Durability of Concrete under Combined Impact Environment and Mechanical Load: Analysis of Experimental Studies

Today, there are several methods for predicting the durability of reinforced concrete structures. In most cases, one of the dominant destruction processes is taken into account – either carbonization or chloride penetration. Experimental results and field observations show that this is an unrealistic approach. Therefore, it is necessary to develop a method for determining the durability of concrete under combined impacts, i. e. with the penetration of chlorides into it and mechanical load. The paper describes in detail an experimental method for studying the effect of mechanical load on the penetration of chlorides into the pore space of cement-based materials. A test method is presented that makes it possible to determine realistic diffusion coefficients of chloride ions in concrete under compressive or tensile stress. As a result of the experiments carried out, it has been determined that the combination of mechanical loads and environmental influences can be much more significant than just environmental influence without the influence of mechanical loading. In fact, the service life of reinforced concrete structures depends on many possible combinations of mechanical loads and environmental influences, including freeze-thaw cycles. Thus, cracks formed during freeze-thaw cycling should be taken into account in tests of combined environmental and mechanical stress in order to better understand and systematically describe the effect of such exposure on the durability of concrete. For reliable prediction of the service life of reinforced concrete structures, it is also necessary to take into account the influence of the applied cyclic stress.