Ing. Aleš Palička

Ing. Aleš Palička

Tento článek se zabývá vlivem mletého odpadního skla jako částečné náhrady cementu (10-50 %) na mechanické vlastnosti cementových past. Výsledky ukázaly, že vyšší obsah skla vede k počátečnímu snížení pevnosti, ale dlouhodobému zlepšení pevnosti v důsledku pucolánové reakce. Pevnost v ohybu byla ovlivněna mikrotrhlinami v důsledku absence kameniva. Nízké hladiny náhrady skla (do 20 %) jsou vhodné, zatímco vyšší hladiny (> 30 %) výrazně snižují pevnost. Další výzkum by se měl zaměřit na chemickou aktivaci skla.

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Ing. Aleš Palička

The article focusses on the effects of waste Si-based material on the mechanical properties of the resulting cement pastes. In this study we use Portland cement CEM I 42.5R and Si-based waste materials from the packaging industry from Recifa, a.s. The difference between individual samples was in the concentration of Si-based materials. We investigate the influence of five different amounts of SiO2-based materials, namely, 10 wt. %, 20 wt. %, 30 wt. %, 40 wt. % and 50 wt. %. The determined mechanical properties were compressive and flexural strengths. Mechanical properties were investigated in 7 and 28 day samples with dimensions equal to 40 × 40 × 160 mm. The results showed a negative effect of Si-based materials on mechanical properties.

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Ing. Aleš Palička

The article focuses on the investigation of the environmental impact of contaminated by colloidal aggressive substances on a 50-year-old wastewater treatment plant, where the sampling of core boreholes of DN150mm × 370 mm in the tank was made. The properties investigated were the microstructure and compressive strength of the concrete. The results showed that the aggressive environment had no effect on the resulting compressive strength of the concrete.

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Ing. Aleš Palička

This research work deals with the issue of laboratory testing of commonly available recycled fine aggregates, namely concrete recyclate, mixed recyclate and brick recyclate. Their geometrical properties: granulometric composition and fine particle content, including physical properties: bulk density and water absorption are investigated. The tests themselves are carried out according to available standards, which are currently mainly standards for testing natural aggregates, and it is necessary to assess the suitability of these tests for recycled aggregates as well. The results found for concrete recyclates confirm the use of these standards to obtain the properties mentioned, but the bulk density and absorption tests are inconclusive in the case of mixed and brick recyclates. Subsequently, test concrete specimens were produced in which natural fine aggregate and concrete recyclate were substituted at 33, 66 and 100 %. A series of tests were performed on the hardened concrete: bulk density, absorption, porosity and compressive strength. From the results obtained, the use of concrete recyclate in concretes with the replacement of natural fine aggregate at 33% is suitable, without a significant reduction in the observed properties.

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Ing. Aleš Palička

The study delves into the impact of waste silicon-based materials on the mechanical characteristics of the resulting cement pastes. The investigation uses Portland cement CEM I 42.5R in conjunction with silicon-based waste materials sourced from the packaging industry, specifically from Recifa, a.s. Variations between the sample groups arise from differences in the concentration of silicon-based materials and the method of surface treatment. The inquiry seeks to assess the effects of two distinct levels of Si-based material incorporation, namely 10 wt. % and 20 wt. %, along with plasma treatment involving two different gases: oxygen (O2) and hydrogen (H2). The mechanical attributes under scrutiny encompass compressive and flexural strengths. The evaluation of mechanical properties is carried out on samples aged 28 days, with dimensions measuring 20 × 20 × 100 mm.

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