ANALIZA TRWAŁOŚCI STALOWYCH OBIEKTÓW MOSTOWYCH W ZALEŻNOŚCI OD ŚRODOWISKA KOROZYJNEGO

W artykule przedstawiono aktualne statystyki dotyczące sieci dróg województwa śląskiego zarządzanych przez Zarząd Dróg Wojewódzkich oraz ilości konstrukcji w zależności od typu ich ustroju nośnego. Poruszono aktualny w Polsce problem dotycząc trwałości stalowych obiektów mostowych z uwzględnieniem zjawiska korozji. Scharakteryzowano podstawowe czynniki wpływające na szybkość korozji niezbędne do oszacowania wpływu korozji na trwałość stalowych mostów drogowych m.in. czynniki atmosferyczne oraz czynniki wynikające z utrzymania obiektu. Zwrócono szczególną uwagę na kategorie korozyjności środowiska w którym wznoszone są konstrukcje stalowe, mające bardzo znaczący wpływ na postęp i szybkość procesu korozji. Omówiono procedurę badania wpływu korozji na trwałość stalowych konstrukcji mostowych opracowaną przez Instytut Badawczy Dróg i Mostów. Przedstawiono metodę obliczania czasu bezawaryjnego użytkowania konstrukcji. Szczegółowo scharakteryzowano, niezbędne do przeprowadzenia procedury obliczeniowej, redukcyjne współczynniki trwałości. Na podstawie własnej analizy określono czas bezawaryjnej pracy wybranych konstrukcji. Do obliczeń przyjęto cztery rzeczywiste mosty o dźwigarach stalowych, będących konstrukcją nośną dla żelbetowej płyty pomostowej. Wybrane mosty wzniesione zostały w różnych częściach kraju, charakteryzujących się odmienną agresywnością środowiska – środowisko nadmorskie, górskie, miejskie oraz neutralne. Obiekty różnią się rodzajem korozji występującym na ustrojach nośnych konstrukcji. Mosty różnią się również czasem powstania obiektów, co wpływa w znacznym stopniu na ich bezpieczne użytkowanie. Na zakończenie przeanalizowano wyniki otrzymane z przeprowadzonej analizy

Construction and demolition waste management in the European sustainable development strategy - status and perspective

Sektor budowlany generuje duże ilości odpadów, które powstają zarówno na etapie wznoszenia obiektów budowlanych, jak i podczas ich demontażu. W krajach Unii Europejskiej w 2018 roku wytworzono ponad 834 mln Mg odpadów budowlanych i rozbiórkowych, co stanowiło 36% wszystkich wytworzonych odpadów. Gospodarka tymi odpadami w poszczególnych krajach UE jest bardzo zróżnicowana, a średni poziom recyklingu tych odpadów mieści się w granicach 10-90%. W artykule scharakteryzowano najważniejsze europejskie akty prawne pozwalające na realizację strategii budownictwa zrównoważonego oraz zidentyfikowano przeszkody dla efektywnego procesu recyklingu. Ponadto przedstawiono analizę poziomu generowanych odpadów budowlanych i rozbiórkowych w krajach UE ze szczególnym uwzględnieniem odpadów wytwarzanych w Polsce.The construction sector generates large amounts of waste, which is generated both at the stage of bringing in construction objects and during their dismantling. In 2018, over 834 million Mg of construction and demolition waste was generated in the European Union countries, which accounted for 36% of all generated waste. The management of this waste in individual EU countries is very diversified, and the average level of recycling of this waste ranges from 10 to 90%. The article describes the most important European legal acts enabling the implementation of the sustainable building strategy and identifies obstacles to an effective recycling process. In addition, an analysis of the level of construction and demolition waste generated in EU countries was presented, with particular emphasis on waste generated in Poland

Implementation of lean instruments in ceramics industries

The article presents the results of the research on the level of implementation of Lean instruments in the ceramics industry. The research was carried out in ceramic factories in Poland and Germany. Based on the results obtained, the most commonly used Lean instruments in the ceramics industry were defined. The dependence of the use of Lean instruments on the size of the enterprise was also determined. It was established that the Lean activities undertaken in the ceramics industry are focused solely on the implementation of individual methods and tools, without a pre-defined goal. This approach in the ceramics industry is ineffective, but unfortunately it is most often used in the implementation of the Lean philosophy, especially in small ceramics enterprises

