Effect of carbon reinforcements on selected properties of mortar

2020 ◽  
Vol 17 (4) ◽  
pp. 543-551
Author(s):  
Payman Sahbah Ahmed ◽  
Manar Nazar Ahmed ◽  
Samal Osman Saied
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Carbon Fibers ◽  
Building Materials ◽  
Building Design ◽  
Content Type ◽  
Micro Particles ◽  
Materials Used ◽  
Short Carbon

Purpose The purpose of this research is using materials to improve the thermal insulation, and reducing the cost. A large amount of energy is consumed by masonary due to cooling and heating. Adding material with certain percentages to the building materials is one of the ways to improve the thermal insulation, and these additives should keep as much as possible the mechanical properties of the building materials. Carbon additives are one of commonly used materials to masonry materials. In spite of the many advantages of using carbon fibers and carbon nano tubes (CNTs) to the cementitious materials, they are very expansive and their thermal conductivity is high. Design/methodology/approach In this research charcoal (which is a product of burning process) with very low thermal conductivity and cost in the form of micro particles will be used with mortar and compared with short carbon fibers and multiwall carbon nanotubes (MWCNTs) via thermal conductivity, density and compressive strength tests. This research includes also an effort to build a model of building to evaluate the thermal insulation of the materials used in the practical part. The main building design and performance simulation tool in this research is DesignBuilder. Findings Results showed that adding micro charcoal particles to mortar resulted in improving the thermal insulation and decrease the rate of reduction in the compressive strength compared to other additives, while adding short carbon fibers resulted in improving the thermal insulation and decrease the compressive strength. Adding MWCNT to the mortar had a negative effect on mechanical and physical properties, i.e. compressive strength, density and thermal insulation. Originality/value This paper uses DesignBuilder software to design a model of building made from the materials used in the practical part to predict and evaluate the thermal insulation.

Experimental Study on the Thermal Conductivity of Thermal Insulation Materials Used in Residential Buildings

2014 ◽  
Vol 1025-1026 ◽  
pp. 535-538
Author(s):  
Young Sun Jeong
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Building Materials ◽  
Residential Buildings ◽  
Building Envelope ◽  
Expanded Polystyrene ◽  
Exterior Wall ◽  
Insulation Materials ◽  
Design Documents ◽  
Materials Used

The most basic way to keep comfortable indoor environments for a building’s occupants and save energy for space heating and cooling in residential buildings is to insulate the building envelope. Among the building materials to be used, thermal insulation materials primarily influence thermal performance. In particular, the type, thermal conductivity, density, and thickness of heat insulator, are important factors influencing thermal insulation performance. We investigate the design status of residential buildings which were designed in accordance with the building code of Korea and selected the type of thermal insulation materials applied to the walls of buildings. The present study aims at measuring the thermal conductivity of thermal insulation materials used for building walls of residential buildings. In this study, after collecting the design documents of 129 residential buildings, we investigated the type and thickness of insulation materials on the exterior wall specified in the design documents. As the thermal insulation materials, extruded polystyrene (XPS) board and expanded polystyrene(EPS) board are used the most widely in Korea when designing residential buildings. The thickness of thermal insulation materials applied to the exterior wall was 70mm, most frequently applied to the design. We measured the thermal conductivity and the density of XPS board and EPS board. When the density of XPS and EPS was 30~35 kg/㎥, the thermal conductivity of XPS was 0.0292 W/mK and it of EPS was 0.0316 W/mK.

