No abstract

Many byproducts and waste materials with pozzolanic properties can substitute natural raw materials in cement production. Some of these waste materials like fly ash and blast furnace slag are commonly harnessed by cement industry. Others are of seldom use due to limitations of the very centralized cement production systems currently in use. In the authors opinion, it is necessary to change this system to enable efficient utilization of various waste materials that are available locally (e.g., white and red ceramics). In this study, a new partially centralized system of cement production is proposed. The adoption of a new system would significantly reduce the volume of long-distance transportation and enable utilization of numerous locally available waste materials that are currently dismissed. The last stage of production of the ready-to-use cement would take place in situ. The cement would be produced on demand and be immediately used for concrete production on-site. The research program was conducted considering the importance of the quality of cements obtained in the new way, substituting up to 12% of its mass by white ceramics. The research program was proof of concept of the proposed cement production system. It was shown that the quality of “in situ cement” does not differ from standard cements.

This article presents the results of the research program aimed to analyze the opportunities for using waste ceramic pots for the production of watertight concrete. The mechanically processed crushed ceramic pots were added to the concrete mix in two ways: as a microfiller and as a recycled fine ceramic aggregate. The ceramic meal with a fraction below 0.25 mm was obtained by processing crushed pots using a mill and disintegrator. The pulverized ceramic material was added in 10%, 20%, and 30% of the cement mass. Recycled fine ceramic aggregate with a particle diameter up to 4 mm was created using only industrial mill. The aggregate obtained from pots was used to replace 20%, 30%, and 40% of the sand mass. Altogether, seven different mixes were created. The testing covered following properties: compressive strength, water absorption, and depth of water penetration. Concretes modified with the ceramic meal obtained higher compressive strength, lower water absorption and lower values of depth of water penetration in comparison to reference concrete. Mixes with recycled fine ceramic aggregate were characterized by slightly higher compressive strength in comparison to the reference concrete and similar values of water absorption and depth of water penetration.

The vast body of research conducted so far has focused on the use of waste glass as a partial replacement for cement or aggregate in the production of materials with cement matrix. This paper presents an alternative method of using glass waste for cement production. Grinding of previously burnt Portland clinker with glass cullet in green and white colours was used. The glass cullet was ground with Portland clinker in proportions of: 92.5% clinker and 7.5% green and white glass, 85% clinker and 15% green and white glass. Furthermore, pure cement was mixed with green and white glass fragmented in the disintegrator with the same proportions. This allowed for obtaining 8 series of cements (4 series with green glass and 4 series with white glass) and pure cement without waste glass. The compressive strength tests conducted after 2, 7 and 28 days made it possible to analyse the effect of the quantity and colour of waste glass and the method of its application (grinding with Portland clinker, mixing glass with pure cement) on the mechanical parameters of standard mortars. The highest mean compressive strength values after 2, 7 and 28 days were obtained for mortars made of cement coming from grinding of Portland clinker with 15% white glass. Furthermore, the following examinations were conducted: the beginning of the setting time and the degree of grinding of cements.

Our research focused on the influence of fillers obtained from crushed waste materials on the selected properties of concrete composites. The used waste materials were sourced from the production of ceramic tiles, ceramic pots, and sanitary ceramics. We evaluated concretes modified with the addition of 10% (by mass of cement) of different fillers. The properties, including the air content in the fresh concrete mix, consistency, compressive strength, and freeze-thaw resistance were examined. The evaluation of the freeze-thaw resistance was carried out by testing the concrete with the direct method for 150 cycles of freezing and thawing. The characteristics of the concrete porosity structure were assessed using automated digital image analysis. Concretes modified by coarse and fine fillers were characterized by different improvements in the mechanical properties and resistance to cycles of freezing and thawing. Composites with the addition of coarse fillers did not show any significant changes in comparison to the control concrete. An automated digital image analysis of the pore distribution in concrete proved to be an effective tool for the assessment of the freeze–thaw resistance of the concretes in question.