Study of the Electrical Properties of Aluminate Cement Adhesives for Porcelain Insulators

Electrical properties are one of the essential parameters of cement-based materials used in suspension porcelain insulators. This paper studied the electrical properties of aluminate cement adhesives (ACA) containing silica fume (SF), as well as their compressive strength and porosity. The results indicated that the addition of silica fume improved the resistivity of ACA under a saturated state (relative humidity is 50%). This was mainly attributed to the decrease of the ACA’s pore connectivity due to the SF’s filling effect. However, the early compressive strength of ACA was slightly reduced by the addition of SF. Under an unsaturated state, the ACA’s resistivity without the SF gradually exceeded that with the SF at the extension of drying time. The nuclear magnetic resonance (NMR) results indicated that the addition of SF content increased the ACA’s porosity; for the tiny pores especially, (the size less than 25 nm), this increased by 3.4%. Meanwhile, the addition of SF increased the tortuosity of the ACA’s conductive channels, which could improve its resistivity. Therefore, SF is recommended to be used in cement-based adhesives on insulators to lower the cost and improve the resistivity.

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Research on the Efficient Application of Silica Fume in High-Tech Cement-Based Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.374-377.1537 ◽

2011 ◽

Vol 374-377 ◽

pp. 1537-1540

Author(s):

Dong Lin ◽

Zi Yun Wen

Keyword(s):

Compressive Strength ◽

Silica Fume ◽

Packing Density ◽

Particle Diameter ◽

High Tech ◽

Average Particle ◽

Average Particle Diameter ◽

Cement Based Materials ◽

Pre Treatment

The comparison experiments are carried out at different silica fume dosage between the silica fume with pre-treatment and the silica fume without pre-treatment. The results show that the pre-treatment of silica fume improved the strength greatly and the silica fume dosage corresponding to the strength peak somewhat moved forward from 0.20 for the cement-based materials with pre-treatment of silica fume to 0.21 for the cement-based materials without pre-treatment of silica fume. The particles distribution experiment results indicate that after the pre-treatment of silica fume, the average particle diameter of silica fume reduced from 2.865μｍto 0.151μｍ. Based on Aim-Goff model, it is concluded that the increase in the compressive strength and flextural strength of cement-based materials with pre-treatment of silica fume, are attributed to the dispersion of silica fume agglomeration and the increase in the packing density of the cement-based materials.

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Cost Minimum Proportioning of Non-Slump Concrete Mix Using Genetic Algorithms

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.468-471.50 ◽

2012 ◽

Vol 468-471 ◽

pp. 50-54 ◽

Cited By ~ 1

Author(s):

Md. Moshiur Rahman ◽

Mohd Zamin Jumaat

Keyword(s):

Compressive Strength ◽

Optimization Problem ◽

Constrained Optimization Problem ◽

Nonlinear Constrained Optimization ◽

Constituent Material ◽

Optimization Formulation ◽

Materials Used ◽

The Individual ◽

The Cost ◽

Optimal Quantity

This paper presents a generalized formulation for determining the optimal quantity of the materials used to produce Non-Slump Concrete with minimum possible cost. The proposed problem is formulated as a nonlinear constrained optimization problem. The proposed problem considers cost of the individual constituent material costs as well as the compressive strength and other requirement. The optimization formulation is employed to minimize the cost function of the system while constraining it to meet the compressive strength and workability requirement. The results demonstrate the efficiency of the proposed approach to reduce the cost as well as to satisfy the above requirement.

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Effect of Metallic Inclusions on the Compressive Strength of Cement-Based Materials

Advances in Materials Science and Engineering ◽

10.1155/2018/1617280 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10

Author(s):

Tomáš Ficker

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Mechanical Stability ◽

Transition Zones ◽

Metallic Inclusions ◽

Cement Based Materials ◽

Concrete Materials ◽

Materials Used ◽

The Stability ◽

Critical Limits

In the concrete foundations, materials come into contact with bedrocks. The surfaces of bedrocks are often covered by sharp protrusions called asperities. Although geotechnical engineers have developed a reliable theory for assessing the mechanical stability of rocky terrains, the stability of transition zones between concrete and sharp asperities remains unsolved. Due to the large pressures that exist in these transition zones, the invasive influence of sharp asperities on the integrity of the concrete raises a question about possible changes of the mechanical properties of concrete materials used in foundations. These circumstances have inspired experiments in which metallic needles of various lengths have been embedded into cement-based materials to assess the influence of the needles on the compressive strength. This influence has been quantified, and the critical limits identifying the changes of material integrity have been determined. It has been conjectured that sharp rock asperities or needle-like rods of steel reinforcement in concrete may cause similar changes of material integrity as the metallic needles used in the experiments performed.