Structural and Thermal Properties of Hot Pressed Cu/C Matrix Composites Materials Used for the Thermal Management of High Power Electronic Devices

2007 ◽  
Vol 534-536 ◽  
pp. 1505-1508 ◽  
Author(s):  
Pierre Marie Geffroy ◽  
Jean François Silvain
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Carbon Fibers ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Copper Matrix ◽  
Matrix Composites ◽  
Porosity Level ◽  
Materials Used ◽  
Short Carbon

In order to obtain materials for electronic applications that exhibit both excellent thermal conductivity and low coefficient of thermal expansion (CTE), copper matrix composites have been reinforced by short high modulus graphite fibers. The lack of fiber/matrix interaction prevents any degradation of the carbon reinforcement during the elaboration steps and the normal use of these materials. Elaboration conditions, such as mixing conditions of the short carbon fibers and the copper powder, dimension and shape of the two powders, and finally densification atmosphere, temperature, pressure and time, have been optimized. Main parameters involved in the thermal properties of the Cu/C composite materials have been analyzed and adjusted. CTE is mainly related with the carbon volume fraction; CTE ranging from 9 to 13 10-6/°C can be reproductively obtained with carbon volume fraction ranging from 50% to 20%. Thermal conductivity properties are more complex and are linked mainly with 1) the porosity level inside the material, and 2) the orientation, properties and volume fraction of the carbon fibers. For short carbon fibers, in plane thermal conductivity ranging from 200 to 550 W/mK have been reproductively measured associated with thermal conductivity through-thickness ranging from 150 to 300 W/mK.

scholarly journals The effect of adding natural wastes on some properties of gypsum: تأثير إضافة المخلفات الطبيعية على بعض خواص الجبس

2021 ◽  
Vol 5 (5) ◽  
pp. 77-65
Author(s):  
Alaa Ahmad Zohir Kattan, Nada Altonji, Fatima Alsaleh Alaa Ahmad Zohir Kattan, Nada Altonji, Fatima Alsaleh
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Physical Properties ◽  
Thermal Insulation ◽  
Building Materials ◽  
Reference Sample ◽  
Basic Material ◽  
Mechanical And Physical Properties ◽  
Peanut Shells

In this research, the effect of adding some natural wastes to gypsum was studied in order to use them as thermal insulation materials in buildings and to recycle these wastes. Thermal insulation panels were installed from gypsum (as a basic material) and natural wastes (sawdust, peanut shells, wheat straw, cottonwood) at percentages (10, 15, 20) %, and some of their mechanical and physical properties, and their thermal conductivity were studied. The results indicated an improvement in some properties of gypsum after adding wastes, and obtaining thermal building materials that have better properties than the reference sample (gypsum) in some cases. Rough sawdust samples (SdR15, SdR20) achieved the highest compressive strength exceeding (4MPa). The flexural strength was for peanut shells samples (P10:1.76 MPa, P15:1.8 MPa), while the most efficient samples as thermal insulation were ground straw and smooth sawdust samples (SdS15, SdS20, GSt15, GSt20) where their thermal conductivity was (0.194-0.141W/m.K), which makes it acceptable according to the Syrian thermal insulation code.

scholarly journals PENGARUH PENAMBAHAN SERAT ECENG GONDOK PADA KUAT TEKAN PAVING BLOCK K-200

UKaRsT ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 21
Author(s):  
Muttaqin Fauzin Istighfarin ◽  
Rasio Hepiyanto
Keyword(s):  
Compressive Strength ◽  
Water Hyacinth ◽  
Building Materials ◽  
Rigid Pavement ◽  
Cast Concrete ◽  
Additional Water ◽  
Materials Used ◽  
Relationship Of ◽  
Water Hyacinth Fiber

Abstract Paving block is one of the products of building materials used as the top layer of the street structure, compared to other pavements like cast concrete and asphalt, paving block has been widely chosen especially to the streets used to traversed by low-speeed vehicles. This study aims to know and analyze how strong the influence of additional water hyacinth fiber to the compressive strength of K-200 paving block. Method used in this study is experimental method, with the comparison of mix design reffering to the comparison of concrete quality mixture K-200 (SNI 7394-2008). The result is K-200 paving block decreases its compressive strength after given the mixture of water hyacinth fiber. The precentage of the lowest decrease is in the 0,2 mixture of 55,69% and the highest decrease is in the mixture of 0,8 with the decline presentage of of 82,39%. The score of compressive strength for each test object is: Normal of 209,53 kg/cm², 2% of 92,86 kg/cm², 4% of 84,53 kg/cm², 6% of 58,33 kg/cm², and 8% of 36,90 kg/cm². The relationship of non-linear regression can be seen in R² = 1 on  polinomial orde 4. Paving block with with code objects test “Normal” classified as in the quality of paving block B with compressive strength of 209,53 kg/cm² (17,03 Mpa), while for paving block with extra water hyacinth fiber, it is below the compressive strength standard according to SNI 03-0691-1996. Keywords: Rigid Pavement, Paving Block, Water Hyacinth, Compressive Strength.

