Analysis of chloride transport and storage properties of high performance concrete modified by fly ash addition as an effective tool for assessment of its durability

摘要

The effect of fly ash addition on moisture and chloride transport and storage properties of high performance concrete is studied. For comparative reasons, the samples of reference Portland cement concrete without fly ash are analyzed as well. A basic characterization of investigated materials is performed using determination of bulk density, matrix density and total open porosity. Chloride binding isotherms are measured by modified adsorption method. For the determination of chloride transport properties, two different experiments are performed. At first, the chloride transport is characterized by the water and chloride solution absorption coefficients resulting from the standard sorption test. In the second experiment, and moisture diffusivity as function of moisture content, and chloride diffusion coefficient as function of chloride concentration are calculated by inverse analysis. On the basis of obtained material parameters describing the moisture and salt transport and storage, the durability of fly ash modified high performance concrete is assessed and compared to reference material.