Peculiarities of structure and composition of boundary layers of concrete and fiber with modified surface

The purpose of the research is to study the microstructure and chemical composition of the boundary layers of concrete and fiber treated with anticorrosive and anchoring compositions and their influence on the mechanical properties of steel-fiber-reinforced concrete. Using electron microscopy and micro-X-ray analysis, it has been found that the treatment of steel fiber with an anticorrosive composition based on zinc phosphate and orthophosphoric acid, and also with an anchoring composition modified with white clay, leads to the chemical bonding of the cement stone of concrete to the surface of the fibers. The treatment of the surface of the fiber with a clay-modified anchoring composition allows the formation of a mechanically strong layer that combines the contacting phases of the concrete cementitious cement and the anchoring coating on the fiber. The use of the anchoring composition leads to the formation of intermediate layers from the interaction products of the coating components on the fiber and the cement concrete stone, which combine the contacting phases. The strength of the contact zone of cement stone and the strength of its chemical bonding with the anchoring composition on the surface of the fibers makes it possible to pinch the steel filament along the entire length, minimizing the possibility of unobstructed stretching of the fiber under the action of loads, which leads to an increase in the strength of the dispersed reinforced concrete.