Investigations of concrete surface nanomorphology and microhardness

Abstract

During the last decade great attention is paid to nano modification of concrete materials in order to achieve new exploitation properties. Addition of nano modifiers to concrete paste and investigation of modified concrete materials requires complex morphological, physical and chemical analysis. Modifying the concrete with nanostructures, volumetric and surface distribution is determined by nano mechanical properties and in order to evaluate these modifications new progressive analytical methods are required. In this work modified concrete (alumina cement with liquid glass and metallurgical slag waste) was investigated by atomic force microscope (AFM) NT-206. AFM has proved to be a powerful tool for investigating the surface structure of hydrating cements, the changes in cement paste surface morphology in response to exposure to relative humidity, the carbonation process of cement phases, and the local adhesion forces evaluation. The overall changes in mechanical properties were measured by Rockwell hardness tester Wilson-Wolpert 500MRA S. Obtained values were later converted to Vickers hardness using conversion tables. Used analysis methods allowed comparing changes in quality of concrete blocks on macroscopic level and investigating changes in morphology and distribution of nanostructures depending on addition of nano modifiers and amount of concrete components.