Effects of carbon nanotubes on expanded glass and silica aerogel based lightweight concrete

Adhikary, Suman Kumar; Rudžionis, Žymantas; Tučkutė, Simona; Ashish, Deepankar Kumar

doi:10.1038/s41598-021-81665-y

Cited by 64 publications

(24 citation statements)

References 52 publications

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“…Recent publications suggest also that the enhancement of the mechanical parameters with retained insulating properties might be achieved by adding other lightweight aggregates along with the aerogel [ 76 , 87 , 90 , 94 , 95 , 96 , 97 , 98 ]. Aggregates used in these solutions include expanded cork, expanded polystyrene, expanded glass or expanded perlite and vermiculite.…”

Section: Composition Mechanical and Insulating Properties Of Cementit...mentioning

confidence: 99%

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

2022

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This paper presents an analysis of research results for silica aerogel cement composites over the past twenty years. Recently, two trends in the development of these composites have been noted, towards structural applications and towards ultralight composites for coatings and renders. Ongoing research shows that important aspects of cementitious composites with good mechanical performance are the proper selection of aggregates and improved adhesion at the silica aerogel–cement binder interface, which will guarantee high compressive strength with the lowest possible thermal conductivity. The best physicomechanical performance of aerogel cement composites with low thermal conductivity below 0.03 W/(m·K) was obtained when cenospheres and aerogel were used in a weight percentage of 5%. In turn, the prerequisites for using aerogel cement composites as coatings for energy-efficient building façades are the use of large amounts of silica aerogel as a substitute for lightweight aggregates or the selection of an optimal composition of lightweight aggregates and aerogel, ensuring the lowest possible thermal conductivity coefficient. Other important standpoints are water transport and moisture protection of the silica aerogel-based coatings. Therefore, in recent years, more and more elements of the hygrothermal performance, porosity and durability of silica aerogel cement composites have been developed. The article also points out the weaknesses of the application of silica aerogel in the cement matrix, the most important of which are the lack of adhesion at the boundary of the aerogel–cement binder, the increased porosity of the composite, the high water absorption capacity and the significant decrease in compressive strength with large volumes of silica aerogel. Solving these issues will certainly contribute to the wider applicability of these materials in the construction industry.

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Section: Composition Mechanical and Insulating Properties Of Cementit...mentioning

confidence: 99%

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

2022

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“…Although normal-weight aggregate concrete performed better, lightweight aggregate concrete weighed less and had a positive effect on the environment [ 11 ], lower early age autogenous shrinkage [ 12 ], relatively good thermal insulation performance [ 13 ], less detrimental impacts of solid waste on the environment, and also addressed the shortage of natural resources [ 14 ]. Some scholars have discussed the influence of substitution rate [ 8 ], shape [ 15 ], materials [ 16 ], and type [ 17 ] of the ceramsite, silica fume [ 18 ], and CNTs [ 19 ] on the compressive strength of lightweight aggregate concrete.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Ceramsite Granules in Lightweight Concrete Panels through an Image Analysis Technique

Yang

Лю

et al. 2022

Materials

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Ceramsite particles are an important component of lightweight ceramsite concrete wall panels, and the density of the aggregate is much lower than the density of the slurry. It is generally accepted that there are inhomogeneities in the distribution of ceramsite particles in wall panels. Ceramsite concrete wallboard material is a research hotspot in the field of fabricated building materials at home and abroad; however, there is no effective way to quantify their inhomogeneity. Based on the application of image recognition technology in concrete homogeneity, a method to quantitatively evaluate the distribution of light aggregates in wall panels was developed. Three commercial lightweight vitrified concrete wall panels were cut into 324 cubes. The four cut surfaces of each specimen were photographed to analyze the proportion of ceramsite particle area, while the density, ultrasonic pulse velocity, and compressive strength of the specimens were tested. The results demonstrated that the image analysis method could effectively describe the homogeneity of the panels. The proportion of particle area of aggregate in the section of the cube had a strong correlation with the compressive strength, ultrasonic pulse velocity, and density, and there was an obvious linear relationship with the height of the plate where the cube was located. Based on this, the correlation equations of the proportion of particle area of aggregate, density, ultrasonic pulse velocity, compressive strength, and the height where the specimen was located were proposed. The quantitative parameters of the relevant properties of the wall panels were also obtained: the maximum difference between the proportion of particle area of the aggregate was 24%, the maximum difference between the density at the top and bottom of the wall panels was 115 kg/m3, and the maximum difference in the strength reached 5 MPa.

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“…Aerogels are materials with excellent features, such as large specific surface area (500–1200 m 2 /g), high porosity (80–99.8%), and low density (0.003–0.5 g/cm 3 ) [ 1 ], which make them readily applicable in adsorption [ 2 , 3 ], heat preservation [ 4 , 5 ], and catalysis [ 6 , 7 ]. However, as ultra-porous materials, aerogels are often highly brittle, especially in the case of a three-dimensional gel skeleton composed of nanoparticles, e.g., silica and other inorganic oxide aerogels [ 8 ]. This poor mechanical property is mainly due to the very small connection area between the nanoparticles that make up the gel skeleton [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Robust Silica-Bacterial Cellulose Composite Aerogel Fibers for Thermal Insulation Textile

Sai

Wang

Miao

et al. 2021

Gels

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Aerogels are nanoporous materials with excellent properties, especially super thermal insulation. However, owing to their serious high brittleness, the macroscopic forms of aerogels are not sufficiently rich for the application in some fields, such as thermal insulation clothing fabric. Recently, freeze spinning and wet spinning have been attempted for the synthesis of aerogel fibers. In this study, robust fibrous silica-bacterial cellulose (BC) composite aerogels with high performance were synthesized in a novel way. Silica sol was diffused into a fiber-like matrix, which was obtained by cutting the BC hydrogel and followed by secondary shaping to form a composite wet gel fiber with a nanoscale interpenetrating network structure. The tensile strength of the resulting aerogel fibers reached up to 5.4 MPa because the quantity of BC nanofibers in the unit volume of the matrix was improved significantly by the secondary shaping process. In addition, the composite aerogel fibers had a high specific area (up to 606.9 m2/g), low density (less than 0.164 g/cm3), and outstanding hydrophobicity. Most notably, they exhibited excellent thermal insulation performance in high-temperature (210 °C) or low-temperature (−72 °C) environments. Moreover, the thermal stability of CAFs (decomposition temperature was about 330 °C) was higher than that of natural polymer fiber. A novel method was proposed herein to prepare aerogel fibers with excellent performance to meet the requirements of wearable applications.

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Effects of carbon nanotubes on expanded glass and silica aerogel based lightweight concrete

Cited by 64 publications

References 52 publications

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

Research Development in Silica Aerogel Incorporated Cementitious Composites—A Review

Quantification of Ceramsite Granules in Lightweight Concrete Panels through an Image Analysis Technique

Robust Silica-Bacterial Cellulose Composite Aerogel Fibers for Thermal Insulation Textile

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