Clinoptilolite is a precious zeolite mineral that has the most comprehensive physicochemical properties among all the zeolite group minerals. Due to these unique properties, clinoptilolite has a wide range of applications in many different industries. In Poland, the clinoptilolite occurs only as an accompanying mineral in the sedimentary rocks nearby Rzeszów. In Europe, the abundant clinoptilolite-bearing deposits are located in Slovakia and Ukraine, where clinoptilolite mineralization occurs in the volcanic tuffs. Due to clinoptilolite’s rare performance, it is extremely crucial to manage its deposits in a complementary manner. In this paper, the mineralogical and structural characterization of the clinoptilolite powders obtained by mineral processing of the clinoptilolite-rich tuffs from Slovakia and Ukraine deposits were discussed. The scope of research covered determination of the mineral composition of the tuffs, structural analysis of the clinoptilolite crystals, as well as textural and physical properties of the powders obtained by mineral processing of the tuffs. In addition, this paper includes the comparative study of the most significant zeolite deposits in the world and investigated clinoptilolite-rich tuffs. A wide spectrum of methods was used: X-ray powder diffraction (XRD), thermal analysis (DSC, TG), X-ray fluorescence (XRF), optical microscopy, Scanning Electron Microscopy (SEM-EDS), the laser diffraction technique, and low-temperature nitrogen adsorption/desorption. The test results indicated that the major component of the tuffs is clinoptilolite, which crystallized in the form of very fine-crystalline thin plates. The clinoptilolite mineralization in the Ukrainian and Slovakian tuffs exhibited a strong resemblance to the clinoptilolite crystals in Yemeni and Turkish tuffs. With respect to the mineral composition, the investigated tuffs showed excellent conformity with the Miocene white tuffs from Romania. The Ukrainian and Slovakian tuffs do not reveal the presence of the clay minerals, which is quite common for naturally occurring zeolite-rich rocks in various deposits in the world. The textural features together with mineral composition of the investigated samples incline that they are potentially suitable raw materials for the sorbent of petroleum compounds. Moreover, the obtained results can be useful indicators with respect to the crushing and compaction susceptibility of the Ukrainian and Slovakian clinoptilolite-rich tuffs.

The article shows investigations on the behavior of preplaced aggregate concrete with regular and irregular coarse aggregates. The thermal properties, compressive strength, and internal structure were analyzed based on computed tomography images. The regular and irregular shapes of aggregates were obtained according to patented technology, which is possible to produce in both laboratory and industrial conditions. Based on the conducted calculations, heat storage capacity was assessed. The influence of grain shape on the material strength, porosity, and hydration gaps was determined. Debonded porosity, as a result of aggregate impurities, was shown using computer tomography analysis. It was shown that the arrangement and shape of the grains has a significant impact on the performance properties of hardened preplaced concrete.

In this study, nanofibers of poly (acrylic acid) (PAAc), polyacrylamide (PAAm) and poly (vinyl alcohol) (PVOH) were prepared using the electrospinning technique. Based on the Taguchi DOE (design of experiment) method, the effects of electrospinning parameters, i.e., needle tip to collector distance, polymer solution concentration, applied voltage, polymer solution feed rate and polymer type, on the diameter and morphology of polymer nanofibers were evaluated. Analyses of the experiments for the diameters of the polymer nanofibers showed that the type of polymer was the most significant factor. The optimal combination to obtain the smallest diameters with minimum deviations for electrospun polymer nanofibers was also determined. For this purpose, the appropriate factor levels were determined as follows: polymer PAAm, applied voltage 10 kV, delivery rate 0.1 mL/h, needle tip to collector distance 10 cm, and polymer solution concentration 8%, to obtain the thinnest nanofibers. This combination was further validated by conducting a confirmation experiment, and the average diameter of the polymer nanofibers was found to be close to the optimal conditions estimated by the Taguchi DOE method.

Lightweight aggregates are a material used in many industries. A huge amount of this material is used in construction and architecture. For the most part, lightweight construction aggregates are obtained from natural resources such as clay raw materials that have the ability to swell at high temperatures. Resources of these clays are limited and not available everywhere. Therefore, opportunities are being sought to produce lightweight artificial aggregates that have interesting performance characteristics due to their properties. For example, special preparation techniques can reduce or increase the water absorption of such an aggregate depending on the needs and application. The production of artificial lightweight aggregate using various types of waste materials is environmentally friendly as it reduces the depletion of natural resources. Therefore, this article proposes a method of obtaining artificial lightweight aggregate consolidated using two methods: drum and dynamic granulation. Hardening was achieved using combined methods: sintering and hydration, trying to maintain the highest possible porosity. Waste materials were used, such as dust from construction rubble and residues from the processing of PET bottles, as well as clay from the Bełchatów mine as a raw material accompanying the lignite overburden. High open porosity of the aggregates was achieved, above 30%, low apparent density of 1.23 g/cm³, low leachability of approximately 250 µS. The produced lightweight aggregates could ultimately be used in green roofs.

The purpose of this article is to determine the effect of granite powder grain size and grinding time on the properties of cement paste. A series of cement pastes modified by the addition of granite powder were made and the properties of the fresh mixtures and the mechanical properties of hardened pastes were studied. Based on the study, the best results, from the point of view of the application of granite powder in cementitious composites, were obtained for a sample with granite powder ground for 3 h, in which 50% of the particles were smaller than 4 μm, and 90% were below 20 μm. Compressive strength of 55 MPa and flexural strength of 6.8 MPa were obtained on this sample after aging for 28 days. To confirm the validity of using granite powder as substitute materials, additional tests such as scanning microscopy with elemental analysis (SEM, EDS) and infrared (FTIR) studies were performed.