The regulation of structural parameters of ceramics depending on the drying regime

Always in the shaped semimanufactures of ceramics is some humidity, which we must eliminate before burning. Drying process is to safeguard the satisfactory strength of semimanufactures. Additionally, changes of ceramic samples capacity is to end the drying process, associated with elimination of humidity that would not compose defects ‐ gaps, fractures, fragmentation etc. In this work it was shown, how the selected stages of drying regime influence the structural parameters of ceramics (reserve of porous volume, heterogeneity degree of structure, maximum rate of capillary rise according to watering front, capillary rate of mass flow, water absorption) and vice verse, how the selection of the dimensions of the stages for drying regime depends on the desired values of the of ceramics. Santrauka Džiovinimas gaminant keraminius dirbinius yra labai svarbus technologinis procesas, nes džiovinant turi baigtis keraminių bandinių tūrio pokyčiai, susiję su drėgmės pasišalinimu, kad neatsirastų defektų – plyšių, įtrūkių, nuskilimų ir t. t. Darbe buvo išnagrinėta, kaip džiovinimo režimo parinkimas gali lemti defektų atsiradimą ir tokias struktūrines keraminių bandinių charakteristikas, kaip poringosios erdvės rezervas, struktūros nevienalytiškumo laipsnis, maksimalus kapiliarinio pakilimo pagal drėkinimo frontą greitis, kapiliarinis masės srauto greitis ir vandens įmirkis. Tikslui pasiekti keraminiai bandiniai buvo paruošti parinkus 8 džiovinimo režimus, o kitus technologinius veiksnius (formavimo mišinio sudėtis, degimo temperarūra, temperatūros kėlimo greitis degant ir kt.) palikus nekintamus. Nustačius keraminės šukės struktūrines charakteristikas ir atlikus gautų duomenų statistinę analizę, buvo sudarytos empirinės lygtys. Pagal jas buvo pagrįsta, kaip kiekvienas parinktas džiovinimo režimo etapo dydis lemia struktūrinių rodiklių verčių kitimą ir kaip galima reguliuoti džiovinimo režimą, norint gauti tam tikras struktūrinių charakteristikų vertes. Reikšminiai žodžiai: keramika, struktūriniai rodikliai, džiovinimo režimas, statistinė analizė. First Published Online: 14 Oct 201

Possibilities to recycle auto glass waste in building ceramics

Substantial amounts of glass waste end up in landfills because unlike ordinary glass, auto glass is unsuitable for recycling in the glass industry due to organic additives. However, it was determined that the additives make auto glass waste appropriate for the production of building ceramics, which results in improved physical-mechanical and structural properties. The optimum quantity of the additive contained in auto glass waste amounts to 15% of the formation mixture, and the most appropriate burning temperature is 1080 °C. The density of such ceramic chip is 2059 kg/m3 , the water absorption determined after 72 h is 1.2%, and the forecasted frost resistance at the beginning of decomposition is 1343 cycles, but amounts to 2188 cycles at the end of decomposition

Peculiarities of destruction mechanism of polymeric intumescent fire protective coatings

The article describes the destruction mechanism of intumescent fire protective paint coatings at the time of their aging under the impact of simulated climatic factors. Steel plates covered in anti-corrosion varnishes and intumescent fire protective paint coatings of several types and different composition were used in the research, while certain samples were also additionally covered in protective coatings protecting from environmental effects. SEM, DTA and FT-IR researches were conducted on control samples and samples after aging. Aging was performed in 3 ways: according to regimes I and II in the laboratory and having stored them for 12 months under the outdoor conditions under the roof. The aging mechanism of materials was determined to be very similar when using different methods of aging: with increasing number of cycles, the extent of damage to the surfaces and their diversity increase. In all cases, chemical material changes were observed after artificial aging cycles compared to control samples. In aged samples, there were some new connections occurring, while others changed or disappeared judging from the number of waves and intensity of peaks, which shows that certain compounds form, while others change and disintegrate under the influence of environmental heat and mass exchange

