scholarly journals Lightweight recycled gypsum with residues of expanded polystyrene and cellulose fiber to improve thermal properties of gypsum

2021 ◽  
Vol 71 (341) ◽  
pp. e242
Author(s):  
K.A. De Oliveira ◽  
C.A.B. Oliveira ◽  
J.C. Molina
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Flexural Strength ◽  
Thermal Performance ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Expanded Polystyrene ◽  
Mechanical Resistance ◽  
Matrix Composites ◽  
Recycled Gypsum

In this study, different proportions of gypsum composite reinforced with recycled cellulose fibers and expanded polystyrene were produced to study the properties of thermal conductivity, density, and flexural strength to be used as sealing plates to improve the thermal comfort of buildings. Different gypsum matrix composites were produced with varied proportions of cellulose fiber and expanded polystyrene, to analyze the influence of residues on the properties of the material. The thermal conductivity obtained for composites with greater amounts of expanded polystyrene was 0.18 W/mK, a 48% reduction in relation to plasterboard, improving thermal performance. The flexural strength was also analyzed, which met the minimum strength requirement for use as gypsum composites, however, it is not enough to be used in places that require mechanical resistance, thus it is indicated for sealing plates applications, improving the thermal performance of places where only plasterboard is used.

The Effect of β-SiC Nanowires on the Properties of Al2O3 Composites

2016 ◽  
Vol 690 ◽  
pp. 240-245
Author(s):  
Wasana Khongwong ◽  
Chumphol Busabok
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Flexural Strength ◽  
Bending Test ◽  
Matrix Composites ◽  
Sic Nanowires ◽  
Four Point Bending ◽  
Four Point Bending Test ◽  
Cold Pressed ◽  
The Relationship

To investigate the effect of adding b-SiC nanowires on the properties of the Al2O3 matrix composites, four different amounts of SiC nanowires, 0.05, 0.1, 0.2 and 0.25 wt% were mixed with Al2O3 powder. All mixtures were ball-milled and dried in an oven at a temperature of 120°C. The Al2O3-SiC mixtures were uniaxially pressed into pellets under 5 MPa and were then isostatically cold-pressed (CIP) under a pressure of 200 MPa. Specimens (13 mm in diameter and 2.5 mm in thickness) were sintered in a tube furnace at the temperature of 1400°C for 1 h in Ar atmosphere. Physical and thermal properties of pellet composites were characterized. The bar shape specimens with dimension of 3 mm x 4 mm x 35 mm were prepared for four-point bending test. The relationship between thermal conductivity and flexural strength versus grain connection of composites have been investigated. The results showed that the composites with adding SiC nanowires at 0.05-0.2 wt% possessed lower thermal conductivity than those monolithic Al2O3 specimens. However, the thermal conductivity of the composite specimens with 0.25 wt% SiC nanowires became higher than those of monolithic Al2O3 specimens. The flexural strengths of the composites gradually decreased with the increasing amount of SiC nanowires.

Thermal properties of kinetic spray Al–SiC metal-matrix composite

2003 ◽  
Vol 18 (4) ◽  
pp. 855-860 ◽  
Author(s):  
Gary L. Eesley ◽  
Alaa Elmoursi ◽  
Nilesh Patel
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Spray Deposition ◽  
Deposition Process ◽  
Matrix Composites ◽  
Kinetic Spray ◽  
Compositional Variations

Kinetic spray deposition provides a new means for producing composite materials with tailored physical properties. We report on measurements of the thermal conductivity and thermal-expansion coefficient for several compositional variations of kinetically sprayed Al–SiC metal-matrix composites. As a result of the deposition process, inclusion of SiC particles saturates in the 30–40% volume fraction range.

scholarly journals Physical, mechanical and thermal properties of Crushed Sand Concrete containing Rubber Waste