The influence of post-consumer car mats waste on selected concrete parameters

In recent years, a systematic increase of various types of wastes has been observed, including polymeric wastes that, to a large degree, are difficult to manage. The present paper deals with the problem of car mats wastes and the possibility of their application for producing concrete composites. The scope of the research involved designing and making concrete mixtures modified by waste rubber retrieved from rubber car mats. For the experiment the authors used: Portland cement CEM I 42,5R, sand, gravel aggregate of the 2-8 and 8-16 fractions, water, plasticizing and aerating admixture and car mats wastes fragmented into 0-2 mm and 2-8 mm. The authors made 4 series of concrete samples modified by wastes, for which the following factors have been assigned: compression strength after 7 and 28 days of maturing, absorptivity, frost resistance F100 of freezing and thawing and bulk density. In two samples’ composition (S1 and S2) the authors used 2-8 mm fraction rubber wastes as a substitute for 2-8 mm gravel in the amount of 5% and 7,5% of the cement bulk, making the density correction of 2-8 gravel. In contrast, in the remaining two samples S3 and S4 were modified by rubber wastes of the 0-8 mm fraction in the amount of 5% and 10%, respectively, of the cement bulk, subtracting a certain amount of the aggravate mixture at the same time. The research conducted for the series of the designed concrete samples, unfortunately did not confirm the thesis that rubber wastes retried from rubber car mats could be reused as the aggravate substitute

Flotation of zinc(II) and cadmium(II) ions from dilute aqueous solutions in the presences of inorganic ligands,

An experimental investigation is presented on competitive flotation of zinc(II) and cadmium(II) ions from dilute aqueous solutions with sodium dodecylbenzenesulfonate (DBSNa) as the anionic surfactant and hexadecylpyridinium chloride (CPCl) as the cationic surfactant. The effect of inorganic ligands, i.e. cyanides, thiocyanides, sulfates, thiosulfates, nitrates, and perchlorates on the selectivity of cadmium(II) over zin

Effect of fly and bottom ash mixture from combustion of biomass on strength of cement mortar

The preliminary results of fly and bottom ash mixture form combustion od biomass (80% of tree waste and 20% of palm kernel shells) for the produce of ceramic mortars has been presented. Currently, bio- ash from fluidized bed are deposited in landfills. Use of this ash to production of cement mortar instead of sand will reduce the consumption of the mineral resources. The chemical composition of this waste materials was determined using X-ray fluorescence (spectrometer ARL Advant ‘XP). Cement mortar were made using CEM I 42.5 R. The ash were added in an amount 20% of cement weight (in different proportions of fly and bottom ash). The results showed, that the compressive strength (after 28 days) of cement mortar containing ash is higher regardless of the type of ash mixture used. The highest compressive strength (increased by 7.0% compared to the control sample) was found for cement mortars in which the ratio of fly ash to bottom ash was 10/90. This mortars also showed the highest frost resistance (after 150 cycles freezes and unfreeze). The largest decrease the compressive strength (over 18.7%) after the frost resistance test. While cement mortars in which the ratio of fly ash to bottom ash was 90/10 showed the highest frost resistance (after 150 cycles freezes and unfreeze)

The effect of the addition of polypropylene fibres on improvement on concrete quality

Concrete serves as one of the most important construction materials, which thanks to its resistance and durability, gives total freedom in using it in building industry, and by extension in defining urban areas. Despite numerous advantages (ease of handling, high compressive strength, low production cost, heat resistance) it also has many disadvantages, including low tensile strength as well as sensitivity to destructive action of chemical agents. A constant growth in expectations concerning increasing the quality of concrete led to its polymer modification, whose aim was to eliminate above-mentioned disadvantages. The scope of the present research involved designing and making of concrete mixtures modified by 19, 30, 40 and 60 mm long polypropylene fibres. For the experiment the authors used: Portland cement CEM I 42.5R, sand, gravel aggregate of the 2-8 and 8-16 fractions, water, Master Pozzolith STD plasticizer and polypropylene fibres of various length. The authors made 4 series of concrete samples modified by fibres, for which the following factors have been assigned: compression strength after 7, 28 and 56 days of maturing as well as absorptivity, volumetric density and frost resistance after 100 cycles of freezing and thawing

High Efficiency of the Removal Process of Pb(II) and Cu(II) Ions with the Use of Fly Ash from Incineration of Sunflower and Wood Waste Using the CFBC Technology

In these research studies, fly ash (SW-FA) resulting from the incineration of sunflower (20%) and wood (80%) waste employing the circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Pb(II) and Cu(II) ions in adsorption processes. Currently, great emphasis is placed on circular economy, zero waste or climate neutrality strategies. The use of low-cost SW-FA waste seems to fit well with pro-ecological, economic and energy-saving trends. Hence, this material was characterized by various techniques, such as granulation analysis, bulk density, SEM-EDX, XRD and XRF analysis, BET, BJH, thermogravimetry, zeta potential, SEM morphology and FT-IR spectrometry. As a result of the conducted research, the factors influencing the effectiveness of the adsorption process, such as adsorbent dosage, initial and equilibrium pH, initial metal concentration and contact time, were analyzed. The maximum removal efficiency were achieved at the level of 99.8% for Pb(II) and 99.6% for Cu(II), respectively. The kinetics analysis and isotherms showed that the pseudo-second-order equation and the Freundlich isotherm models better describe these processes. The experiments proved that SW-FA can act as an appropriate adsorbent for highly effective removal of lead and copper from wastewater and improvement of water quality