Development length of steel reinforcement with corrosion protection cementitious coatings

The bond strength and development length of steel reinforcing bars coated with cementitious capillary crystalline waterproofing materials were evaluated using a modified pull-out test method. The coatings possess self-healing capabilities and are characterized by a novel eka-molecular sieve type structure to prevent moisture penetration. Following a study on corrosion protection, in which the coating showed a great promise, it was decided to investigate the effect of the coating on bond strength. A self-reacting inverted T-shaped beam was designed to simulate the stress conditions of flexural structural members. Six T-beams were fabricated, each of which contained eight rebar test samples. Tests were conducted at approximately seven days and at three months after casting to investigate curing effect on bond. Although the bond strength of the coated samples were reduced compared with the uncoated bars, theoretical development lengths obtained from current concrete design code equations were sufficient to reach the yield strength of the bars.