No abstract

Traditional decorative cements are made on the basis of white cements and the demand for them is constantly growing. But such cements have all the disadvantages of clinker cements, namely, high energy intensity and high price. An alternative may be slag-alkali cements having higher physical and mechanical characteristics and lower price. Therefore, these studies were aimed at choosing such additives that would have the maximum whitening properties and would enhance the stabilization of bleaching processes during hydration and hardening of slag in the presence of alkalis, to determine the simultaneous effect of three additives on the whiteness and physical-mechanical characteristics, as well as to determine the optimal the content of these additives in slag-alkali decorative compositions. In this work, as a result of the studies performed, the possibility of obtaining effective slag-alkali white cements as the basis for the production of decorative concrete with acceptable economic characteristics is proved. The influence of each of the bleaches on such characteristics of decorative slag-alkali cements as strength, setting time, whiteness is established. Methods for optimizing compositions are identified.

The construction industry is demanding more and more quality decorative cements. The demand for them and the requirements for their performance are constantly growing. But since decorative cements are based on white Portland cement, their production is associated with the shortcomings of the production of all clinker cements – low environmental friendliness, high energy consumption and high prices. They are not always able to provide decorative ecological and comfortable coatings with increased performance. In addition, many countries do not produce it and have to import it. An effective alternative to decorative clinker cements can be decorative slag-alkaline cement obtained from industrial waste. It also provides a number of special properties – a wide range of colors, color fastness, high strength, high adhesion, durability and many others. But the problem associated with the use of slag-alkaline cements as decorative cements with high whiteness (≥ 70%) is the instability of the chemical composition of the slag and, first of all, the different presence of iron oxides in it. The paper shows the regularities of the influence of the chemical composition of blast-furnace slags on the whiteness of an artificial slag-alkaline stone. A new method for determining the whiteness of hardened materials is proposed. Possibilities of obtaining decorative alkali-activated cements with a wide range of whiteness – from 70 to 97% are shown.