Study on concrete structure’s durability considering the interaction of multi-factors

• The experiment method considering crossed influence of multi-factors and bracket-type loading device is proposed.
• Carbonation model which includes influence coefficients of multi-factors is set up.
• The carbonation rate is not constant but grows fast in the former period and slows gradually in the later.
• The tensile stress facilitates the concrete carbonation, while the compressive stress inhibits the concrete carbonation.

The durability of concrete’s material and structure is affected by the combined action of multiple factors, and in particular, the effect of stress on the durability should be treated seriously. The quick carbonation experiment of concrete’s material is conducted based on bracket-type loading device and appropriate experimental program in comprehensive consideration of the factors including external loads, environmental corrosion medium, material properties and ages, from which representative factors such as stress levels, CO2, water-cement ratios and carbonation ages are selected. The experimental result shows that concrete’s carbonation rate decreases gradually with time; tensile stress can accelerate the concrete carbonation whereas compressive stress retards carbonation; within a certain range, the greater the water-cement ratio, the faster the carbonation rate is. Carbonation model is presented based on the crossed influence of multi-factors by regression fitting and analysis of the test data. After validated by engineering example, the model is reasonable.