Impact of mineral wool production waste on properties of sintered ceramics

Darbe sprendžiama problema – mineralinės vatos gamybos atliekų, kurios šiuo metu išvežamos į sąvartynus, panaudojimas keraminių gaminių gamyboje. Šiame darbe sukurta keraminė medžiaga, kurioje kaip liesinantis priedas panaudotos mineralinės vatos lydalo centrifugavimo (MVCF) atliekos. Tokio priedo panaudojimas leidžia taupyti gamtinius išteklius ir utilizuoti termoizoliacinių medžiagų gamyboje susidariusias atliekas bei pagerina keraminių gaminių savybes. Disertaciją sudaro įvadas, šeši skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Įvado pabaigoje pristatomos disertacijos tema autoriaus paskelbtos publikacijos ir pranešimai konferencijose bei disertacijos struktūra. Pirmasis skyrius skirtas literatūros apžvalgai. Skyriaus pabaigoje pateiktos išvados ir darbo uždaviniai. Antrajame skyriuje aprašytos darbe naudojamos žaliavos, jų savybės, tyrimų metodika, formavimo mišinių sudėtys bei jų parinkimas. Trečiajame skyriuje pateikti mineralinės vatos gamybos atliekų toksiškumo ir fenolio bei formaldehido nukenksminimo tyrimų rezultatai. Ketvirtajame skyriuje ištirtos išdegtų keraminių bandinių su liesinančiu technogeniniu priedu – MVCF atliekomis ir fliusuojančiu priedu – nefelino sienitu (NF) savybės. Penktajame skyriuje pateikti sukepusios keraminės šukės mikrostruktūros, mineralinės sudėties ir ilgalaikiškumo tyrimai. Šeštajame skyriuje pateikta keraminių gaminių gamybos technologija. Disertacijos tema paskelbti straipsniai: vienas – mokslo žurnale, referuojamame ir turinčiame citavimo indeksą Mokslinės informacijos instituto duomenų bazėje „Thomson ISI Web of Science“, vienas – mokslo žurnale, referuojamame Mokslinės informacijos instituto duomenų bazėje „Thomson ISI Web of Science“, vienas – konferencijų pranešimų medžiagoje, referuotoje Mokslinės informacijos instituto duomenų bazėje „Thomson ISI Proceedings“, vienas – mokslo žurnale, referuojamame tarptautinėje duomenų bazėje „Index Copernicus“, trys kituose leidiniuose. Disertacijos tema perskaityti 6 pranešimai Lietuvos konferencijose

Use of Magnesium Silicate Contaminated with Organic Compounds in Ceramic Materials as a Pore Modifier

This study investigated the use of organic compound waste (OCW) contaminated magnesium silicate/diatomite in ceramics. Substituting part of the clay (between 5 and 20 wt.%) with OCW modifies a pore structure and enhances the ceramic product’s thermal conductivity, density, and frost resistance. Prepared samples were tested at 1000–1060 °C temperatures and their structural parameters and Maage factor, useful for frost resistance prediction, were evaluated. Results show that OCW modifies the porous structure and improves the insulating properties of the ceramic body. Increasing OCW content up to 15% in the ceramic body decreases density by up to 15.0%, and thermal conductivity by up to 42.5%, because of the modified pore structure. According to structural parameters calculation, the higher frost resistance can be predicted for ceramic bodies containing 5–10% of OCW, according to Maage factor calculation ceramic bodies containing 5–20% of OCW are frost resistant. Designed ceramic products can be attractive for use in construction due to improved energy efficiency and reduced energy consumption in buildings due to their low thermal conductivity, satisfactory mechanical strength, and sustainability based on predicted frost resistance

Investigation into the properties of sintered ceramics from dysna clay and non-plastics additives

