Non-Autoclaved Aerated Concrete Porosity and Factors Affecting it

The total volume of cellular porosity, which comprises pores, interpore partitions, and air-entrained pores, depends on the spatial packing of pores, size distribution, maximum and average size, their shape, and the thickness of interpore partitions. Interpore partitions contain gel and capillary pores, which have a significant impact on the total porosity, thus affecting the operating properties of aerated concrete. This paper presents the calculations of gel, capillary, air, and total porosity in non-autoclaved aerated concrete of average-density grades D100...D1200 for different cement hydration degrees (0.6; 0.8, and 1) and water-cement ratios (0.5; 0.6, and 0.7); calculations use the author-developed methodology. Cement consumption depends on the average-density grade as well as on cement hydration degree. Reducing the latter from 1 to 0.6 in D500 concrete raises cement consumption by 7.4 %; other grades have similar patterns. This is why aerated concrete should be conditioned to maximize the utilization of the binder by enabling its complete hydration. The amount of water in the mixture is what determines the cement consumption and the water-cement ratio, whereby the density of cement dough will not depend on the average-density grade provided that the hydration degree and the WC ratio are constant. The finding is that the ability of cement to form its own pore structure is crucial to D500 and D400 aerated concrete if the mixture has high initial water content.

Download Full-text

Composite Binder for Structural Cellular Concrete

Materials Science Forum ◽

10.4028/www.scientific.net/msf.945.53 ◽

2019 ◽

Vol 945 ◽

pp. 53-58 ◽

Cited By ~ 4

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.

Download Full-text

FOR THE STUDY OF PECULIARITIES OF STRUCTURE FORMATION OF COMPOSITE BINDERS FOR NON-AUTOCLAVED AERATED CONCRETE

Construction Materials and Products ◽

10.34031/2618-7183-2019-2-3-41-47 ◽

2020 ◽

pp. 41-47 ◽

Cited By ~ 1

Author(s):

V. Lesovik ◽

M. Absimetov ◽

M. Elistratkin ◽

S. Shatalova

Keyword(s):

Structure Formation ◽

Raw Materials ◽

Stage Structure ◽

Average Density ◽

Strength Performance ◽

Molding Mixture ◽

Autoclaved Aerated Concrete ◽

Wide Range ◽

Mineral Additive ◽

Aerated Concrete

the basis of the modern market of cellular concrete is autoclaved gas silicate. At the same time, non-autoclaved aerated concrete is largely a more technological material, allowing the variation of its properties within a wide range, having a potentially wider field of application, less costly in the organization of production, which is of great importance for small and medium-sized businesses. The main problem of non-autoclaved aerated concrete is a higher cost of raw materials compared to silicate, and 20...30% lower strength performance. The proposed solution to this problem is the development of special composite binders with a limited content of clinker and mineral additives of various genetic types, taking into account the peculiarities of the two-stage structure formation of the material – gas porization and the formation of the microstructure of the stone. The article deals with some aspects of the interaction in the system “mineral additive – gypsum – by-products of the gas release reaction” in terms of the effect on the viscosity of the swelling mass and the strength of the stone at different times of hardening. Recommendations are given on the preferred compositions of composite binders and dosages of gypsum in the molding mixture when producing a material with an average density in the range of 500...700 kg/m3.

Download Full-text

Mix Ratio Test and Basic Property Analysis for Autoclaved Aerated Concrete (AAC) Block

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.508 ◽

2012 ◽

Vol 446-449 ◽

pp. 508-512

Author(s):

Ze Wu Fu ◽

San Hai Zeng

Keyword(s):

Water Absorption ◽

Absorption Rate ◽

Total Porosity ◽

Concrete Block ◽

Ratio Test ◽

Water Absorption Rate ◽

Autoclaved Aerated Concrete ◽

Aerated Concrete ◽

Ratio Optimization ◽

Production Demand

Through the mix ratio optimization test, the appropriate autoclaved aerated concrete block may be prepared for the production demand, whose technical indexes could satisfy the requirement of national specification. Furthermore, in the light of the research on the property of autoclaved aerated concrete block for this mix ratio, the strength of concrete block would decrease with the increase of total porosity among the pore diameter from 0.5mm to 1.5mm. The autoclaved aerated concrete block possessed the strong capability of absorbing water, so the volume water absorption rate increased quickly at first and then went down furiously, which could make the shrinkage of autoclaved aerated concrete block augment because of the decrease of its water absorption rate.

