Alkaline Activation of Hybrid Cements Binders Based on Industrial by-Products

Environmentally friendly building materials are becoming increasingly relevant in civil engineering in view of their contribution toward sustainable development. This research is focused on hybrid geopolymer concrete (geopolymer with ordinary Portland-cement (OPC) additive) with the objective of analysing strength development. In this research, hybrid geopolymer concrete, manufactured using biomass bottom ash, fly ash and production waste from the manufacture of aluminium fluoride (silica gel) with 4 different amounts of OPC (0%, 5%, 10% and 15%) is studied. Each blend is cured at a temperature of 50 0C and the material is tested after 7, 14 and 28 days. X-ray powder diffraction and energy-dispersive X-ray spectroscopy were used as investigation methods. The purpose of research was to study the chemical composition and the strength development in hybrid geopolymer concretemade from OPC and the industrial by-products mentioned above

PURIFIED WASTE FCC CATALYST AS A CEMENT REPLACEMENT MATERIAL

Zeolites are commonly used in the fluid catalytic cracking process. Zeolite polluted with oil products and became waste after some time used. The quantity of this waste inevitably rises by expanding rapidly oil industry. The composition of these catalysts depends on the manufacturer and on the process that is going to be used. The main factors retarding hydration process of cement systems and modifying them strength are organic compounds impurities in the waste FCC catalyst. The present paper shows the results of using purified waste FCC catalyst (pFCC) from Lithuania oil refinery, as Portland cement replacement material. For this purpose, the purification of waste FCC catalyst (FCC) samples was treated with hydrogen peroxide. Hydrogen peroxide (H2O2) is one of the most powerful oxidizers known. By acting of waste with H2O2 it can eliminate the aforementioned waste deficiency, and the obtained product becomes one of the most promising ingredients, in new advanced building materials. Hardened cement paste samples with FCC or pFCC were formed. It was observed that the pFCC blended cements developed higher strength, after 28 days, compared to the samples with FCC or reference samples. Typical content of Portland cement substituting does not exceed 30 % of mass of Portland cement in samples. Reducing the consumption of Portland cement with utilizing waste materials is preferred for reasons of environmental protection

Modified sawdust concrete/Modifikuotas pjuvenų betonas

Wood-cement materials are widely produced and applied in many developed countries. In this case special prepared wood aggregates are employed. Wood sawdust practically is not employed. Extracts, present in wood, slow down the cement hydration. The influence of mineral additives on this process was determined. The efficiency of mineral additives depends on their hydraulic activity. It has been found that the mineral components (additives) of sawdust concrete have a positive effect on cement setting and hardening due to two reasons: 1) hydraulic and other mineral additives absorb wood extracts from liquid phase which inhibit and retard setting of cement and reduce their concentration in solution; 2) reduce pH of liquid phase so the hemicellulose which is in sawdust or other wood aggregates, less disintegrate lightly soluable sugars. When sawdust amounts are different, the optimum cement and rottenstone relation is not constant: y = 1,29x −0,66 where y is cement and rottenstone mass relation, x is sawdust and binding material (cement+rottenstone) volume relation. The influence of sawdust concrete humidity on its strength was found: where y is concrete compressive strength (MPa), when its humidity X (%), R is concrete compressive strength (MPa), when its humidity W(%). The possibility of accelerating the hardening process of concrete mixes of cement-rottenstone (gaize)-sawdust system by means of steaming at 80 °C was studied, too. It is impossible when producing ordinary wood-cement materials. The physical and technical properties of sawdust concrete such as shrinkage strain, expansion deformations and elastic modulus were determined. Sawdust concrete contraction deformation depending on concrete density may vary by 8…14 mm/m and expansion (in humid conditions) by 1,1…2,5 mm/m. Deformation decreases when quartz sand additive is used. When the concrete gets dry repeatedly, deformations are smaller. The sawdust concrete elasticity modulus is similar to that of light concrete with inorganic additives having the same density. Its frost resistance depends on the concrete structure and cement quantity. When the concrete with a small amount of sawdust is used (cement+additive: sawdust=5:1), the samples endure 75 freezing cycles. The heat conductivity of sawdust concrete is low. The experimental data have shown that structural thermoinsulated small blocks can be produced from these concrete mixes. First Published Online: 26 Jul 201

