Effect of addition carbon and glass fibers on bond strength of steel reinforcement and normal concrete

الملخص EN

The concept of composite materials using fibers as reinforcement is not new.

The aim of composing materials is to improve some properties of the original materials.

In civil engineering, fiber reinforced concrete was one of the topics of interest.

Using fibrous concrete in reinforced concrete structures arises a question of how does it affect the bond strength between the concrete and reinforcing steel bars.

Thus, the present experimental study are carried out to have a clear understanding of the bond strength between normal concrete with two selected types of fibers which were carbon and glass fiber and steel reinforcing bars.

Forty five pullout cubic specimens of size 150mm were fabricated and tested to serve that purpose.

They were divided into five groups to study the effect of some selected parameters such as, type of fiber (carbon and glass),reinforcing bar diameter (12mm, 16 mm and 20 mm)and fiber to cement ratio (f / c) by weight(0.75 % and 1 %).

Also, three concrete cubes having the same size of the pullout specimens from each concrete mix were tested in compression to find their compressive strength.

It was found that the addition of glass fiber with bar diameter = 16mm has much effect in enhancing bond strength than that enhancement accrued by addition of carbon fiber, the bond strength increases by about 13.6 % and 4.5 % with the addition of 0.75 % and 1 % glass fiber.

On the other hand, the bond strength increases as bar diameter decreases.

The addition of the carbon or glass fibers increases the bond strength for specimens with smaller bar diameter and vice versa and the fiber(either glass or carbon) to cement ratio of 0.75 % give higher bond strength than that of 1.0 %.