Influence of loads that change the sign on the adhesion of modified gypsum cement concrete to building structures

Abstract

The results of the study of the adhesion strength of gypsum-cement concrete modified with iron compounds under the conditions of alternating loads and alternating temperatures are presented. Prolonged operation of buildings and structures of most Ukrainian enterprises necessitates the restoration of their operational properties. Particularly difficult is the question of restoring the performance properties of concrete structures exposed to water or other liquids. Another important factor influencing the final properties of the protective coating, especially the strength of its adhesion to the concrete of the structure being repaired, is the alternating loads arising in this coating due to technological equipment or explosive work in adjacent quarries observed in conditions of the Kryvyi Rih iron ore basin. The analysis of literature data showed that in the conditions of alternating mechanical influences it is most rational to use systems based on gypsum-cement binder, modified with a complex additive, which is a system "mineral complex based on iron - polyalcohol". the adhesion strength of gypsum cement stone and, consequently, concrete with the base, increasing the time of exposure to negative temperatures and the application of alternating load leads to a decrease in adhesion strength of repair concrete to the surface of the building under repair, reducing the impact of alternating loads and ambient temperature on system properties "Repair concrete - repaired structure" is possible by introducing into the repair concrete complex additives, which is a dispersed system "mineral complex based on iron - polyalcohol", which improves the quality of repair work by increasing the strength of contact between system, with the optimal ratio between the components of the complex additive mineral complex based on iron: "polyalcohol" is 10: 0.5 with its total content of 20% by weight of the system Keywords: gypsum cement concrete, strength, iron compounds, polyalcohol.