Keramzito gamyba naudojant nesipučiantį molį, sapropelį ir glicerolį

&Scaron;io darbo tikslas - i&scaron;tirti keraminių plytų ir čerpių gamybai netinkančio, silpnai pučiančiosi (i&scaron;sipūtimo koeficientas <em>K_p</em>&nbsp;=&nbsp;2_&nbsp;-_&nbsp;2,5) ir nesipučiančio (<em>K_p</em>&nbsp;&lt;&nbsp;2) molio panaudojimo keramzito gamybai galimybes, molio pūtimuisi gerinti dedant &scaron;ių organinių priedų: biodyzelino gamybos atliekos - glicerolio, medienos drožlių plok&scaron;čių pjuvenų ir organinio sapropelio. Keramzito izoliacinės savybės gerėja didėjant i&scaron;degto molio &scaron;ukės akytumui. Kad molis pūstųsi geriau, į jį dažnai įmai&scaron;oma organinių priedų. Tirtas Krūnos telkinio III sluoksnio karbonatingasis molis be priedų netinka keramzito gamybai dėl per mažo i&scaron;sipūtimo koeficiento (<em>K_p</em>&nbsp;=&nbsp;1,25). Tam tikslui į i&scaron;džiovintą smulkiai maltą molį buvo įmai&scaron;oma įvairūs kiekiai (0&nbsp;%, 1&nbsp;%, 2&nbsp;%, 3&nbsp;%, 5&nbsp;%, 7&nbsp;% ir 10&nbsp;%) organinių atliekų. Granulės gamintos su vienu arba keliais pasirinktais degimo metu dujas i&scaron;skiriančiais priedais. Suformuotos ir i&scaron;džiovintos granulės degtos skirtingose temperatūrose iki jų apsilydimo temperatūros - nuo 1090_&nbsp;&deg;C iki 1170_&nbsp;&deg;C. Nustatytas i&scaron;degtų granulių pūtimasis ir vandens įmirkis. Tyrimų metu nustatyta, kad organinės atliekos yra efektyvus priedas, didinantis molio struktūros akytumą. Be to, molyje neturi būti daugiau kaip 5&nbsp;% sapropelio, rekomenduojamas glicerolio kiekis yra 1&nbsp;%_&nbsp;-_&nbsp;3&nbsp;%, optimalus pjuvenų kiekis - 3&nbsp;%. Bandinių, pagamintų su nurodytais priedų kiekiais ir i&scaron;degtų skirtingose temperatūrose, vandens įmirkis nevir&scaron;ija 15 %.<p><a href="http://dx.doi.org/10.5755/j01.ms.17.3.600">http://dx.doi.org/10.5755/j01.ms.17.3.600</a></p

The use of zeolitic waste in closed recirculating fish-farming systems

Kauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij

The Influence of Alumosilicate Gel Aging on the Synthesis of NaX Zeolite

Zeolites are among the least-known products for environmental pollution control, separation science and technology. The work studies synthesis of gel aging and duration of Na-X zeolite crystallization in studied conditions. To obtain the maximum crystallinity (40%) zeolite, gel aged for 24 h at room temperature and it lead to reduction of zeolite synthesis’ (95 °C) duration from 3 to 0.5 hours. The longer duration of aging time had been, the smaller zeolite crystals were obtained. An obtained IR spectrum showed that all samples of the absorption bands at the positions of maximum were as follows: 983-1012 cm-1, 717-756 cm-1, 564-590 cm-1 and 450-465 cm-1 were practically identical. This allowed ascribing tested samples to one type of zeolites Na-X. An obtained DSC curves for all samples were practically similar and have a wide endothermic peak with maximum 135 – 169 oC and a small exothermic peak about 853 – 956oC. Thermal analysis like IR spectra allowed ascribing the tested samples to one type of zeolites Na-X. The zeolite gel aging can be effectively used not only for shortening the duration of hydrothermal crystallization, but also for controlling size of zeolite crystal

