Analysis of Porous Structure in Autoclaved Materials Modified by Glass Sand

Abstract

This paper describes the use of glass sand in the production of autoclaved bricks. Traditional autoclaved materials consist of SiO2, CaO, and H2O. The purpose of the tests is to analyze the possibility of using glass sand in autoclaved materials and to determine their properties and durability. Depending on the structure, building materials can have porosities ranging from 0% (glass, metals) to over 90% (thermal insulation materials such as aerated concrete). Porosity of materials is directly related to the strength of materials and their density, and further to the thermal and acoustic insulation properties of products used especially for external wall construction, i.e., bricks, concrete, and aerated concrete. This type of silicate brick is formed at a temperature of 203 °C, therefore the dominant phase forming the microstructure is tobermorite, in contrast to the C-S-H phase, which dominates in concretes and which is characterized by a larger specific surface. The nature of pores, their number, appearance and arrangement in the material can be studied using computer techniques (SEM, XRD, computed tomography, porosimetry). Computed tomography (micro-CT analysis) showed that the number of voids in the material modified by glass sand is about 20% in relation to the weight of the product. The density of the product with glass sand was determined to be 2.2 kg/dm3.