Evaluation of Clinker Microstructure Changes Resulting from Different Subsoil Contacts After Long-term Exposition to Polish Climate Conditions

A face wall is defined as an element applied inside or outside which should have an attractive look. The achievement of expected results is very difficult. Usually, during the first years of exploitation efflorescence appears, covering mostly clinker surface. This is primary efflorescence which should disappear within the first year of exploitation. Long-term observations led by the author on real objects indicate that this period is definitely longer, and efflorescence change depending on seasons of the year. The essential influence has the wall and subsoil contact area. This is an area especially endangered with rain and soluble compounds contained in water. The cyclic character of these changes influences the clinker microstructure. This paper deals with clinker microstructure changes resulting from ten years of exposition to external climate. There are three cases of wall and ground contact: a tight concrete band, humus layer, and gravel filter layer. The tests were performed on a field station located at the University of Science and Technology in Bydgoszcz. Three types of clinker walls with different mortars were analyzed. Six samples of bricks designed for wall erecting were taken as initial material for microstructure evaluation. The tests were led on 5 mm thick face layer of bricks. Based on observation there were indicated areas of the biggest efflorescence intensity. Microstructure evaluation was done using mercury porosimetry method. The results obtained were used for comparative analysis of meso- and macropore share changes in clinker after ten years of functioning in external environment. These tests let us indicate the best solution taking into account the wall and ground contact.