scholarly journals GAS CONCRETE FOR CONSTRUCTION OBJECTS OF TRANSPORT INFRASTRUCTURE

2018 ◽  
Vol 15 (5) ◽  
pp. 774-786
Author(s):  
E. V. Fomina ◽  
V. S. Lesovik ◽  
I. V. Lashina
Keyword(s):  
Pore Structure ◽  
Raw Materials ◽  
Construction Material ◽  
Calculated Data ◽  
Sem Analysis ◽  
Transport Infrastructure ◽  
Sound Insulation ◽  
Vapor Permeability ◽  
Main Task ◽  
Bet Analysis

Introduction.Construction objects of transport infrastructure have different influence and service conditions. An actual technical task is the design of optimal microclimate for human operation in workshops and office buildings. Therefore, such conditions can be achieved by using of construction material with high parameters of heat- and sound-insulation such as a gas concrete. The main task of the research is the improvement of heat- and sound-insulation in the gas concrete.Materials and methods.The evaluation of the gas concrete efficiency is based on the research of such parameters as heat- and sound-insulation. The analysis of the material at macro- and micro-level is performed with SEM-analysis and BET-analysis. In addition, the complex of experimental and calculated data of physical and chemical characteristics for gas concrete is carried out.Results.As a result, the usage of amorphous alum inosilicate raw materials in gas concrete allows variation of parameters to effect on pore structure such as homogeneous pore distribution in bulk, thickness and density of interpore partition, pore shape and pore size. The reduction of aerated concrete density by 22.5 % leads to reducing of heat conductivity by 19.26 %. The formation of cellular structure with mainly closed pores allows reducing of sorption humidity and vapor permeability of material under different environmental humidity.Differently-sized pores in the gas concrete and predominantly small pores with size of 0.3-0.9 mm as well as with size up to 94,6 nm leads to increasing isolation index of airborne sound due to increasing of absorption of acoustic wave in frequency range of 125-4000 Hz. Complexly, it provides high sound-insolating parameters of wall envelopes.Discussion and conclusions.Monitoring of heat- and sound-insolation of the gas concrete due to optimization of pore structure allows formation of energy effective composites able to protect humans from unfavorable environment in the transport enterprises.

scholarly journals Study on microcrystalline cellulose/chitosan blend foam gel material

2020 ◽  
Vol 27 (1) ◽  
pp. 424-432
Author(s):  
Hongkai Zhao ◽  
Kehan Zhang ◽  
Shoupeng Rui ◽  
Peipei Zhao
Keyword(s):  
Microcrystalline Cellulose ◽  
Raw Materials ◽  
Pore Space ◽  
Sodium Dodecyl ◽  
Cost Effective ◽  
High Water ◽  
Aldehyde Group ◽  
Sem Analysis ◽  
Present Contribution ◽  
Bet Analysis

AbstractIn the present contribution, an environmental-friendly and cost-effective adsorbent was reported for soil treatment and desertification control. A novel foam gel material was synthesized here by the physical foaming in the absence of catalyst. By adopting modified microcrystalline cellulose and chitosan as raw materials and sodium dodecyl sulfonate (SDS) as foaming agent, a microcrystalline cellulose/chitosan blend foam gel was synthesized. It is expected to replace polymers derived from petroleum for agricultural applications. In addition, a systematical study was conducted on the adsorbability, water holding capacity and re-expansion performance of foam gel in deionized water and brine under different SDS concentrations (2%–5%) as well as adsorption time. To be specific, the adsorption capacity of foam gel was up to 105g/g in distilled water and 54g/g in brine, indicating a high water absorption performance. As revealed from the results of Fourier transform infrared spectroscopy (FTIR) analysis, both the amino group of chitosan and the aldehyde group modified by cellulose were involved. According to the results of Scanning electron microscope (SEM) analysis, the foam gel was found to exhibit an interconnected pore network with uniform pore space. As suggested by Bet analysis, the macroporous structure was formed in the sample, and the pore size ranged from 0 to 170nm. The mentioned findings demonstrated that the foam gel material of this study refers to a potential environmental absorbent to improve soil and desert environments. It can act as a powerful alternative to conventional petroleum derived polymers.

