Impact of Added Chalcedonite Powder on Selected Concrete Properties

Abstract

In recent times, the interest of scientists in new additives has increased, which can be modified by the properties of concrete mixtures and the parameters of hardened concrete. The PN-EN 197-1:2002 standard permits the use of mineral additives for cement, both as a main component (> 5.0% by weight) and as a secondary component (<5.0% by weight). Particular attention is paid to the problem of managing waste materials. The article discusses the results of laboratory tests on the effect of chalcedonite flour on the parameters of hardened concrete and rheological characteristics of the concrete mix. The addition to concrete mixtures was a chalcedonite meal with a diameter of less than 0.1 μm. It is a waste coming from the mine of broken chalcedonite aggregates. The main component of chalcedonite dust is silica. The rheological properties of concrete mixes, i.e. consistency, density, aeration degree and parameters of hardened concrete, including compressive strength, capillary rise and absorbability. The laboratory tests carried out indicate that the use of chalcedonite powder in the composition of a concrete mix has a positive effect on parameters such as capillary rising and water absorption. The addition of 15% of the meal results in a reduction of the compressive strength compared to the reference concrete by 10% on the 28th day of maturation. The use of a concrete additive in the form of chalcedonite powder can solve the problem of storing and managing waste in the production of broken chalcedonite aggregates. Concrete with chalcedonite meal can be used in places exposed to water, humidity and atmospheric conditions, where the compressive strength parameter is of secondary nature.