The Possibilities of Paper Sludge Waste (PSw) Utilization in Cement Materials

The paper production is developed throughout the world, therefore, more paper sludge waste (PSw) is accumulating. The aim of this work was to determine the properties of PSw burned at 900 °C and its impact on physical–mechanical properties of cementitious matrix and evaluate its usage/utilization possibilities in cementitious materials. For the implementation of the aim, cement-based specimens were prepared and their –mechanical properties were determined. Specimens from five compositions were formed, with 2.5%, 5%, 7.5%, and 10% of the cement by weight replaced with PSw. When 5% of the cement was replaced with PSw, the compressive strength increased by approximately 7%, although density and ultrasound velocity slightly decreased (up to 1.5%). When 7.5% PSw was added, the compressive strength of the specimens decreased. To summarize, it can be stated that up to 5% PSw may be utilized/used for the preparation of cementitious mixtures. The usage of the waste allows environment conservation, reduced amount of cement in mixtures, and improvement of properties of cementitious materials.This article belongs to the Proceedings of Innovations-Sustainability-Modernity-Openness Conference (ISMO’19), Bialystok, Poland, 22–23 May 201

Influence of mullite wool waste on the properties of ceramics

In the paper, the influence of mullite wool waste additive on the properties of building ceramics is analysed. For that purpose four formation masses were prepared, dried and fired at the analogous regimes (maximum firing temperature 1080 degrees C). The fired samples were used to determine the structural and physical-mechanical properties. The values of these parameters are analysed: water absorption, total and effective porosity, rate of capillary mass flow, reserve of porous volume, compressive strength, density and estimated exploitation frost resistance. It has been determined that mullite wool waste can be applied to the production of building ceramics and the optimum quantity of waste in a formation mass is 10 % according to weight. Water absorption of those ceramic samples was less than 4 %, compressive strength was 28.6 MPa, density - 2033 kg/m(3), forecasted resistance to frost about 400 cycles

The dependence of the physical mechanical properties of expanded-clay lightweight concrete on the composition

Binder material is the most expensive raw component of concrete; thus, scientists are looking for cheaper substitute materials. This paper shows that when manufacturing, a part of the binder material of expanded-clay lightweight concrete can be replaced with active filler. The conducted studies show that technogenic – catalyst waste could act as similar filler. The study also includes the dependence of the physical and mechanical properties of expanded-clay lightweight concrete on the concrete mixture and the chemical composition of the samples obtained. Different formation and composition mixtures of expanded-clay lightweight concrete were chosen to determine the properties of physical-mechanical properties such as density, water absorption and compressive strength. Article in Lithuanian. Keramzitbetonio fizikinių-mechaninių savybių priklausomybė nuo sudėties Santrauka. Rišamosios medžiagos yra brangiausias betono žaliavos komponentas, todėl mokslininkai tokioms medžiagoms kaip cementas ir pan. ieško pigesnio pakaitalo. Šiame darbe parodyta, kad gaminant keramzitbetonį, dalį rišamosios medžiagos galima pakeisti aktyviaisiais mikroužpildais. Toks mikroužpildas, kaip parodė atlikti tyrimai, gali būti technogeninė atlieka – katalitinio krekingo reaktoriuje panaudotas katalizatorius. Publikacijoje taip pat pateiktos keramzitbetonio fizikinių-mechaninių savybių priklausomybės nuo betono mišinio ir cheminės gautų bandinių sudėties. Siekiant nustatyti savybių kitimo tendencijas, buvo parinktos skirtingos keramzitbetonio mišinių sudėtys ir nustatytos fizikinėsmechaninės savybės: tankis, vandens įmirkis ir gniuždymo stipris. Reikšminiai žodžiai: keramzitbetonis, katalizatorius, portlandcementis, keramzitas, fizikinės-mechaninės savybės

Impact of Electronic Waste Glass on the Properties of Cementitious Materials

The article analyses the impact of two different types of dispersive glass on cement hydration and compressive strength at 7 and 28 days. The study employed dispersive glass from various LCDs (TV sets, computer monitors, smart phones), characterised by a composition of approximately 8% SrO, and dispersive glass from washing machines, which consists mainly of SiO2, Na2O, and CaO. The chemical composition and particle-size distribution of different types of dispersive glass were analysed. The study compares the effect of electronic waste glass on cement hydration by evaluating the amount and rate of heat released during the process. In addition, the results of X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) are provided. Different types of glass were determined to have a similar effect on the physical and mechanical properties as well as the mineral composition of cementitious samples: density and UPV decrease up to 6% and compressive strength decreases by about 30%, when 5–20% of cement was replaced by glass waste. However, more prominent differences were observed in the workability of the mixtures: the waste glass from home appliances increased the spread by up to 25%, while the waste glass from electronic devices decreased the spread compared to the reference sample by approximately 20%. The mixtures modified with the waste glass of electronic devices had a higher degree of early hydration (96%) due to the higher water absorption of the mixtures compared to the waste glass of home appliances (88%)

