Automatic quantification of phases and mechanical characterization of materials based on Portland clinker modified with silica and alumina additions

Actual image analysis software allows the automatic quantification of the different main phases present in Portland clinker. This work studies, by optical microscopy analysis, the modification of porosity and relative amount of phases existing in plain clinker when increasing silica and alumina proportions. The compositions were dry mixed in a laboratory ball mill during 30 min. In all cases three different amounts of additions (3, 6 and 9 wt.%) were chosen. The different mixes were pressed by isostatic pressing (in wet bag) at 180 MPa. The sintering was carried out in air at 1400 °C during 30 min. All materials were polished, without etching, to reach the best contrast between porosity and material to analyse the level of porosity. The samples were etched with a mix of acetic acid and ethanol or hydrochloric acid to quantify the relative amount of main phases of materials. The obtained results were correlated with mechanical properties as bending strength and hardness.