Influence of Recipe Factors on the Structure and Properties of Non-Autoclaved Aerated Concrete of Increased Strength

One of the most promising ways to solve the problem of reducing the rate of depletion of natural non-renewable components of concrete is their complete or partial replacement with renewable plant counterparts that are industrial and agricultural waste. The research significance of this article lies in the determination at the micro- and macro-levels of the principles of the relationship between the composition, the process of structure formation and the formation of properties of concrete based on coconut shells (CSs), as well as the substantiation at the micro- and macro-levels of the effectiveness of such a solution from the point of view of fundamental and applied materials science. The aim of this study was to solve the problem of substantiating the feasibility of concrete consisting of a mineral cement–sand matrix and aggregate in the form of crushed CS, as well as finding a rational combination of components and studying the structure and characteristics of concrete. Test samples were manufactured with a partial substitution of natural coarse aggregate with CS in an amount from 0% to 30% in increments of 5% by volume. The following main characteristics have been studied: density, compressive strength, bending strength and prism strength. The study used regulatory testing and scanning electron microscopy. The density of concrete decreased to 9.1% with increasing the CS content to 30%. The highest values for the strength characteristics and coefficient of construction quality (CCQ) were recorded for concretes containing 5% CS: compressive strength—38.0 MPa, prism strength—28.9 MPa, bending strength—6.1 MPa and CCQ—0.01731 MPa × m3/kg. The increase in compressive strength was 4.1%, prismatic strength—4.0%, bending strength—3.4% and CCQ—6.1% compared with concrete without CS. Increasing the CS content from 10% to 30% inevitably led to a significant drop in the strength characteristics (up to 42%) compared with concrete without CS. Analysis of the microstructure of concrete containing CS instead of part of the natural coarse aggregate revealed that the cement paste penetrates into the pores of the CS, thereby creating good adhesion of this aggregate to the cement–sand matrix.

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“…The coefficient of constructive quality ( CCQ R ) determined by compressive strength R was calculated by Formula (5):

where R is compressive strength (MPa) and ρ is the density of hardened concrete (g/cm 3 ) [ 61 , 62 ].…”

Section: Methodsmentioning

confidence: 99%

Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate

et al. 2023

Self Cite

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“…The authors declare no conflicts of interest. 1 ORCID: 0000-0002-8248-5050 2 ORCID: 0000-0003-0850-9365 3 ORCID: 0000-0003-4871-3504 4 ORCID: 0000-0003-2056-9176 5 ORCID: 0000-0002-1095-7311 Поступила 21.12.2023, одобрена 22.01.2024, принята 5.02.2024…”

Section: авторы заявляют об отсутствии конфликта интересовunclassified

“…По способу производства различают автоклавный газобетон (АГ) и неавтоклавный газобетон (НАГ). Производство НАГ не требует среды насыщенного пара под давлением, что дорого и требует больших энергозатрат, поэтому для многих применений НАГ предпочтителен [4,5].…”

Section: Introductionunclassified

Effect of Nanostructured Additive Based on Graphene Oxide and Lignosulphonate on Water Absorption and Thermal Conductivity of Non-Autoclaved Aerated Concrete

Aljaboobi,

Burakova,

Burakov

et al. 2024

Liq. Cryst. and their Appl.

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The assessment of the effect of various modifiers introduced into the composition of non-autoclaved aerated concrete (NAC) was made. The modifiers were graphene oxide (GO) in the form of an aqueous suspension, lignosulfonate (LS) and a complex GO/LS additive. The samples of gas blocks containing GO – 0.0001, 0.0002, 0.003 wt. %; LS – 0.032, 0.16, 0.32 wt. % by weight of cement and their various combinations were molded. Thermal conductivity and water absorption tests were carried out on the samples of standard and modified NAC aged for 28 days. The research results confirmed the positive effect of reducing thermal conductivity and water absorption, which varied depending on the amount and type of additive. After the addition of LS, GO and GO/LS (0.0002/0.16 wt. %) modifiers, there was a corresponding reduction in water absorption by 12–34 %, 30–50 % and 63 %, respectively, and a decrease in the thermal conductivity coefficient by 6–12 %, 14–18 %, and 29 %, respectively. It is assumed that the introduction of the complex nanomodifier GO/LS increases the degree of crystallinity and homogeneity, as well as changes the composition and size of mineral neoformations of cement stone. Consequently, by changing the structure of silicate matrix through the addition of a modifyer developed by the authors, an improvement in the performance properties of thermal insulating cellular concrete was achieved.

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“…In recent years, natural resources such as shale oil and gas have garnered significant attention from scholars due to the shifting dynamics of global energy resource consumption and the efficient development and utilization of unconventional resources [1][2][3][4]. Notably, China has reported proven recoverable reserves of shale gas amounting to 35 × 10 8 t since 2020 [5].…”

Section: Introductionmentioning

confidence: 99%

Experimental Water Activity Suppression and Numerical Simulation of Shale Pore Blocking

Shan,

Zhao,

Liu

et al. 2023

Processes

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The nanoscale pores in shale oil and gas are often filled with external nanomaterials to enhance wellbore stability and improve energy production. And there has been considerable research on discrete element blocking models and simulations related to nanoparticles. In this paper, the pressure transmission experimental platform is used to systematically study the influence law of different water activity salt solutions on shale permeability and borehole stability. In addition, the force model of the particles in the pore space is reconstructed to study the blocking law of the particle parameters and fluid physical properties on the shale pore space based on the discrete element hydrodynamic model. However, the migration and sealing patterns of nanomaterials in shale pores are unknown, as are the effects of changes in particle parameters on nanoscale sealing. The results show that: (1) The salt solution adopts a formate system, and the salt solution is most capable of blocking the pressure transmission in the shale pores when the water activity is 0.092. The drilling fluid does not easily penetrate into the shale pore space, and it is more capable of maintaining the stability of the shale wellbore. (2) For the physical blocking numerical simulation, the nanoparticle concentration is the most critical factor affecting the shale pore blocking efficiency. Particle size has a large impact on the blocking efficiency of shale pores. The particle diameter increases by 30% and the pore-blocking efficiency increases by 13% when the maximum particle size is smaller than the pore exit. (3) Particle density has a small effect on the final sealing effect of pore space. The pore-plugging efficiency is only increased by 4% as the particle density is increased by 60%. (4) Fluid viscosity has a significant effect on shale pore plugging. The increase in viscosity at a nanoparticle concentration of 1 wt% significantly improves the sealing effectiveness, specifically, the sealing efficiency of the 5 mPa-s nanoparticle solution is 16% higher than that of the 1 mPa-s nanoparticle solution. Finally, we present a technical basis for the selection of a water-based drilling fluid system for long horizontal shale gas drilling.

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Influence of Recipe Factors on the Structure and Properties of Non-Autoclaved Aerated Concrete of Increased Strength

Cited by 9 publications

References 61 publications

Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate

Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate

Effect of Nanostructured Additive Based on Graphene Oxide and Lignosulphonate on Water Absorption and Thermal Conductivity of Non-Autoclaved Aerated Concrete

Experimental Water Activity Suppression and Numerical Simulation of Shale Pore Blocking

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