Technological Processes for Manufacturing Cellular Concrete Products for Construction

2018 ◽  
Vol 931 ◽  
pp. 634-639
Author(s):  
Ryben R. Kazaryan ◽  
Vitaly A. Khvan
Keyword(s):  
Construction Material ◽  
Sound Insulation ◽  
Vapor Permeability ◽  
High Rise ◽  
Interstitial Material ◽  
Coefficient Of Heat Conductivity ◽  
Artificial Stone ◽  
Moisture Conditions ◽  
To Receive ◽  
Cellular Concrete

Cellular concrete occupies one of the leading places in world practice of a high-rise construction as the constructional heat-insulating material used in case of construction and reconstruction of buildings and constructions of different purpose. In this artificial stone construction material pores (air cells with diameter 0.1-3.0mm) are distributed rather regularly and occupy from 20 to 90% of amount of concrete, providing high heatphysical qualities (coefficient of heat conductivity of 0.07-0.2 W/ms) that allows cellular concrete houses to keep heat well. Excessive (reserve) porosity of cellular concrete provides its frost resistance (compensates expansion of water when freezing and the formed ice without material destruction). Vapor permeability of cellular concrete provides fast removal of technological moisture from material and maintenance of normal moisture conditions in rooms, and rather high air permeability promotes preserving in rooms of fresh air. Significant growth in production the cellular concrete of products is caused by use of rather simple technologies allowing (due to change of degree of porosity and properties of interstitial material) to receive cellular concrete for thermal insulation or sound insulation, to make wall constructional heat-insulating products with a density 250-1200 kg/ m3 and strength of a 1-25 MPa.

Gluten-Free Dry Mixtures with Rice and Amaranth for Children over Three Years Old with Gluten Intolerance

Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov
Keyword(s):  
Celiac Disease ◽  
Treatment Effectiveness ◽  
Raw Materials ◽  
Calculated Data ◽  
Limited Range ◽  
Gluten Free ◽  
Fruit And Vegetable ◽  
Organoleptic Evaluation ◽  
Free Products ◽  
Wide Range

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.

scholarly journals Crushed Bricks: Demolition Waste as a Sustainable Raw Material for Geopolymers

2021 ◽  
Vol 13 (14) ◽  
pp. 7572
Author(s):  
Gigliola D’Angelo ◽  
Marina Fumo ◽  
Mercedes del Rio Merino ◽  
Ilaria Capasso ◽  
Assunta Campanile ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Building Materials ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Construction Material ◽  
Raw Material ◽  
The European Union ◽  
Total Energy Consumption ◽  
Demolition Waste ◽  
Crushed Brick

Demolition activity plays an important role in the total energy consumption of the construction industry in the European Union. The indiscriminate use of non-renewable raw materials, energy consumption, and unsustainable design has led to a redefinition of the criteria to ensure environmental protection. This article introduces an experimental plan that determines the viability of a new type of construction material, obtained from crushed brick waste, to be introduced into the construction market. The potential of crushed brick waste as a raw material in the production of building precast products, obtained by curing a geopolymeric blend at 60 °C for 3 days, has been exploited. Geopolymers represent an important alternative in reducing emissions and energy consumption, whilst, at the same time, achieving a considerable mechanical performance. The results obtained from this study show that the geopolymers produced from crushed brick were characterized by good properties in terms of open porosity, water absorption, mechanical strength, and surface resistance values when compared to building materials produced using traditional technologies.

scholarly journals Mineralogical and Microstructure Analysis for Characterization and Provenance of Ceramic Artifacts from Late Helladic Kastrouli Settlement, Delphi (Central Greece)

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Vayia Xanthopoulou ◽  
Ioannis Iliopoulos ◽  
Ioannis Liritzis
Keyword(s):  
Raw Materials ◽  
Analytical Techniques ◽  
Sem Analysis ◽  
Petrographic Analysis ◽  
Ceramic Assemblage ◽  
Thin Sections ◽  
Central Greece ◽  
High Calcium ◽  
Local Geology