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Performance Study of Self-Compacting Concrete by Fly Ash and Silica Fume for Sustainability in Building Construction

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.692.74 ◽

2016 ◽

Vol 692 ◽

pp. 74-81 ◽

Cited By ~ 2

Author(s):

J.R. Thirumal ◽

R. Harish

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Flexural Strength ◽

Silica Fume ◽

High Performance Concrete ◽

Mineral Admixtures ◽

Partial Replacement ◽

Performance Study ◽

Self Compacting Concrete ◽

The Cost

Self – compacting concrete (SCC) is a high – performance concrete that can flow under its own weight to completely fill the form work and self-consolidation without any mechanical vibration. Green concrete is defined as a concrete which uses waste material as at least one of its components, or its production process does not lead to environmental destruction. Such concrete can accelerate the placement, reduce the labor requirements needed for consolidation, finishing and eliminate environmental pollution. One alternative to reduce the cost of self-compacting concrete is the use of mineral admixtures such as silica fume, ground granulated blast furnace slag and fly ash, which is finely, divided materials added to concrete during mixture procedure .When mineral admixtures replace a part of the Portland cement, the cost of self-compacting concrete will be reduced especially if the mineral admixtures are waste or industrial by-product. The various tests for compressive, tensile and flexural strength are determined for various specimens with certain percentages ( 10 % ,30 % ) of replacement like silica fume, fly ash and combination of both fly ash and silica fume. Admixture combination of fly ash and silica fume replacing 30 % results in maximum compressive strength. Admixture of fly ash replacing 10 % results in maximum tensile and flexural strength. In order to make SCC effective, trials can be made with partial replacement of combining silica fume and fly ash to achieve the higher compressive strength. Minimum replacement of fly ash can be investigated to achieve higher tensile and flexural strength .With respect to the above combination of replacement SCC can be dealt with its several specializations to make it effective.

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Parameters Of Technological Processes Reengineering

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2020.04.28-33 ◽

2020 ◽

pp. 28-33

Keyword(s):

Spatial Organization ◽

Parametric Model ◽

Practical Significance ◽

Machine Time ◽

Time Machine ◽

Technological Processes ◽

Technical Capability ◽

Materials Used ◽

The Cost ◽

Qualitative Characteristics

The article is devoted to reengineering of technological processes - a method of their qualitative transformation on an innovative basis, which in turn assumes the availability of tools that make it possible to establish the economic efficiency and technical capability of such transformations of construction production, to identify the effect of their implementation. In this regard, the problem of forming a parametric model of reengineering of construction technological processes, which involves four enlarged groups of indicators that reflect the quantitative and qualitative characteristics of the processes: materials used, working time, machine time, spatial organization, is considered. It is established that parameters can have either an absolute (physical, cost) or relative (point, percentage) expression and also make their own decomposition. The practical significance of the provisions given in the article is determined by the development of methods of technical rationing, which leads to a reduction in the cost and duration of construction.

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Effect of Partial Replacement of Cement with Silica Fume and Cellulose Fibre on Workability & Compressive Strength of High Performance Concrete

Indian Journal Of Applied Research ◽

10.15373/2249555x/july2013/82 ◽

2011 ◽

Vol 3 (7) ◽

pp. 263-264

Author(s):

Pratik Patel ◽

◽

Dr. Indrajit N Patel

Keyword(s):

Compressive Strength ◽

Silica Fume ◽

High Performance ◽

High Performance Concrete ◽

Cellulose Fibre ◽

Partial Replacement

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COMPRESSIVE STRENGTH AND THERMAL CONDUCTIVITY OF WATER AND AIR CURED PORTLAND CEMENT-FLY ASH-SILICA FUME MORTARS

Environmental Engineering and Management Journal ◽

10.30638/eemj.2018.201 ◽

2018 ◽

Vol 17 (9) ◽

pp. 2023-2030

Author(s):

Arnon Chaipanich ◽

Chalermphan Narattha ◽

Watcharapong Wongkeo ◽

Pailyn Thongsanitgarn

Keyword(s):

Thermal Conductivity ◽

Compressive Strength ◽

Fly Ash ◽

Portland Cement ◽

Silica Fume

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A review on the properties, reinforcing effects, and commercialization of nanomaterials for cement-based materials

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0023 ◽

2020 ◽

Vol 9 (1) ◽

pp. 303-322 ◽

Cited By ~ 3

Author(s):

Zhifang Zhao ◽

Tianqi Qi ◽

Wei Zhou ◽

David Hui ◽

Cong Xiao ◽

...

Keyword(s):

Cement Hydration ◽

State Of The Art ◽

Research Progress ◽

Market Survey ◽

Future Perspectives ◽

Nano Silica ◽

Physical Processes ◽

Existing Problems ◽

Cement Based Materials ◽

The Cost

AbstractThe behavior of cement-based materials is manipulated by chemical and physical processes at the nanolevel. Therefore, the application of nanomaterials in civil engineering to develop nano-modified cement-based materials is a promising research. In recent decades, a large number of researchers have tried to improve the properties of cement-based materials by employing various nanomaterials and to characterize the mechanism of nano-strengthening. In this study, the state of the art progress of nano-modified cement-based materials is systematically reviewed and summarized. First, this study reviews the basic properties and dispersion methods of nanomaterials commonly used in cement-based materials, including carbon nanotubes, carbon nanofibers, graphene, graphene oxide, nano-silica, nano-calcium carbonate, nano-calcium silicate hydrate, etc. Then the research progress on nano-engineered cementitious composites is reviewed from the view of accelerating cement hydration, reinforcing mechanical properties, and improving durability. In addition, the market and applications of nanomaterials for cement-based materials are briefly discussed, and the cost is creatively summarized through market survey. Finally, this study also summarizes the existing problems in current research and provides future perspectives accordingly.

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