Structure Formation Features of Non-Autoclaved Gas Concrete Matrix on the Basis of Composite Binders with Various Mineral Additives

2019 ◽  
Vol 974 ◽  
pp. 249-254
Author(s):  
Michail V. Absimetov ◽  
Mikhail Yurievich Elistratkin ◽  
Marina S. Ageeva

One of the effective ways to reduce the material consumption of structures, to save all types of resources due to this, is the transition to porous constructional materials instead of traditional dense materials. In this regard, non-autoclaved gas concrete is of great interest. This material has a high manufacturability and has a good potential for improving the strength properties due to the replacement of traditional portland cement by special composite binders. Available publications confirm the effectiveness and prospects of this direction. An important disadvantage of such works is the fact that the binder indicators and the final cellular concrete characteristics are considered mainly independently. In our opinion, it is more correct to consider at least two structure-forming processes proceeding in parallel and sequentially at different scale levels. Micro level is a stone structure formation based on the composite binder; macro-level is a gas porization of cellular mass concrete. These processes have a great mutual influence on each other, and therefore this article attempts to observe the gassing products effect on the stone hardening based on composite binders, as well as the composite binder makeup on the viscosity change of the molding compound, as an important condition for the formation of high-quality less defective pore structure of cellular concrete.

Author(s):  
R. S. Fediuk ◽  
A. V. Baranov ◽  
D. V. Khromenok ◽  
I. R. Zelenskiy ◽  
S. V. Kim

The aim of the paper is to improve the strength properties of cement stone via control for structure formation. The composite binder composition includes the type CEM I 42.5N (58–70%) Portland cement, active silica additive (25–37%), quartz sand (2.5–7.5%) and limestone crushed waste (2.5–7.5%). The optimum technology of mechanochemical activation is proposed for the cement stone. The optimization of the structure formation process is provided by the mineral-mineral modifier, crushed together with Portland cement in a planetary mill to a specific surface of 550 m2/kg. The amorphous phase of silicon dioxide in the composition of the modifier intensifies the calcium hydroxide binding forming during alite hydration. It contributes to the growth in low-basic calcium silicate and lowers the cement stone basicity, while reducing the amount of portlandite. The crystalline phase of β-quartz silicon dioxide plays the role of crystallization centers new formations and the cement stone microstructure compaction. Limestone particles contribute to the formation of calcium hydrocarbonate and act as a microfiller together with fine ground quartz sand clogging the pores in the cement stone.


Holzforschung ◽  
2008 ◽  
Vol 62 (6) ◽  
Author(s):  
Kweonhwan Hwang ◽  
EeDing Wong ◽  
Kohei Komatsu

Abstract A research project has been conducted to develop structural laminated veneer lumber products from tropical wood, and to evaluate their feasibility for the structural components of wooden houses. As part of this project, we investigated the flexural, in-plane shear, and nail shear properties of laminated veneer board (LVB) manufactured from a combination of falcataria (Paraserianthes falcataria) and rubberwood (Hevea brasiliensis) for flooring applications. In addition, 11-ply larch (Larix leptolepis) and 7-ply radiata pine (Pinus radiata) plywood were investigated as controls. Larch plywood, bonded with phenol-based adhesive, showed the best strength properties in bending and shear tests, whereas the 12-ply (28 mm thick) resorcinol-based resin-bonded LVB had the highest ductility in nail shear. The LVB also had better bending and shear properties than radiata pine plywood. In conclusion, falcataria-rubberwood LVB demonstrated good potential to substitute larch plywood and radiata pine plywood in flooring applications.


2019 ◽  
Vol 945 ◽  
pp. 53-58 ◽  
Author(s):  
M.Y. Elistratkin ◽  
E.S. Glagolev ◽  
M.V. Absimetov ◽  
V.V. Voronov

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.


2013 ◽  
Vol 860-863 ◽  
pp. 1323-1326 ◽  
Author(s):  
Mihail Bruyako ◽  
Larisa Stsnislavovna Grigoryeva ◽  
Darya Victorovna Kravtsova

There is mentioned some methods of creation variable density cellular concrete, offered original technique. There are presented some properties of the developed material in comparison with the analogue. Variable density cellular concrete can be described as the material with equal variation of density from its periphery to the center. Potentially it will help to improve strength properties and at the same time to maintain low thermal conductivity value of the variable density units.


