A program of thirty five samples starting at year 2002 was prepared with the same steel and the slabs dimension were 50 cm width 14 cm thickness and 240 cm span length, bottom steel included five bars with diameter 13 mm and top steel with 10 mm width, water to cement was 0.56 and the mixing water was with chloride concentration of 3% percent of the cement weight. All slabs were exposed to laboratory temperature, spread daily with water concentration 3% of chloride and the steel on slabs was connected to the electronic to accelerate corrosion process. Three levels of percentage corrosion were expected depending on the current passing in the circuit, some slabs were repaired and strengthened by removing the steel covers 10% corrosion at year 2002 and others (30% - 50%) at year 2004. The slabs group (L) 10% corrosion were tested at year 2004, both Group (M) with 30% corrosion and Group (R) with 50% corrosion were tested at year 2011. Five repairing and strengthening techniques were suggested, crushed stone mix (CSM), ready mixing (RM), crushed stone mixing with steel fibers (CSM+HF), crushed stone mixing steel (CSM+RS) and ready mixing with additional new reinforcing (RM+RS), which are usually used in structure maintenance. The obtained results show that the corrosion for steel was affected by maintenance process and all techniques didn't stop it totally. The mortars (CSM, CSM+F, RM) re-alkalized the areas where the contaminated concrete was removed and re-passivated the steel surface. Due to the reduction in the cross section area of main steel, the slabs had less ultimate strength and more ductility of the steel reinforcement, which results in wider resulted cracks than the other slabs strengthened with steel reinforcement. The outcome indicates that the slabs strengthened by Reinforcing Steel in both CSM and RM layers undergo to the higher load until cracks appear, that leads restoration of its efficiency of 70% to 95% depending on the degree of the corrosion rates.

Full text: IJEIR-1330_final.pdf