Recycling mineral wool spinning waste represents a rather serious problem. The results of the present research show that the suggested sintering ceramics out of low melting illite clay and mineral wool spinning waste is a promising way for solving the problem of mineral wool waste utilization. The conducted research into the properties of this compound has shown that by introducing 20% of waste into low melting clay allows producing ceramic materials possessing the following parameters: value of absorption is equal to 2,2%, density – 2169 kg/m3. The data of dilatometric investigation have demonstrated that adding 20% of MVCF component leads to reducing length from 2,8% to 1,4% at the temperature of 1070 ºC. Article in Lithuanian. Sukepusios keramikos iš dysnos radimvietės molio  ir liesinančių priedų savybių tyrimai Anotacija. Perdirbti mineralinės vatos centrifugavimo atliekas yra esminga problema. Darbe pateikti tyrimo rezultatai rodo, kad sukepusi keramika iš lengvai lydaus ilitinio molio ir mineralinės vatos centrifugavimo atliekų yra perspektyvus būdas mineralinės vatos atliekų naudojimo klausimui spręsti. Tiriamosios sistemos savybių tyrimai parodė, kad į lengvai lydųjį molį pridėjus 20 % šių atliekų, gauta sukepusi keramika. Nustatyta, kad išdegus bandinius esant 1040 ºC temperatūrai, tokios keramikos įmirkio vertė yra 2,02 %, tankis – 2169 kg/m3. Dilatometrinių tyrimų rezultatai parodė, kad į Dysnos radimvietės molį pridėjus liesinančio priedo – 20 % mineralinės vatos centrifugavimo atliekų, ilgio pokytis, esant 1070 ºC temperatūrai, sumažėjo nuo 2,8 % iki 1,4 %. Reikšminiai žodžiai: sukepusi keramika, mineralinės vatos centrifugavimo atliekos

The Effect of Natural and Synthesised Zeolites on Cement-Based Materials Hydration and Hardened State Properties

The synthesis of zeolites from difficult-to-utilise waste materials facilitates the creation of more financially attractive and efficient synthetic zeolites. These can be incorporated into construction materials, resulting in a reduction in cement usage and the production of superior, clean, and sustainable construction materials. The potential to enhance the hydration rate of fresh cement paste by substituting up to 10% of the cement with two synthetic zeolites—one commercially produced and the other synthesised from waste and natural zeolite—was explored. Due to a higher Al/Na ratio, newly sintered waste-based zeolite possesses six times higher electrical conductivity compared to industrially produced 4A zeolite and more than 20 times higher electrical conductivity compared to natural zeolite. As the sequence of this fact, substituting up to 10% of the cement with AX zeolite cement paste accelerates the maximum heat release rate time and increases the total heat by 8.5% after 48 h of hydration. The structure, compressive strength, and water absorption of the hardened cement paste depends on the Al/Na ratio, pH, and electrical conductivity values of the zeolite used. The findings revealed that AX zeolite, due to presence of mineral gibbsite, which speeds up hydration products, such as CSH development, increases the compressive strength up to 28.6% after 28 days of curing and reduces the water absorption by up to 1.5%. Newly synthesised waste-based AX zeolite is cheap because its production is based on waste materials and is mostly promising due to superior properties of created construction materials compared to the other presented zeolites

The Impact of the Amount of Water Used in Activation Solution and the Initial Temperature of Paste on the Rheological Behaviour and Structural Evolution of Metakaolin-Based Geopolymer Pastes

This study aimed to determine the impact of the initial temperature of the paste (from 5 °C to 35 °C) and the addition of water, which reflects a decrease in the molarity of activation solutions (AS) by diluting 10 M NaOH with distillate water, on the rheological properties of geopolymer pastes. Additionally, this resulted in changes to the physical–mechanical properties of geopolymers after curing. A higher amount of water in the AS composition and higher initial paste temperature led to an increase in the spread values up to 28% and decreases viscosity. A smaller amount of water in the AS composition and a higher initial paste temperature accelerated the speed of the geopolymer structure formation up to 1.5 times during the curing period, increased compressive strength and reduced apparent porosity and pore size. X-ray diffraction confirmed the compressive strength test results and revealed that the lower amount of water in the AS and the higher initial paste temperature for the geopolymer preparation significantly affected the mineral formation and physical and mechanical properties of the samples.This article belongs to the Special Issue Advanced Construction and Architecture 2020This research was funded by the European Regional Development Fund project, “A New Concept for Low-Energy Eco-Friendly House”, Grant Agreement No. 1.1.1.1/19/A/017

