Roadway Slab Longevity Evaluation of Highway Reinforced Concrete Bridges in Conditions of Cyclic Loading and Adverse Effects of the Environment
During operation, the roadway slab of reinforced concrete bridges is subjected to cyclic loading from vehicle static and dynamic effect with the active impact of the environment. More often, the combination of these reasons causes crack formation in the construction material and its destruction. Now due to the lack of long-term, regular studies and observations, there are no uniform evaluation criteria of the crack formation and slab destruction because of mutually developing destructive processes. The mechanism for crack formation evaluation and the concrete destruction criterion parameter of the roadway slab with the joint effect of the external environment and stressed state from moving load is suggested. As an example of the parameter, the concept «crack density», i. e. overall crack lengthway and crosswise elongation on an area of 1 m<sup>2</sup> is used. The criterion analysis of the roadway slab destruction degree depending on the density of the crack propagation compiled on the basis of systematic observations of the bridge group operating in various regions is given. Solutions to restore construction integrity during operation are suggested.