Features of concrete strength control with a carbonated layer

In the reinforced concrete structures maintenance process of various purposes, there periodically arises a necessity for inspections to establish the current consumer properties, which change over time. One such property is the durability of concrete. The assessment of the actual durability of hardened concrete has always been and remains one of the key points in the life cycle of concrete and reinforced concrete structures, both at the stage of bringing into operation new facilities and at various ages during operation. When controlling the durability of concrete in operational structures, there will almost always be an external carbonated layer of concrete on the tested area, the depth of which depends on the age of the structure and external conditions. Assuming a difference in the physical and mechanical properties of the carbonated layer compared to the intact main concrete, one can conclude on the necessity to consider this circumstance for a correct durability assessment of the main concrete in the structure. The aim of this paper is to review domestic and foreign experience in testing concrete using the shear test method, analyze approaches to assessing the durability of carbonated concrete, and develop a testing scheme that takes into account various physical and mechanical properties of both carbonated and intact main concrete. As a result of this work, the author has analyzed and summarized the evaluation criteria for complete carbonation and established its boundaries, analyzed the approach to determining the durability indicator of carbonated concrete, and proposed a testing scheme using the shear test method, which allows for calculating the strength indicator of intact concrete unaffected by carbonation.