Advances in Science and Technology Vol. 135

Abstract: For the creation of underground works such as road and railway tunnels, critical infrastructure facilities, collectors, multi-purpose halls, it is necessary to excavate rock material from the massif. This generates surplus and unnecessary rock material, which in most cases ends up as waste in a nearby stockpile or waste dump. Often this material can meet the quality requirements for construction aggregate. Therefore, this material can be reused as a source of aggregate, thereby reducing construction costs in a circular economy. The article briefly describes the methodology of the evaluation and testing of waste rock from tunnels for various purposes of its reuse as aggregate.

Abstract: Wastes from various industrial processes are used in the construction industry in the production of cement composites, for example as a replacement for part of the cement. In addition to contributing to promoting circularity and reducing the carbon footprint, several waste materials have properties that promote improved durability of the resulting composites due to their pozzolanic properties. This paper deals with testing of the pozzolanic activity of selected wastes from local manufacturing processes such as slag, zeolite, microsilica and fly ash using the thermal analysis method (TG/DSC). The highest pozzolanic activity after 2 days was observed for blast furnace slag, however, after 56 days it was recorded for fly ash and ladle slag. Blas furnace slag and microsilica showed very similar pozzolanic activities evaluated by a comparable amount of unreacted calcium oxide of about 35%.

Abstract: The quality of silica sand used in composite cements is crucial. A significant factor is the dilation of sand grains. In this study, two types of silica sands from related deposits were examined to identify differences in properties, such as grain size and shape, chemical purity (using SEM and XRFS), and their impact on dilation. It was found that the location supplying coarser-grained sand exhibited higher chemical purity but also 19.8% higher dilatation.