2019 ◽  
Vol 91 ◽  
pp. 02024 ◽  
Author(s):  
Ruben Kazaryan ◽  
Konstantin Belyaev

Cellular concrete holds one of the leading places in world practice of construction as a structural heat insulating material used in the construction and reconstruction of buildings and structures for various purposes. Excessive (reserve) porosity of cellular concrete provides its frost resistance (compensates expansion of water when freezing and the formed ice without destroying the material). Vapor permeability of cellular concrete provides fast removal of technological moisture from the material and the maintenance of normal moisture conditions in the rooms, and rather high air permeability contributes to the preservation of fresh air in the rooms. Thermal insulation and strength properties of cellular concrete allow erecting single-layer enclosing structures with the required thermal resistance from it. Cellular concretes are divided into aerated concrete and foam concrete, the operating, physical and mechanical parameters of which are almost the same with all other things being equal. According to the hydrothermal treatment method, cellular concrete is divided into two groups: autoclaved and non-autoclaved concrete (air hardening or steaming). The qualities of such concretes differ significantly, since autoclave treatment changes the mineralogical composition of concrete, which greatly affects the profitability of energy-related technological processes associated with the environment and ultimately forms the basis of environmental planning and management.


1997 ◽  
Vol 123 (2) ◽  
pp. 44-54 ◽  
Author(s):  
Wenyi Hu ◽  
Ronald D. Neufeld ◽  
Luis E. Vallejo ◽  
Christopher Kelly ◽  
Martin Latona

2013 ◽  
Vol 379 ◽  
pp. 101-104
Author(s):  
Mazhyn Skakov ◽  
Lyaila Bayatanova ◽  
Michael Sсheffler

In this paper modified gradient layer was under research, the resulting electrolytic-plasma carbonitriding of low carbon steel 18CrNi3Mo surface was investigated. Aiming to improve the structure and strength properties of the layer, the possibility of application have been shown. Plasma carbonitriding optimized mode is presented as well. Regime of electrolyte plasma carbonitriding which consists in heating the steel sample to 8500C with aggregate exposure at this temperature for 3-7 min. and quenching in cold electrolyte has been optimized. We studied the processes of modified layer structure formation under different conditions


2016 ◽  
Vol 870 ◽  
pp. 248-252 ◽  
Author(s):  
N.S. Klochkov ◽  
U.P. Egorov ◽  
Carlo Mapelli ◽  
Irina K. Zabrodina

The effect of tin and nickel on the structure and properties of the leaded bronze obtained by means of the centrifugal casting has been studied. Regularities of change of strength properties and ductility explain the features of the structure formation under the influence of nickel and tin. The paper demonstrates that introduction of nickel promotes a uniform distribution of the plate-shaped lead in the interdendritic space. Introduction of tin sufficient for the formation of eutectoid results in a uniform and compact arrangement of lead in the intergranular space. Complex alloying with nickel and tin contributes to strength characteristics increase.


2013 ◽  
Vol 315 ◽  
pp. 728-732 ◽  
Author(s):  
N.K. Yusuf ◽  
Mohd Amri Lajis ◽  
M.I. Daud ◽  
Mohamad Zaky Noh

A method of solid-state recycling aluminum alloy using hot press forging process was studied as well as the possibility of the recycled chip to be used as secondary resources. This paper presents the results of recycled AA6061 aluminium alloy chip using different operating temperature for hot press forging process. Mechanical properties and microstructure of the recycled specimens and as-received (reference) specimen were investigated. The recycled specimens exhibit a good potential in the strength properties. The result for yield strength (YS) and ultimate tensile strength (UTS) at the minimum temperature 430°C is 25.8 MPa and 27.13 MPa. For the maximum operating temperature 520°C YS and UTS are 107.0MPa and 117.53 MPa. Analysis for different operating temperatures shows that the higher temperatures giving better result on mechanical properties and finer microstructure. The strength of recycled specimen increases due to the grain refinement strengthening whereas particle dispersion strengthening has minor effects. In this study, the recycled AA6061 chip shows the good potential in strengthening as the comparison of using only 17.5% of suggested pressure (70.0/400.0) MPa, the UTS exhibit 35.8% (117.58/327.69) MPa. This shows a remarkable potential of direct recycling by using hot press forging process.


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