DEPTH OF THE CONCRETE COVER SUBSTANTIALLY AFFECTS THE MAXIMUM STRESSES OF THE BOND BETWEEN CONCRETE AND STEEL

Abstract

The article gives the results of the experimental researches of the bond between steel and high strength concrete. The analysis of the impact of the concrete cover on the boundary stresses of the bond between steel and concrete was carried out. The analysis of regression equation structures shows the absence of the linier impact of the bar diameter on the boundary stresses of the bond f_b . The obtained mathematical model allows analyzing the impact of factors, that were investigated on the boundary stresses on the contact surface of steel and concrete. The analysis of the results of the experimental researches speaks  that the depth of the concrete cover  has a significant impact on the boundary bond stresses. The maximum bond occurs at the largest concrete cover, while the minimum bond being at the least. The longitudinal cracks were formed along the longitudinal actions of the bars as a result of the wedging moment of the transverse actions, located at the angle to the direction of pulling out the bars. It has been experimentally proved that the depth of the concrete cover substantially affects the maximum stresses of the bond between concrete and steel and the character of destructing prisms.