Wettability and surface free energy of granodiorite, dolomite and recycled ceramic aggregate

The study of wetting properties and surface free energy (SFE) of granodiorite, dolomite and recycled ceramic aggregate was presented in the paper. Every tested aggregate had different wetting properties. Based on the SEM study, the microstructure was shown. Wetting properties of various aggregates were determined by measuring the contact angle of their surface using water as measuring liquid. Many factors influence the contact angle, including physical and chemical homogeneity, roughness and surface contamination, type of measuring liquid, drop size of measuring liquid, humidity, ambient temperature, etc. Measurements were carried out 0 minutes after the time of application of the drops. The total SFE was determined using the Neumann method. Analyzing examination results it can be noticed that the values of contact angles depends on the absorbability of aggregate and smoothness of its surface. The results of contact angle measurements proved that all contact angles for ceramic aggregate were lower than contact angles for dolomite and granodiorite. That causes the total SFE for ceramic aggregate was higher than SFE for dolomite and granodiorite aggregate. The highest contact angle was noticed for granodiorite. The smallest contact angle with water was obtained by ceramic aggregate. This is due to physical characteristics of this aggregate. Ceramic aggregate is characteristic of the high absorbability. This indicates an increased wettability and increased adhesion properties.