IMPACT OF THE GLUE LAYER PROPERTIES ON THE STRESS-STRAIN STATE OF THE GLUE ANCHOR FOR THE STEEL ROD IN CONCRETE

Abstract

The article deals with the distribution of stresses and displacements along a steel anchor fixed in concrete with a polymer binder - an acrylic compound. It was established that the maximum values of tangential, radial, and circular stresses, which more fully characterize the operation of the connection, change depending on the strength characteristics of the adhesive layer and its thickness according to the exponential law. The obtained results of stress at any point of the adhesive joint allow us to propose a methodology for the design of steel rods in concrete fixed with polymers. As a result of solving the problem of the stressed-strained state of the anchor connection on acrylic adhesives, equations were obtained for determining stresses and strains at any point. As a result of the analysis of the obtained dependencies, the following conclusions can be drawn. When calculating the strength of anchor joins on acrylic adhesives, it is necessary to take into account the maximum values of tangential, radial, and circular stresses. In order to calculate the strength of the join, it is necessary to know the strength limit at uniform separation of the glue from the metal surface, as well as at shear for the glue-metal contact. Tangential and normal stresses in the adhesive cylinder and at the adhesive-concrete interface decrease with an increase in the modulus of elasticity of the acrylic adhesive. But this leads to an increase in normal axial stresses in the part of the anchor embedded in concrete and radial stresses at the glue-anchor and glue-concrete contacts. The elasticity modulus of the glue layer is smaller than the elasticity modulus of concrete and metal. Therefore, the adhesive distributes the stresses that arise from the application of the pull-out force between the anchor and the concrete massif. This is explained by the fact that the pull-out stresses from the anchor are completely transferred to the adhesive layer and then to the concrete. The main vector of tangential stresses does not depend on the ratios of the elasticity modulus of the materials which form the anchor join. The thickness of the adhesive layer has a slight effect on the stress in the glue-anchor contact, but significantly on the stress in the glue-concrete contact.