scholarly journals PERFORMANCES OF HIGH POROUS CELLULAR CONCRETE

2020 ◽  
Vol 3 (5) ◽  
pp. 5-14
Author(s):  
R. Fedyuk ◽  
A. Baranov ◽  
Yu. Ilinsky ◽  
Afonso Rangel Garcez de Azevedo
Keyword(s):  
Waste Heat ◽  
Point Of View ◽  
Sound Insulation ◽  
Water Repellent ◽  
Foam Concrete ◽  
Rigid Frame ◽  
Mechanical Adhesion ◽  
Airborne Noise ◽  
Aerated Concrete ◽  
Cellular Concrete

The widespread use of cellular concrete for enclosing structures forces researchers to develop ways to im-prove their performance and durability. Compositions of aerated and foam concrete with the use of waste heat power engineering have been developed. The optimal formulation ratios have been identified that con-tribute to the creation of a rigid interpore matrix and water-repellent pore protection. The regularities of the synthesis of aerated concrete and foam concrete were established, which consist in optimizing the processes of structure formation through the use of a polymineral cement-ash binder and a pore-forming agent. The mix composition intensifies the process of hydration of the system, which leads to the synthesis of a poly-mineral highly porous heterodispersed matrix. The increased activity and granulometry of aluminosilicates predetermine an increase in the number of contacts and mechanical adhesion between particles during com-paction, strengthening the framework of the interpore partitions. The mechanism of the influence of the composition of the concrete mix on the microstructure of the composite is established. The calculated sound insulation of airborne noise shows sufficient characteristics for using aerated concrete blocks as enclosing structures. One of the main advantages of aerated concrete is its low thermal conductivity, which is especial-ly important from the point of view of ensuring the energy efficiency of buildings and structures. Even in spite of the high values of open porosity of the developed aerated concrete, the rigid frame makes it possible to achieve almost 2 times higher frost resistance characteristics than that of the reference specimen

scholarly journals EFFECT OF POROUS STRUCTURE ON SOUND ABSORPTION OF CELLULAR CONCRETE

2020 ◽  
Vol 3 (2) ◽  
pp. 5-18 ◽  
Author(s):  
R.S. Fedyuk ◽  
A. Baranov ◽  
Y.H. Mugahed Amran
Keyword(s):  
Open Porosity ◽  
Sound Absorption ◽  
Concrete Mixture ◽  
Sound Waves ◽  
Foam Concrete ◽  
Mechanical Adhesion ◽  
The Matrix ◽  
Reduce Shear Stress ◽  
The Mathematical Model ◽  
Cellular Concrete

the compositions of gas and foam concrete with improved acoustic characteristics were developed. The optimal form of porosity, which contributes to the absorption of sound waves, both in the range of audible frequencies and at infrasonic and ultrasonic frequencies, is revealed. The mathematical model for designing sound-absorbing concrete was improved, taking into account both the porosity of the composite and the influence of the porous aggregate. The laws of synthesis of aerated concrete and foam concrete are established, which consist in optimizing the processes of structure formation due to the use of a polymineral cement-ash binder and blowing agent. The composition of the composite intensifies the process of hydration of the system, which leads to the synthesis of a polymineral heterodisperse matrix with an open porosity of more than 60%. Peculiarities of the influence of the “Portland cement – aluminosilicate – complex of modifiers” system on the rheology of the concrete mixture was identified, which can significantly reduce shear stress and create easily formed cellular concrete mixtures. The increased activity and granulometry of aluminosilicates predetermine an increase in the number of contacts and mechanical adhesion between particles during compaction, strengthening the frame of inter-pore septa. The mechanism of the influence of the composition of the concrete mixture on the microstructure of the composite is established. The presence of refined aluminosilicates and a complex of additives in the system along with cement contribute to the synthesis of the matrix with open porosity, thereby increasing the sound absorption coefficient.

scholarly journals New Method for Diagnostic of Heat Engineering and Mechanical Properties of Cellular Concrete

2019 ◽  
Vol 9 (1) ◽  
pp. 6885-6887
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Information Technology ◽  
Optical Method ◽  
New Method ◽  
Modern Approach ◽  
Heat Engineering ◽  
Aerated Concrete ◽  
Pore Arrangement ◽  
Cellular Concrete

The article presents the results of studies assessing the structure of cellular concrete using a photo-optical method based on the use of a modern approach from the standpoint of information technology. Based on the photo-optical method, a reverse formulation of the problem is also possible: on the basis of a given percentage of porosity of the material, obtain the most optimal pore arrangement (type of packaging) that meets the specified strength and thermal conductivity of aerated concrete. Having a specific type of image of aerated concrete obtained as a result of modeling, otherwise, a specific type of packing of pores of certain sizes that meets the required (specified) characteristics, then, we can set the technological task of obtaining it.

