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.

The paper concerns selected environmental problems of crushing devices operation. The main scope was to determine the dust emission level of hammer, cone and jaw crusher, operating in plant conditions. There were registered dust emissions for these crushers along with determination their distributions. There were also introduced indices that enable us to estimate environmental burdensome of particular crusher, with taking into account technological conditions (comminution ratio, throughput). It appeared that the jaw crusher, despite the highest dust emission level, turned out to be of less environmental nuisance, considering its throughput and achieved comminution ratio.

The article regards the issues related to chalcedonite processing by means of particle size classification as well as densimetric separation. Chalcedonite is an unique rock and material with wide industrial applications in various industries. The investigative program included laboratory tests of chalcedonite classification in the classifier and the jig, as well as separation of the material in the dense liquid. The obtained results indicate that the products of particle size classification of chalcedonite in the classifier are characterized by a different chemical and mineralogical composition. The 0-0.3 mm particle size fraction contains over 96% of quartz, while the fine size fraction below 0.063 mm contain about 80% of quartz and 20% of clayish minerals. In the next stage of the investigative program, the densimetric separation of chalcedonite material in the jig and in dense liquid, was carried out. The results of the density classification in the jig indicate the different absorbability of the obtained chalcedonite density fractions. Fractions with a higher density were characterized by lower water absorption. The results of separation in the dense media liquid also showed that the obtained aggregate products are of significant differences in absorbability as well as high variability of the strength parameters. The results of the investigations show that the obtained products of the classification can be more efficiently utilized in industry, due to their diverse chemical and physical characteristics.

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Article concerns problem of jig beneficiation of mineral aggregates and focuses especially on problem of separation of hard-enrichable materials. Investigative programme covered tests in laboratory and semi-plant scale and material with different content of regular and irregular particles, along with various particle size fractions, was under analysis. Two patented solutions were utilized as methodological approach and densities and absorbabilities of individual products were determined and major novelty of approach consist in separate beneficiation of regular and irregular particles. Results of laboratory investigations showed that more favorable separation effectiveness was observed for the narrow particle size fractions of feed material. In terms of absorbability difference between separation products from I and IV layer was 0.4–0.5% higher for regular particles, and up to 0.5% higher for irregular grains. Differences in densities of respective products were 0.1% higher for regular particles. Results of semi-plant tests confirmed the outcomes achieved in laboratory scale. The qualitative characteristics of separation products in terms of micro-Deval and LA comminution resistance indices were one category higher for regular particles, and two categories higher for irregular grains, comparing to the raw material.