The present study deals with the characterization of a ceramic assemblage from the Late Mycenaean (Late Helladic III) settlement of Kastrouli, at Desfina near Delphi, Central Greece using various analytical techniques. Kastrouli is located in a strategic position supervising the Mesokampos plateau and the entire peninsula and is related to other nearby coeval settlements. In total 40 ceramic sherds and 8 clay raw materials were analyzed through mineralogical, petrographic and microstructural techniques. Experimental briquettes (DS) made from clayey raw materials collected in the vicinity of Kastrouli, were fired under temperatures (900 and 1050 °C) in oxidizing conditions for comparison with the ancient ceramics. The petrographic analysis performed on thin sections prepared from the sherds has permitted the identification of six main fabric groups and a couple of loners. The aplastic inclusions recognized in all fabric groups but one confirmed the local provenance since they are related to the local geology. Fresh fractures of representative sherds were further examined under a scanning electron microscope (SEM/EDS) helping us to classify them into calcareous (CaO > 6%) and non-calcareous (CaO < 6%) samples (low and high calcium was noted in earlier pXRF data). Here, the ceramic sherds with broad calcium separation are explored on a one-to-one comparison on the basis of detailed mineralogical microstructure. Moreover, their microstructure was studied, aiming to estimate their vitrification stage. The mineralogy of all studied samples was determined by means of X-ray powder diffraction (XRPD), permitting us to test the validity of the firing temperatures revealed by the SEM analysis. The results obtained through the various analytical techniques employed are jointly assessed in order to reveal potters’ technological choices.

scholarly journals Alkali-Activated Zeolite 4A Granules—Characterization and Suitability Assessment for the Application of Adsorption

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 360
Author(s):  
Pauls P. Argalis ◽  
Laura Vitola ◽  
Diana Bajare ◽  
Kristine Vegere
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Morphological Properties ◽  
Solid Ratio ◽  
Suitability Assessment ◽  
Bet Analysis ◽  
Zeolite 4A ◽  
Compressive Strength Test ◽  
Alkali Activated

A major problem in the field of adsorbents is that binders (kaolin clay, bentonite) introduced to bind zeolites and ensure the needed mechanical strength, are not able to sorb gases like CO2 and N2, and decrease the overall adsorption capacity. To solve this problem, one of the pathways is to introduce a binder able to sorb such gases. Thus, in this study, the physical and mechanical properties of a novel binder based on metakaolin and its composite with zeolite 4A in the granular form were studied. Metakaolin was used as a precursor for alkali-activated binder, which was synthesized using an 8M NaOH activation solution. Raw materials were characterized using granulometry, X-ray diffraction (XRD), and differential thermal analysis (DTA); and final products were characterized using density measurements, a compressive strength test, XRD, Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM). Alkali-activated metakaolin was found to be efficient as a binding material when data for morphological properties were analyzed. A relationship was observed—by increasing the liquid-to-solid ratio (L/S), compressive strength decreased. Zeolite granule attrition was higher than expected: 2.42% and 4.55% for ZG-0.8, 3.64% and 5.76% for ZG-1.0, and 2.73% and 4.85% for ZG-1.2, measured at 4 and 5 atmospheres, respectively.

scholarly journals A 1D Model for Predicting Heat and Moisture Transfer through a Hemp-Concrete Wall Using the Finite-Element Method

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6903
Author(s):  
Maroua Benkhaled ◽  
Salah-Eddine Ouldboukhitine ◽  
Amer Bakkour ◽  
Sofiane Amziane
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Transfer ◽  
Construction Material ◽  
Climatic Conditions ◽  
Vapor Permeability ◽  
Transfer Model ◽  
The Finite Element Method ◽  
Concrete Wall ◽  
Element Method

Plant-based concrete is a construction material which, in addition to having a very low environmental impact, exhibits excellent hygrothermal comfort properties. It is a material which is, as yet, relatively unknown to engineers in the field. Therefore, an important step is to implement reliable mass-transfer simulation methods. This will make the material easy to model, and facilitate project design to deliver suitable climatic conditions. In recent decades, numerous studies have been carried out to develop models of the coupled transfers of heat, air and moisture in porous building envelopes. Most previous models are based on Luikov’s theory, considering mass accumulation, air and total pressure gradient. This theory considers the porous medium to be homogeneous, and therefore allows for hygrothermal transfer equations on the basis of the fundamental principles of thermodynamics. This study presents a methodology for solving the classical 1D (one-dimensional) HAM (heat, air, and moisture) hygrothermal transfer model with an implementation in MATLAB. The resolution uses a discretization of the problem according to the finite-element method. The detailed solution has been tested on a plant-based concrete. The energy and mass balances are expressed using measurable transfer quantities (temperature, water content, vapor pressure, etc.) and coefficients expressly related to the macroscopic properties of the plant-based concrete (thermal conductivity, specific heat, water vapor permeability, etc.), determined experimentally. To ensure this approach is effective, the methodology is validated on a test case. The results show that the methodology is robust in handling a rationalization of the model whose parameters are not ranked and not studied by their degree of importance.

scholarly journals Study of the structure and characteristics of autoclaved aerated concrete