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 new material in construction, it appeared a long time ago. Initially, five thousand years ago, this composition of the material was used as a plaster and 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, which contributed to environmental friendliness of the new building material, its durability, and creation of comfortable living conditions for people. However, the material requires new rational manufacturing technologies are needed in order to improve its quality and characteristics.

scholarly journals Preparation and Physical Properties of High-Belite Sulphoaluminate Cement-Based Foam Concrete Using an Orthogonal Test

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 984 ◽  
Author(s):  
Chao Liu ◽  
Jianlin Luo ◽  
Qiuyi Li ◽  
Song Gao ◽  
Zuquan Jin ◽  
...  
Keyword(s):  
Physical Properties ◽  
Economic Cost ◽  
Pore Wall ◽  
Water Repellent ◽  
Dry Density ◽  
Foam Concrete ◽  
Range Analysis ◽  
Foaming Agent ◽  
Sulphoaluminate Cement ◽  
Foam Properties

Prefabricated building development increasingly requires foam concrete (FC) insulation panels with low dry density (ρd), low thermal conductivity coefficient (kc), and a certain compressive strength (fcu). Here, the foam properties of a composite foaming agent with different dilution ratios were studied first, high-belite sulphoaluminate cement (HBSC)-based FCs (HBFCs) with 16 groups of orthogonal mix proportions were subsequently fabricated by a pre-foaming method, and physical properties (ρd, fcu, and kc) of the cured HBFC were characterized in tandem with microstructures. The optimum mix ratios for ρd, fcu, and kc properties were obtained by the range analysis and variance analysis, and the final optimization verification and economic cost of HBFC was also carried out. Orthogonal results show that foam produced by the foaming agent at a dilution ratio of 1:30 can meet the requirements of foam properties for HBFC, with the 1 h bleeding volume, 1 h settling distance, foamability, and foam density being 65.1 ± 3.5 mL, 8.0 ± 0.4 mm, 27.9 ± 0.9 times, and 45.0 ± 1.4 kg/m3, respectively. The increase of fly ash (FA) and foam dosage can effectively reduce the kc of the cured HBFC, but also leads to the decrease of fcu due to the increase in mean pore size and the connected pore amount, and the decline of pore uniformity and pore wall strength. When the dosage of FA, water, foam, and the naphthalene-based superplasticizer of the binder is 20 wt%, 0.50, 16.5 wt%, and 0.6 wt%, the cured HBFC with ρd of 293.5 ± 4.9 kg/m3, fcu of 0.58 ± 0.02 MPa and kc of 0.09234 ± 0.00142 W/m·k is achieved. In addition, the cost of HBFC is only 39.5 $/m3, which is 5.2 $ lower than that of ordinary Portland cement (OPC)-based FC. If the surface of the optimized HBFC is further treated with water repellent, it will completely meet the requirements for a prefabricated ultra-light insulation panel.

Thermal Insulating and Constructive Foamed Concrete on a Composite Gypsum Binder

2019 ◽  
Vol 974 ◽  
pp. 125-130 ◽  
Author(s):  
Natalia V. Chernyisheva ◽  
Svetlana V. Shatalova ◽  
Maria Yu. Drebezgova ◽  
Evgeniy N. Lesnichenko
Keyword(s):  
Concrete Mixture ◽  
Foam Concrete ◽  
Thermal Insulating ◽  
Mineral Addition ◽  
Foamed Concrete ◽  
Stepwise Loading ◽  
Cellular Concrete ◽  
Loading Scheme

The article discusses the possibility of obtaining the effective thermal insulating and constructive foamed concrete on a composite gypsum binder. The composition was selected, the stepwise loading scheme of the foam concrete mixture components was proposed, the properties and microstructure of cellular concrete based on a composite gypsum binder with mineral addition of finely-dispersed concrete scrap were studied.

Composite Binder for Structural Cellular Concrete

2019 ◽  
Vol 945 ◽  
pp. 53-58 ◽  
Author(s):  
M.Y. Elistratkin ◽  
E.S. Glagolev ◽  
M.V. Absimetov ◽  
V.V. Voronov
Keyword(s):  
Building Materials ◽  
Negative Impact ◽  
Average Density ◽  
Construction Costs ◽  
Competitive Situation ◽  
Composite Binder ◽  
Mineral Supplements ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete ◽  
Cellular Concrete

Non-autoclaved aerated concrete is the only viable alternative to gas silicate when organizing its manufacture on the basis of regional small and medium capacity production. This aims to improvement the competitive situation on the building materials market and optimizing the construction costs. The possibility of expanding the application field of this material due to the increase in strength characteristics while maintaining an unchanged average density is of special interest. The guarantee of proposed solutions economic and technical efficiency is the transition from traditional portland cement to composite binders based on it. The article discusses the quantity and composition of the mineral supplements feasibility to optimize the binder properties of the problem peculiarities to reduce consumption of cement and chemical modifiers that increase the rate of curing and totals of non-autoclaved aerated concrete investigated compatibility issues between components to eliminate their negative impact on the formation of porous structure of the final product.