Cellulose Fibres as a Reinforcing Element in Building Materials

2017 ◽  
Author(s):  
Viola Hospodarova ◽  
Nadezda Stevulova ◽  
Vojtech Vaclavik ◽  
Tomas Dvorsky ◽  
Jaroslav Briancin
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Building Materials ◽  
Reference Sample ◽  
Physical And Mechanical Properties ◽  
Natural Fibre ◽  
Cement Composites ◽  
Cellulose Fibres ◽  
Cellulosic Fibres

Nowadays, construction sector is focusing in developing sustainable, green and eco-friendly building materials. Natural fibre is growingly being used in composite materials. This paper provides utilization of cellulose fibres as reinforcing agent into cement composites/plasters. Provided cellulosic fibres coming from various sources as bleached wood pulp and recycled waste paper fibres. Differences between cellulosic fibres are given by their physical characterization, chemical composition and SEM micrographs. Physical and mechanical properties of fibre-cement composites with fibre contents 0.2; 0.3and 0.5% by weight of filler and binder were investigated. Reference sample without fibres was also produced. The aim of this work is to investigate the effects of cellulose fibres on the final properties (density, water absorbability, coefficient of thermal conductivity and compressive strength) of the fibrecement plasters after 28 days of hardening. Testing of plasters with varying amount of cellulose fibres (0.2, 0.3 and 0.5 wt. %) has shown that the resulting physical and mechanical properties depend on the amount, the nature and structure of the used fibres. Linear dependences of compressive strength and thermal conductivity on density for plasters with cellulosic fibres adding were observed.

Prediction and analysis of compressive strength of recycled aggregate thermal insulation concrete based on GA-BP optimization network

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jinsong Tu ◽  
Yuanzhen Liu ◽  
Ming Zhou ◽  
Ruixia Li
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Bp Neural Network ◽  
Back Propagation ◽  
Training Sample ◽  
Recycled Aggregate ◽  
Generalization Performance ◽  
Content Type

Purpose This paper aims to predict the 28-day compressive strength of recycled thermal insulation concrete more accurately. Design/methodology/approach The initial weights and thresholds of BP neural network are improved by genetic algorithm on MATLAB 2014 a platform. Findings Genetic algorithm–back propagation (GA-BP) neural network is more stable. The generalization performance of the complex is better. Originality/value The GA-BP neural network based on the training sample data can better realize the strength prediction of recycled aggregate thermal insulation concrete and reduce the complex orthogonal experimental process. GA-BP neural network is more stable. The generalization performance of the complex is better.

Carbon fiber reinforced tin-superconductor composites

1989 ◽  
Vol 4 (6) ◽  
pp. 1339-1346 ◽  
Author(s):  
C. T. Ho ◽  
D. D. L. Chung
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Tensile Modulus ◽  
Tensile Load ◽  
Tensile Fracture ◽  
Fiber Direction ◽  
Continuous Carbon Fiber

Unidirectional and continuous carbon fiber tin-matrix composites were used for the packaging of the high-temperature superconductor YBa2Cu3O7–δ by diffusion bonding at 170 °C and 500 psi. Tin served as the adhesive and to increase the ductility, the normal-state electrical conductivity, and the thermal conductivity. Carbon fibers served to increase the strength and the modulus, both in tension along the fiber direction and in compression perpendicular to the fiber layers, though they decreased the strength in compression along the fiber direction. Carbon fibers also served to increase the thermal conductivity and the thermal fatigue resistance. At 24 vol. % fibers, the tensile strength was approximately equal to the compressive strength perpendicular to the fiber layers. With further increase of the fiber content, the tensile strength exceeded the compressive strength perpendicular to the fiber layers, reaching 134 MPa at 31 vol. % fibers. For fiber contents less than 30 vol. %, the compressive ductility perpendicular to the fiber layers exceeded that of the plain superconductor. At 30 vol. % fibers, the tensile modulus reached 15 GPa at room temperature and 27 GPa at 77 K. The tensile load was essentially sustained by the carbon fibers and the superconducting behavior was maintained after tension almost to the point of tensile fracture. Neither Tc nor Jc was affected by the composite processing.