2020 ◽  
pp. 23-32
Author(s):  
Veronika Aleksandrovna Alipova
Keyword(s):  
Building Material ◽  
Coefficient Of Thermal Expansion ◽  
Weight Ratio ◽  
Strength Properties ◽  
Sound Insulation ◽  
Vapor Permeability ◽  
Conventional Concrete ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete ◽  
Manufacturing Technologies

The lightweight and porous building material has many advantages over conventional concrete, such as a higher strength-to-weight ratio, a lower coefficient of thermal expansion and good sound insulation. This article focuses on the historical periodization of the development of autoclaved aerated concrete and a literature review that focuses on the influence of porosity, vapor permeability and strength properties of a given building material. The subject of this research is the analysis of the key historical events and manufacturing technologies that influenced the creation and transformation of the structural components of autoclaved aerated concrete. In the course of research, the author revealed that although aerated concrete is a&nbsp;new material in construction, it appeared a long time ago. Initially, five thousand years ago,&nbsp;this composition of the material was used as a plaster and&nbsp;brickwork mortar; showing a positive effect in construction, the aerated concrete over the years took the form of a cellular block, and its characteristics continue to be discovered. The properties, composition and structure of autoclaved aerated concrete are being improved through its composition and geometry of the shape of block,&nbsp;which contributed&nbsp;to environmental friendliness of the new building material, its durability,&nbsp;and creation of&nbsp;comfortable living conditions for people.&nbsp;However,&nbsp;the material requires&nbsp;new rational manufacturing technologies are needed in order to improve&nbsp;its quality and characteristics.

The Effect of Mineralizers on Synthesis of Perovskite-Phase Lanthanum Aluminate Powders

2011 ◽  
Vol 48-49 ◽  
pp. 1241-1244
Author(s):  
Xiu Hui Wang ◽  
Guo Quan Zhao ◽  
Yan Min Zhao ◽  
Hong Gao ◽  
Jin Long Yang
Keyword(s):  
Grain Growth ◽  
Raw Materials ◽  
Perovskite Phase ◽  
Good Control ◽  
Sem Analysis ◽  
Solid Reaction ◽  
Xrd Pattern ◽  
Lanthanum Aluminate

The solid-reaction was applied to synthesize perovskite-phase Lanthanum Aluminate powders by using AlOOH and La2(C2O4)3 as raw materials, mineralizer AlCl3 and AlF3 as the additives, graund and mixed, then calcined at 800°C and 1200°C for 3 h. The XRD pattern shows that mono-phase LaAlO3 powders can be obtained at 1200°C, and the SEM analysis indicates that the AlCl3 and AlF3 can promote the grain growth and have a good control of morphology.

SYNTHESIS AND CHARACTERIZATION OF NEEM-BASED ZINC OXIDE PHOTOCATALYST

2021 ◽  
Vol 36 (1) ◽  
pp. 9-15
Author(s):  
I.N Gana ◽  
V.U Ohageria ◽  
U.G Akpan ◽  
I.J Ani
Keyword(s):  
Zinc Oxide ◽  
Green Synthesis ◽  
Surface Area ◽  
Leaf Extract ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Sem Analysis ◽  
X Ray ◽  
Bet Analysis ◽  
Neem Leaf Extract

The use of chemicals for the synthesis of photocatalyts poses threat to the environment. In this study, an active photocatalyst, Dalbejiya Dongoyaro (Azadirachta indica)-based zinc oxide (ZnO) was biosynthesized from zinc acetate dihydrate using sol gel and precipitation methods. The synthesized samples were characterized using Fourier Transfer InfraRed (FTIR), X-Ray Diffractometry (XRD), Brunauer Emmet Teller (BET), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) characterization techniques. The XRD and SEM analysis of the green synthesized and non-green synthesized ZnO demonstrated the formation of hexagonal wurtzite crystalline structure and agglomerated morphology. EDX analysis demonstrated the existence of Zn and O as the major constituents of the as-synthesized nanoparticles with traces of carbon which could be attributed to the carbon tape of the sample holder. The BET analysis displayed that the surface area of the ZnO nanoparticles increased from 23.75 to 97.08 cm3/g after the green synthesis. Based on the surface area values, it can be derived that neem leaf extract enhanced the surface area of the green synthesized sample. Green synthesis is a promising route for the synthesis of photocatalyst nanoparticle which is environmentally friendly and sustainable method. Keywords: Zinc oxide, Neem leaf extract, Photocatalyt, Degradation, Bio-synthesis

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