Effect of limestone particles on rheological properties and hardening process of plasticized cement pastes

The rheological properties (flow, fluidity, dynamic viscosity, stiffness rate) and hardening process (hydration, development of structure) of Portland - limestone cement (PLC) and Portland cement (PC) (strength class 42.5 R and N) pastes without and with superplasticizer (SP) based on synthetic polycarboxylatether (PCE) were investigated. It was found that limestone particles increase W/C and viscosity of cement pastes and reduction of water in plasticized pastes PCL is lower than in pastes PC. On the other hand, the fluidity of plasti cized cement pastes PCL is better and its thickening goes slower. The hydration and structure development in pastes PLC are going slower than in pastes PC. The impact of SP (when consistency of cement pastes is the same) on hydration process and hardening structure development of are going faster in plasticized cement pastes. The fineness of cements also has an influence on SP effect

Effects of Na₂CO₃/Na₂SiO₃ Ratio and Curing Temperature on the Structure Formation of Alkali-Activated High-Carbon Biomass Fly Ash Pastes

This study explored unprocessed high-carbon biomass fly ash (BFA) in alkali-activated materials (AAM) with less alkaline Na2CO3 as the activator. In this paper, the effects of the Na2CO3/Na2SiO3 (C/S) ratio and curing temperature (40 °C and 20 °C) on the setting time, structure formation, product synthesis, and physical-mechanical properties of alkali-activated BFA pastes were systematically investigated. Regardless of curing temperature, increasing the C/S ratio increased the density and compressive strength of the sample while a decrease in water absorption. The higher the curing temperature, the faster the structure evolution during the BFA-based alkaline activation synthesis process and the higher the sample’s compressive strength. According to XRD and TG/DTA analyses, the synthesis of gaylussite and C-S-H were observed in the sample with an increasing C/S ratio. The formation of the mentioned minerals contributes to the compressive strength growth of alkali-activated BFA pastes with higher C/S ratios. The findings of this study contribute to the applicability of difficult-to-recycle waste materials such as BFA and the development of sustainable BFA-based AAM

The Effect of Mechanical Activation of Fly Ash on Cement-Based Materials Hydration and Hardened State Properties

Fly ash from coal represents the foremost waste product of fossil fuel combustion. These waste materials are most widely utilised in the cement and concrete industries, but the extent of their use is insufficient. This study investigated the physical, mineralogical, and morphological characteristics of non-treated and mechanically activated fly ash. The possibility of enhancing the hydration rate of the fresh cement paste by replacing part of the cement with non-treated and mechanically activated fly ash, and the hardened cement paste’s structure and early compressive strength performance, were evaluated. At the first stage of the study, up to 20% mass of cement was replaced by untreated and mechanically activated fly ash to understand the impact of the mechanical activation on the hydration course; rheological properties, such as spread and setting time; hydration products; mechanical properties; and microstructure of fresh and hardened cement paste. The results show that a higher amount of untreated fly ash significantly prolongs the cement hydration process, decreases hydration temperature, deteriorates the structure and decreases compressive strength. Mechanical activation caused the breakdown of large porous aggregates in fly ash, enhancing the physical properties and reactivity of fly ash particles. Due to increased fineness and pozzolanic activity by up to 15%, mechanically activated fly ash shortens the time of maximum exothermic temperature and increases this temperature by up to 16%. Due to nanosized particles and higher pozzolanic activity, mechanically activated fly ash facilitates a denser structure, improves the contact zone between the cement matrix, and increases compressive strength up to 30%