Statybinės keramikos charakteristikų ir technologinių parametrų reguliavimo galimybės

Tiek pasaulio, tiek ir Lietuvos mokslininkų yra išnagrinėta, kaip kinta keramikos savybės, keičiant pusgaminių džiovinimo, degimo temperatūrą, naudojamus priedus ir jų kiekius formavimo mišinyje. Tačiau nėra pateikta keramikos savybių ir nagrinėjamųjų technologinių parametrų abipusio kompleksinio vertinimo, leidžiančio gauti greitą grįžtamąjį ryšį ir reguliuoti vykdomą technologinį procesą. Knyga skirta keraminės produkcijos gamintojams, mokslininkams ir studentams, studijuojantiems statybinių medžiagų savybes ir gamybos technologijas

The dependence of the value of ceramics resistance to frost on the composition of raw material mixture / Keramikos atsparumo šalčiui priklausomybė nuo formavimo mišinio sudėties

The operational resistance of ceramic products to frost is a persistent problem. In order such products should remain of high quality without losing their initial qualities for a long time, it is necessary to improve the technological process of production. This work is confined to selecting the composition of the formation mix in order to turn attention to the amount of every component of the formation mix that can positively or negatively influence the operational resistance of ceramics to frost. The paper presents 8 formed batches of ceramic samples different in composition while being dried and burned under similar conditions. Operational resistance to frost was determined according to the established standard. The performed analysis of the obtained experimental data allowed working out an empirical equation forecasting operational resistance to frost according to the composition of the formation mix. Santrauka Keraminių gaminių eksploatacinis atsparumas šalčiui yra svarbi šių dienų problema. Kad keraminiai mūro gaminiai ilgai išliktų kokybiški, nepraradę savo pradinių savybių, reikia tobulinti technologinį jų gamybos procesą. Šiame darbe buvo nustatyta, kaip kiekvienas formavimo mišinio komponento kiekis gali lemti keraminių bandinių eksploatacinį atsparumą šalčiui. Atliekant darbą, buvo suformuotos aštuonios keraminių bandinių partijos. Jos buvo sudarytos iš tokių formavimo mišinio komponentų, kaip molis, smėlis, maltas stiklas, skaldelė, durpės ir antracitas. Bandiniai buvo džiovinami ir degami vienodomis sąlygomis (didžiausia degimo temperatūra—1080°C). Eksploatacinis atsparumas šalčiui buvo nustatytas pagal tuo metu galiojusio LST 1272–92 standarto 3.5.3 p. Atlikus regresinę gautų eksperimentinių duomenų analizę, buvo sudaryta empirinė lygtis, kuria remiantis galima prognozuoti eksploatacinį atsparumą šalčiui pagal formavimo mišinio sudėtį. Reikšminiai žodžiai: keramika, atsparumas šalčiui, formavimo mišinio sudėtis, savybės, statistinė analiz

Frost resistant porous ceramics

Extremely actual problem of these days is the production of ceramics which is resistant to frost under exploitation and jointly effective (porous), because these ceramic wall articles will be particularly suitable for building the facades which are being exploited under aggressive conditions (e.g. a seaside zone). Such a brick building will have a low coefficient of thermal conductivity and will be resistant to frost (the surface of the bricks will not decay). The porous and at the same time frost resistant (under exploitative conditions) ceramic material was obtained, when composition of formation mix was as follows: (59.2 – 72.8) % of clay, (7.2 – 10.8) % of sand, (3.2 – 4.8) % of crushed bricks, (10.4 – 15.6) % of sawdust and (6.4 – 9.6) % of milled glass. When ceramic samples were formed and burned under regime (maximum burning temperature is to 1100 °C), ceramics which exploitation frost resistance is more than 300 cycles, total open porosity is 40 %, and the predicted coefficient of thermal conductivity is (0.37 – 0.42) W/mK