Download Full-text

Factors affecting the swelling pressure for Jerash expansive soil

Journal of Advanced Sciences and Engineering Technologies ◽

10.32441/jaset.03.02.05 ◽

2021 ◽

Vol 3 (2) ◽

pp. 44-51

Author(s):

Talal Masoud ◽

Abdulrazzaq Jawish Alkherret

Keyword(s):

Water Content ◽

Expansive Soils ◽

Expansive Soil ◽

Swelling Pressure ◽

Dry Density ◽

Initial Water Content ◽

Content Increase ◽

Initial Water ◽

Factors Affecting ◽

Water Content Increase

In this study for factors effecting the swelling pressure of jerash expansive soils were investigated in this study, effect of initial dry density and effect of initial water content on the jerash expansive soil were investigated.It show that as the initial dry density decrease from 1.85 gm/cm3 to1.25 gm/cm3 , the swelling pressure also decrease are from 3.1 to 0.25gm/cm2 also it show that as the initial water content increase from 0%to 15% , the swelling pressure of jerash expansive soil decrease from 2.65 gm/cm2 to 1.35 gm/cm2 .

Download Full-text

WATER ABSORPTION OF AUTOCLAVED AERATED CONCRETE MADE WITH THE USE OF FLY ASH

Modern Technologies and Scientific and Technological Progress ◽

10.36629/2686-9896-2020-1-151-152 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 151-152

Author(s):

Viktoriya Bugaychuk ◽

Al'bina Baranova

Keyword(s):

Fly Ash ◽

Water Absorption ◽

Average Density ◽

Autoclaved Aerated Concrete ◽

Aerated Concrete ◽

The Difference

The results of determining the water absorption of autoclaved gas-ash concretes grades on the average density of D500 and D600 are presented. During the work, it was found that the difference in water absorption between the studied brands by mass is 17.2 %, by volume - 5.3 %.

Download Full-text

ANALYSIS OF THE FACTORS OF INCREASING THE STRENGTH OF THE NON-AUTOCLAVE AERATED CONCRETE

Construction Materials and Products ◽

10.34031/2618-7183-2018-1-1-59-68 ◽

2020 ◽

pp. 59-68

Author(s):

M.Yu. Elistratkin ◽

M. Kozhuhova

Keyword(s):

Building Materials ◽

Pore Space ◽

Average Density ◽

Space Structure ◽

Gas Generator ◽

Autoclaved Aerated Concrete ◽

Pore Space Structure ◽

Mineral Additive ◽

Aerated Concrete ◽

The Creation

non-autoclaved aerated concrete is the only real alternative to gas silicate in the organization of its release on the basis of regional production of small and medium capacity. This will help improve the competitive environment in the building materials market and optimize the cost of construction. Of particular interest is the possibility of expanding the field of application of this material due to a significant increase in strength characteristics, while maintaining its average density in acceptable, in terms of thermal insulation properties, limits - not more than 1000 ... 1100 kg/m3. At a strength level of 10 MPa and above, in combination with dispersed reinforcement or the use of traditional non-metallic reinforcing elements, such aerated concrete can be used as a lightweight structural material for creating power elements of low-rise buildings, including in promising construction printing technologies; devices distributing the load belts; non-removable formwork; porous, stiffening, filling thin-walled tubular structures. The paper presents an assessment of the effectiveness of traditional ways to increase the strength of non-autoclaved aerated concrete. New solutions for the purposeful formation of the pore space structure are proposed and tested due to the creation and use of a gas generator with normalized gas evolution, which allows the creation of pores of a given volume. The key to the economic effectiveness of the proposed solutions is the transition from traditional portland cement to composite binders based on it. The substantiated choice of the amount and composition of the mineral additive makes it possible to optimize the properties of the binder under the particularity of the problem being solved, and to minimize the consumption of cement and chemical modifiers, increase the speed of durability and the final indices of non-autoclaved aerated concrete.

Download Full-text