Image analysis in determining pore size distributions of concrete

An analysing system where modern image analysing techniques and the computer-aided data processing have been utilized is presented. Principles of analysing the air porosity of concrete are described as an example of application. In the analysis the 3-dimensional number-based and volume-based distributions as well as the cumulative presentation of the average distance between pores are determined. Moreover the principles of calculating some characteristic values of porosity are presented. The analysing process consists of three parts corresponding to the progress of the computer programme. 1) Measurement stage where the 2-dimensional number-based distribution of pores is determined by image analysis. 2) Processing stage where the 2-dimensional distribution is transformed into a 3-dimensional distribution. 3) Output stage where the 3-dimensional number-based distribution and some derived distributions are plotted and calculated pore parameters are printed. The analysis proceeds automatically from stage to stage. The total analysis time is about 35 minutes.