Technological approaches to directed structure formation of construction nanocomposites with increased corrosion resistance

Sinitsin, D.A.; Khalikov, R. M.; Bulatov, B.G.; Galitskov, K.S.; Недосеко, И В

doi:10.15828/2075-8545-2019-11-2-153-164

Cited by 2 publications

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“…The MIP measurements in the present study, as well as those of other authors [36,46,47,48], confirm that total porosity decreases significantly in the presence of NS in the cement matrix, when the optimal amount of NS is incorporated. Therefore, as reported in this study, NS-modified composites exhibit denser microstructures with lower water absorption, which might potentially prevent the ingress of aggressive solutions to the pore structure [12,14,49,50,51]. However, it should be highlighted that exceeding the optimal amount of NS can contribute to worsening some concrete properties; that is, mechanical properties (via the creation of agglomerates), despite the positive effects of the presence of NS on other properties (transport properties).…”

Section: Discussionmentioning

confidence: 83%

Influence of Nanosilica on Mechanical Properties, Sorptivity, and Microstructure of Lightweight Concrete

et al. 2019

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This study presents the results of an experimental investigation of the effects of nanosilica (NS) on the strength development, transport properties, thermal conductivity, air-void, and pore characteristics of lightweight aggregate concrete (LWAC), with an oven-dry density <1000 kg/m3. Four types of concrete mixtures, containing 0 wt.%, 1 wt.%, 2 wt.%, and 4 wt.% of NS were prepared. The development of flexural and compressive strengths was determined for up to 90 days of curing. In addition, transport properties and microstructural properties were determined, with the use of RapidAir, mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) techniques. The experimental results showed that NS has remarkable effects on the mechanical and transport properties of LWACs, even in small dosages. A significant improvement in strength and a reduction of transport properties, in specimens with an increased NS content, was observed. However, the positive effects of NS were more pronounced when a higher amount was incorporated into the mixtures (>1 wt.%). NS contributed to compaction of the LWAC matrix and a modification of the air-void system, by increasing the amount of solid content and refining the fine pore structure, which translated to a noticeable improvement in mechanical and transport properties. On the other hand, NS decreased the consistency, while increasing the viscosity of the fresh mixture. An increment of superplasticizer (SP), along with a decrement of stabilizer (ST) dosages, are thus required.

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Section: Discussionmentioning

confidence: 83%

Influence of Nanosilica on Mechanical Properties, Sorptivity, and Microstructure of Lightweight Concrete

et al. 2019

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“…Today, the construction industry is solving a high-priority task of developing effective recommendations to prevent the corrosion-induced failure of reinforced concrete structures, and the solution should be based on both classical and the most recent theoretical and experimental studies [ 1 , 2 , 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

An Engineering Method of Analyzing the Dynamics of Mass Transfer during Concrete Corrosion Processes in Offshore Structures

et al. 2023

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The environment of an underground structure is much more complex than the above-ground environment. Erosion processes are underway in soil and groundwater; groundwater seepage and soil pressure are also typical for underground environments. Alternating layers of dry and wet soil have a strong effect on concrete, and they reduce its durability. Corrosion of cement concretes is caused by the diffusion of free calcium hydroxide, located in the pores of concrete, from the volume of the cement stone to its surface, bordering on an aggressive environment, and the further transition of the substance through the phase boundary solid (concrete)–soil-aggressive environment (liquid). Due to the fact that all minerals in cement stone exist only in saturated or close-to-saturated solutions of calcium hydroxide, a decrease in the content of which in the pores of concrete as a result of mass transfer processes causes a change in the phase and thermodynamic equilibrium in the body of concrete and leads to the decomposition of highly basic compounds of cement stone and, consequently, to the deterioration of the mechanical properties of concrete (reduction in strength, modulus of elasticity, etc.). A mathematical model of mass transfer in a two-layer plate imitating the “reinforced concrete structure—layer of the soil–coastal marine area” system is proposed as a system of nonstationary partial derivative differential equations of the parabolic type with Newmann’s boundary conditions inside the building and at the interface between the soil and the marine environment and with conjugating boundary conditions at the interface between the concrete and the soil. When the boundary problem of mass conductivity in the “concrete–soil” system is solved, expressions are obtained to determine the dynamics of the concentration profiles of the target component (calcium ions) in the volumes of the concrete and soil. As a result, one can select the optimum composition of concrete, having high anticorrosion properties, to extend the durability of the concrete constructions of offshore marine structures.

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Technological approaches to directed structure formation of construction nanocomposites with increased corrosion resistance

Cited by 2 publications

References 0 publications

Influence of Nanosilica on Mechanical Properties, Sorptivity, and Microstructure of Lightweight Concrete

Influence of Nanosilica on Mechanical Properties, Sorptivity, and Microstructure of Lightweight Concrete

An Engineering Method of Analyzing the Dynamics of Mass Transfer during Concrete Corrosion Processes in Offshore Structures

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