Study on Properties of Foam Concrete Based on Fractal Theory

2011 ◽  
Vol 194-196 ◽  
pp. 1916-1919 ◽  
Author(s):  
Wen Ling Tian ◽  
Jiang Bo Yang ◽  
Xiao Yan Zhao
Keyword(s):  
Fractal Dimension ◽  
Fly Ash ◽  
Thermal Insulation ◽  
Fractal Theory ◽  
High Strength ◽  
Sound Insulation ◽  
Foam Concrete ◽  
Insulation Property ◽  
Foaming Agent ◽  
Thermal Insulation Property

Foam concrete is provided with light weight, thermal insulation, sound insulation and fire resistance, good seismic performance and other characteristics. To improve properties of foam concrete microstructure is studied with the help of fractal theory, fractal dimension related to mechanical properties and thermal performance of foam concrete is calculated by MATLAB language program. The results indicate that the microstructure of foam concrete showed significant fractal character, the fractal dimension is between 1.3 and 2.0. Apparent density, 28d compressive strength, and thermal conductivity decreases with the increase of fly ash and foaming agent content, fractal dimension increased. Formulas of fractal dimension and the fly ash, foaming agent content were established. Foam concrete with low density, high strength, and good thermal insulation property will be prepared conducted by the formulas.

The Use of Anthracite Fly Ash for the Production of Autoclaved Aerated Concrete

2012 ◽  
Vol 512-515 ◽  
pp. 3003-3006
Author(s):  
Rostislav Drochytka ◽  
Vit Cerný ◽  
Karel Kulísek
Keyword(s):  
Heat Treatment ◽  
Fly Ash ◽  
Construction Industry ◽  
Raw Materials ◽  
Exothermic Reaction ◽  
Reaction Heat ◽  
Anthracite Coal ◽  
Concrete Production ◽  
Aerated Concrete ◽  
Cellular Concrete

Burning high-quality anthracite coal produces ash with a high content of unburned residues, which in many cases permanently exceeds 20%. These ashes usually contain high levels of amorphous phase providing the pozzolanic activity, this making them particularly useful if potentially applied in the construction industry. Such potential of effective treatment necessitates reducing the content of unburned residues, the best level here being less than 4% w/w. This paper deals with the results of testing heat treatment of fly ashes particularly using the resources of eastern Slovakia. Tests have shown that tested process of heat treatment can safely reduce the content of unburned residues in fly ash whilst maintaining high levels of the glass phase. Raw materials thus modified meet the requirements for the use in cellular concrete production technology with beneficial use of exothermic reaction heat from fly ash treatment in pre-heating the autoclaves.

Impact of Superplasticizing Agents on Physical and Mechanical Properties of Cellular Concrete

2019 ◽  
Vol 974 ◽  
pp. 181-186
Author(s):  
V.A. Perfilov ◽  
V.V. Gabova ◽  
Inessa A. Tomareva
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Pore Space ◽  
Experimental Studies ◽  
Basalt Fiber ◽  
Physical And Mechanical Properties ◽  
Foam Concrete ◽  
Cellular Concrete

The effect of superplasticizing, foam agents, various fiber aggregates on the physical and mechanical properties of cellular concrete has been studied. The article covers the results of experimental studies conducted to determine the effect of foam agents PO-6 and PB-2000, as well as polymeric and basalt fiber on the pore structure of foam concrete. The dependence between the change in density and strength of cellular concrete and the structure of its pore space has been determined.

EFFECT OF LOAD BEARING MATERIALS ON SUSCEPTIBILITY TO BIOFILMS GROWTH

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Václav Kočí ◽  
Jiří Maděra
Keyword(s):  
Thermal Conditions ◽  
Point Of View ◽  
Climatic Data ◽  
Load Bearing ◽  
Autoclaved Aerated Concrete ◽  
Bearing Materials ◽  
Heat And Moisture Transport ◽  
Aerated Concrete ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

Preventing a biofilms growth on exterior facades of buildings is one of the ways how to preserve the original buildings appearance and thus their proper aesthetical function. Since the biofilms growth is strongly conditioned by the hygric and thermal conditions on the surface, a proper hygrothermal performance and interactions between materials involved is essential. This paper studies an impact of load bearing material on surface conditions on a lime-cement plaster from the point of view of susceptibility to biofilms growth. An influence of autoclaved aerated concrete, solid brick and sandstone is studied when exposed to dynamic boundary conditions in form of reference climatic data. Being obtained using computational modeling of coupled heat and moisture transport, the results revealed a substantial influence in that respect. The best performance exhibited the autoclaved aerated concrete as the duration of convenient conditions for biofilms growth was lower by 40% when compared to solid brick and sandstone.

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