petrochemical industries, new materials started to appear and several researches were carried out on them to show the availability of using the new materials in repairing of concrete. Epoxies, polyesters, and other polymers such as sryrene butadiene and acrylic are new repairing materials that were appeared in the Egyptian market at the last few years.
Aim of this study is to shed light on concrete repair substances and compare their physical and mechanical characteristics through testing according to available standard specifications and compare between substances of same origin according to their application on repair, such as bonding agent, patch repair or fixing reinforcements, in an attempt to reach better decision on best substances for repair methods regarding efficiency and price.
Twenty-five commercial materials that are produced by five local companies were selected and tested.
The physical and mechanical properties, such as compressive strengths using 40mm and 50mm cubes, flexural strength and flexural modulus tests were carried out on each substance of repair mortars. Slant shear tests were carried out on bonding agent substances adding to their strengths and flexural modulus of elasticity properties, tension and shear tests were carried out also on steel fixed into concrete using steel fixing substances which added to their other properties.Compressive, flexural strengths and flexural modulus were carried out on five cementitious repair mortars, five epoxy repair mortars, five polymer modified mortars, five epoxy bonding agents, two epoxy fixing mortars and three polyester fixing mortars.
Slant shear tests were carried out on five epoxy bonding agents, four polymer bonding agents, four polymer bonding agents mixed with cement and water.
Steel tension and shear tests were carried out on five epoxy mortars and three polyester mortars to determine their effectiveness as steel fixing agents into concrete.
As repair applications, three cylindrical columns were repaired after scratching without using bonding agent, three columns were repaired with using bonding agent, three columns were repaired after fixing studs in them without using bonding agent and three columns were repaired after fixing studs in them using bonding agent
Also, prisms damaged at two levels, were repaired by market mortars, three prisms damaged at level I were repaired using bonding agent, three prisms damaged at level 1 were repaired without using bonding agent, three prisms damaged at level 2 were repaired using bonding agent and three prisms damaged at level 2 were repaired without using bonding agent.
Test results show that epoxies are good materials as a repair mortar, as a bonding agent and as steel fixing material but they are bad workable materials and very expensive, polyesters are good steel fixing materials, polymer fibrous mortars are good mortars for concrete repair, acrylic is bad material for use in repair mortars or as a bonding agent and limited shrinkage cement mortars still the best choice for concrete repair.