Study and Application of Plastic Construction Materials

2011 ◽  
Vol 99-100 ◽  
pp. 1117-1120 ◽  
Author(s):  
Mao Quan Xue
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
Energy Saving ◽  
Thermal Insulation ◽  
Flame Retardancy ◽  
Building Materials ◽  
Construction Materials ◽  
Low Thermal Conductivity ◽  
Building Walls

As new building materials, plastic has light weigh, corrosion resistance, low thermal conductivity, thermal insulation, waterproof, energy-saving, molding convenient, high recycling characteristic, widely used in building materials. According to the research of improving its flame retardancy, strength, thermal insulation, waterproof properties, the application of plastic use in doors and windows, pipeline, building walls and roofs of buildings, etc. were reviewed, and the developing direction was discussed.

A Study on Chemical Foaming Geopolymer Building Materials

2013 ◽  
Vol 853 ◽  
pp. 202-206 ◽  
Author(s):  
Tsung Yin Yang ◽  
Chuan Chi Chien
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Sound Absorption ◽  
Building Materials ◽  
Reaction Rate ◽  
Hydrogen Gas ◽  
Aluminum Powders ◽  
Foaming Agents ◽  
Low Thermal Conductivity ◽  
Base Solution

Zinc and aluminum powders were used as foaming agents and organosilane was innovatively used as a modifier to synthesize a foamed geopolymer. The produced foamed geopolymer with enhanced compressive strength and low thermal conductivity is an ideal material for fire protection, sound absorption and thermal insulation. The low thermal conductivity was achieved by increasing the porosity in the foamed geopolymer and the enhanced compressive strength was realized by adding the modifier. The pore numbers in the foamed geopolymer were greatly increased by releasing the hydrogen gas, which was produced from the chemical reaction of zinc and aluminum powders in a base solution. The modifier decreased the foaming reaction rate and generated homogeneously-distributed small pores in the foamed geopolymer with improved compressive strength.

Friction and Wearing Behaviour of Sintered Composites Made from Copper Mixed with Carbon Fibers

2015 ◽  
Vol 660 ◽  
pp. 81-85 ◽  
Author(s):  
Radu Caliman
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Composite Materials ◽  
Friction Coefficient ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Coefficient Of Thermal Expansion ◽  
Density Ratio ◽  
Point Of View ◽  
Short Carbon

This paper presents a study regarding friction and wear comportment of sintered composite materials obtained by mixture of copper with short carbon fibers. Sintered composites are gaining importance because the reinforcement serves to reduce the coefficient of thermal expansion and increase the strength and modulus. In case of composites form by carbon fiber and copper, the thermal conductivity can also be enhanced. The combination of low thermal expansion and high thermal conductivity makes them very attractive for electronic packaging. Besides good thermal properties, their low density makes them particularly desirable for aerospace electronics and orbiting space structures. Compared to the metal itself, a carbon fiber-copper composite is characterized by a higher strength-to-density ratio, a higher modulus-to-density ratio, better fatigue resistance, better high-temperature mechanical properties and better wear resistance. Varying the percentage of short carbon fibers from 7,8% to 2,4%, and the percentage of copper from 92,2% to 97,6%, five dissimilar composite materials have been made and tested from the wear point of view. Friction tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured using abrasive discs made from steel 4340 having the average hardness of 40 HRC, and sliding velocity of 0,6 m/sec. The primary goal of this study work it was to distinguish a mixture of materials with enhanced friction and wearing behaviour. The load applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed.

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