Utilization of by-product waste silica in concrete - based materials

The usage of waste silica from AlF3 production is limited due to admixtures of fluoride in its composition. The negative effect of admixtures was eliminated by thermally activating this silica gel. After thermal activation the mineralogical composition of silica gel changes. Fluorine is binding in low-reactive compounds, which insignificant effect on the cement hydration process. The possibilities of using waste by-product silica in hardened cement paste were investigated. Silica gel could be used as additive of the hardened cement paste after thermal activation (1 hour at 800 °C temperature). It was discovered that the optimum content of thermally activated technogenic silica gel additive under the conditions explored was up to 10% of the total quantity of the cement. After 28 days of hardening, the strength of hardened cement paste increased 7 MPa when the quantity of the additive was - 10% of the total weight when compared to the strength qualities of the samples with no additives used

Sapropelis keramzito gamyboje

Tirtos organinio sapropelio panaudojimo galimybės keramzito gamyboje naudojant mažai besipučiančius ir nesipučiančius vietinius molius. Nustatyta, kad geriausiai nekarbonatingi molio su sapropelio priedu bandiniai pūtėsi esant 1070-1130 °C temperatūrai, o karbonatiniai - tik esant 1150 ± 10 "C temperatūrai. Geriausių pūtimosi savybių mišiniai gauti iš nekarbonatinio molio su 3-5 % organinio sapropelio. Jie pūtėsi esant 80 °C, kai Kpv = 3,36-3,42. Molio pūtimasis priklauso ne tik nuo sapropelio priedo kiekio, bet ir nuo molyje esančių karbonatų kiekio, kurie mažina pūtimąsi. Tirti moliai be degių priedų beveik nesiputė. Bandytas degus organinio sapropelio priedas pagerino molio pūtimosi savybes ir pažemino jo pūtimosi bei lydymosi temperatūrąIn the paper the possibility of the use of organic sapropel for expanded clay production, by using of low self expanding and non-self expanding local clays, is investigated. The sample with not carbonate clay and sapropel addition the best expands in 1070−1130oC temperature range, and that of carbonate clay – in a very narrow 1150 ± 10 temperature ranges. Mixtures of the best expanding properties contain not carbonate clay and 3−5% of organic sapropel. They expand in 80°C temperature range, at Kpv = 3.36−3.42. The clay expanding depends not only on the sapropel quantity, but also on the carbonate content, which reduces expansion. The investigated clays without flammable additives do not expand. The tested flammable organic sapropel addition improves clay expanding properties and downgrades the bloating and melting temperaturesVytauto Didžiojo universitetasŽemės ūkio akademij

Removal of ammonium ions by using zeolitic wastes

In this research the sorption capacity of ammonium ions was investigated by using zeolitic waste FCC catalyst. By using XRD analysis it was determined that maine mineral is zeolite Y which consist of this zeolitic waste. It was used as an adsorbent for petroleum refining during catalytic cracking, and after a certain time it contaminates and becomes a waste. This waste in Lithuania can make up to 200 tons per year. For ammonium removal two types of zeolitic materials were investigated. The first type was used untreated and the second one was activated by integrating in 15 % H2O2 aqueous solution. In our previous works it was determined that the zeolite sorption capability increased (about 1.75 times after 48h) after treatment with a hydrogen peroxide solution, but it wasn't investigated the amonium ion removal. The initial solution for ammonium ion removal were made by using NH4CI solution. Initials concentrations were lmg/1. The experiment werte carry out under dynamic conditions. Sorption durations were from 12 untill 72 hours. The iniatial results show that this type of zeolitics waste are suitable for amonium sorption from water solutionsKauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij