Fly ashes, from an extensive database showing extremes in ratios of major oxides, are considered as potential raw meal ingredients for preparation of sulfoaluminate cements. Simple algorithmized, essentially Bogue-like, computations are performed in order to create a link between the chemical composition of raw meals and their mineralogical composition, as expected to result from their burning. The computations refer to a set of three-component raw meals, all containing limestone and gypsum but differing in the kind of fly ash introduced as the third raw meal component. The individual raw meal compositions are identified in computations, yielding three phase products, composed of C₂S, C₄A₃S; and C₄AF. The content of each phase is within the following limits: C₂S, 60·7–83·4 wt%; C₄AS, 4·2–27·2 wt%; and C₄AF 2·67–30·5 wt%. As a result, fly ashes are thus convenient raw sources for production of sulfoaluminate cements. Of special interest are fly ashes low in SiO₂/A₂O₃ or SiO₂/(Al₂O₃ + Fe₂O₃) ratios, providing clinkers with the preferred proportions of the mineral phases.

This article describes utilization of a cement kiln bypass dust utilization as an added component in a hydraulic road binder. Three experimental binder mixes (BM1–BM3) with variation in the composition of the main constituents (cement clinker, ground limestone and ground granulated blast furnace slag) and constant content of bypass dust (10%) were prepared under laboratory conditions. The properties of binder constituents, fresh experimental binder mixes and hardened specimens were tested according to STN EN 13282-2 for a normal hardening hydraulic road binder. The physical and chemical properties of all binder mixes (fineness: +90 µm ≤ 15 wt.%; SO₃ content: <4 wt.%) met the standard requirements. The bypass dust addition led to an increase in the water content for standard consistency of cement mixes (w/c = 0.23) and to a shortening of the initial setting time for two experimental blended cement pastes (BM1 and BM3) compared with the value required by the standard. Only BM2 with the lowest SO₃ content (0.363 wt.%) and the highest percentage of granulated blast furnace slag (9.5 wt.%) and alkalis (Na₂O and K₂O content of 5.9 wt.%) in the binder mix met the standard value for the initial setting time (≥150 min). The results of compressive strength testing of experimental specimens after 56 days of hardening (59.2–63.9 MPa) indicate higher values than the upper limit of the standard requirement for the N4 class (≥32.5; ≤52.5 MPa).

The article deals with the study of the effects of alternative fuels and raw materials on the cement clinker quality. The clinker quality was expressed by the content of two principal minerals alite C₃S and belite C₂S. The additions of alternative fuels ashes and raw materials, in principle, always increased the belite content and conversely reduced the amount of alite. The alternative fuels with high ash content were used such as the meat-bone meal, sewage sludge from sewage treatment plants and paper sludge and the used alternative raw materials were metallurgical slags - granulated blastfurnace slag, air cooled blastfurnace slag and demetallized steel slag, fluidized bed combustion fly ash and waste glass. Meat-bone meal, sewage sludge from sewage treatment plants and paper sludge were evaluated as moderately suitable alternative fuels which can be added in the amounts of 2.8 wt. % addition of meat-bone meals ash, 3.64 wt. % addition of sewage sludge ash and 3.8 wt. % addition of paper sludge ash to the cement raw mixture. Demetallised steel slag is suitable for production of special sulphate resistant cement clinker for CEM I –SR cement with addition up to 5 wt. %. Granulated blastfurnace slag is a suitable alternative raw material with addition 4 wt. %. Air cooled blastfurnace slag is a suitable alternative raw material with addition 4.2 wt. %. Waste glass is not very appropriate alternative raw material with addition only 1.16 wt. %. Fluidized bed combustion fly ash appears not to be equally appropriate alternative raw material for cement clinker burning with less potential utilization in the cement industry and with addition 3.41 wt. %, which forms undesired anhydrite CaSO₄ in the cement clinker.

The article deals with studying the antimicrobial efficiency of finely ground metallurgical slags, such as granulated blast-furnace slag with specific surface areas of 340 (1Sa) and 520 m²/kg (1Sb), air cooled blast-furnace slag (2S), demetallized steel slag (3S), calcareous ladle slag (4S), and copper slag (5S). The efficiency was tested on microbial representatives, such as: Gram-positive bacteria—Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus; Gram-negative bacteria—Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens; yeasts—Candida utilis, Rhodotorula glutinis; and microscopic filamentous fungi—Aspergillus niger, Penicillium funiculosum, Chaetomium globosum, Alternaria alternata, Trichoderma viride, Cladosporium herbarum. The efficiency was determined by dilution methods in agar growth media so that the resulting concentration of the tested slags was 10, 20, 40, and 60%. The antibacterial efficiency of the slags decreased in the order: S4 > S3 > S2 > S1a = S1b > S5, while their anti-yeast efficiency decreased in the order S4 > S1a = S1b = S3 > S2 > S5. Microscopic filamentous fungi were selectively sensitive to the slags; therefore, there is only an approximate order of efficiency of S4 > S3 = S1a = S1b > S5 > S2. Application of metallurgical slags into building materials and products provide them with increasing resistance against biodeterioration.

The article deals with studying the antifungal efficiency of carbide lime slurry compared to industrially manufactured commercial lime. Antifungal efficiency expressed as mould proofness properties was tested on the fungi using the procedure given in standard CSN 72 4310. A mixture of fungi Aspergillus niger, Chaetomium globosum, Penicillium funiculosum, Paecilomyces variotii and Gliocladium virens was utilized for testing. The scale for evaluating mould proofness properties according to CSN 72 4310 is from 0 to 5 in degree of fungi growth, where 0 means that no fungi growth occurs and the building products and materials possess fungistatic properties. The study confirms the fungistatic propeties of carbide lime slurry as well as industrially manufactured commercial lime. However, carbide lime slurry and industrially manufactured commercial lime possess no fungicidal effect.