Effect of basic pumice on morphologic properties of interfacial transition zone in load-bearing lightweight/semi-lightweight concretes

The objective of this research is to determine the effect of basic pumice on morphologic properties of interfacial transition zone in load-bearing lightweight/semi-lightweight concretes. In this respect, it has been researched how the chemical and physical structure and the volumetric ratio of basic pumice affected the following three morphologic properties of interfacial transition zone: compactness, width and physical adherence. In accordance with the stated purpose, 15 concrete serials with various properties were produced using basic pumice as aggregate and 670 images were taken from the samples collected from these serials via scanning electron microscope (SEM). Semi-analytical detections were performed based on non-generalizing numeric data obtained in conclusion of the determination of grain limits in these images and comments on visual analysis. In accordance with these detections, it has been concluded that the basic pumice has a high level of potential to contribute to the morphologic properties of interfacial transition zone.

Research highlights
► Due to its chemical structure, basic pumice has caused a very strong hydration development and this has positively affected the morphologic properties of interfacial transition zone.
► The physical structure of basic pumice caused the formation of a physical adherence level which could not be obtained through the use of ordinary and artificial lightweight aggregates.
► The morphologic properties of interfacial transition zone get better when basic pumice was used at lower volumetric ratios.