2018 ◽  
Vol 149 ◽  
pp. 01076
Author(s):  
Guendouz Mohamed ◽  
Boukhelkhal Djamila
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Flexural Strength ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Bulk Density ◽  
Mechanical And Thermal Properties ◽  
The Past ◽  
Rubber Waste ◽  
And Performance

Over the past twenty years, the rubber wastes are an important part of municipal solid waste. This work focuses on the recycling of rubber waste, specifically rubber waste of used shoes discharged into the nature and added in the mass of crushed sand concrete with percentage (10%, 20%, 30% and 40%). The physical (workability, fresh density), mechanical (compressive and flexural strength) and thermal (thermal conductivity) of different crushed sand concrete made are analyzed and compared to the respective controls. The use of rubber waste in crushed sand concrete contributes to reduce the bulk density and performance of sand concrete. Nevertheless, the use of rubber aggregate leads to a significant reduction in thermal conductivity, which improves the thermal insulation of crushed sand concrete.

Thermal Properties of Diamond-Particle-Dispersed Cu-Matrix-Composites Fabricated by Spark Plasma Sintering (SPS)

2010 ◽  
Vol 638-642 ◽  
pp. 2115-2120 ◽  
Author(s):  
Kiyoshi Mizuuchi ◽  
Kanryu Inoue ◽  
Yasuyuki Agari ◽  
Shinji Yamada ◽  
Motohiro Tanaka ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Spark Plasma Sintering ◽  
Packing Density ◽  
Coefficient Of Thermal Expansion ◽  
Diamond Particle ◽  
Holding Time ◽  
Matrix Composites ◽  
Plasma Sintering ◽  
Spark Plasma

Diamond-particle-dispersed copper (Cu) matrix composites were fabricated from Cu-coated diamond particles by spark plasma sintering (SPS) process, and the microstructure and thermal properties of the composites fabricated were examined. These composites can well be consolidated in a temperature range between 973K and 1173K and scanning electron microscopy detects no reaction at the interface between the diamond particle and the Cu matrix. The relative packing density of the diamond-Cu composite increases with increasing sintering temperature and holding time, reaching 99.2% when sintered at a temperature of 1173K for a holding time of 2.1ks. Thermal conductivity of the diamond-Cu composite containing 43.2 vol. % diamond increases with increasing relative packing density, reaching a maximum (654W/mK) at a relative packing density of 99.2%. This thermal conductivity is 83% the theoretical value estimated by Maxwell-Eucken equation. The coefficient of thermal expansion of the composites falls in the upper line of Kerner’s model, indicating strong bonding between the diamond particle and the Cu matrix in the composite.

Physico-Mechanical Properties of Cellulose Fiber-Cement Mortars

2020 ◽  
Vol 838 ◽  
pp. 31-38
Author(s):  
Nadežda Števulová ◽  
Viola Hospodarova ◽  
Vojtěch Václavík ◽  
Tomáš Dvorský
Keyword(s):  
Flexural Strength ◽  
Cellulose Fiber ◽  
Concrete Block ◽  
Cellulose Fibers ◽  
Wood Pulp ◽  
Waste Paper ◽  
Cement Mortars ◽  
Granulated Slag ◽  
Sand Filler ◽  
Ground Limestone

This paper is aimed to investigate the total sand filler replacement by two types of cellulosic fibers (bleached wood pulp - WP and recycled fibers from waste paper - RF) in cement-based mortars. Two different types of cement mortar, one with addition of finely ground limestone and other with powdered granulated slag, were mixed with fibers. The changes in consistency of fresh fiber cement mortars and development of compressive and flexural strength of mortars in dependence on hardening time up to 90 days was studied. The development of compressive and flexural strength with increasing hardening time of cellulose fiber mortars and two binders with different properties confirmed that binder mixtures containing finely ground slag and recycled cellulose fibers achieved higher values of these strength parameters. Also adhesion testing of fiber cement mortars on two substrates (ceramic fitting and aerated concrete block) after 28 days of their application showed better adhesion of cement mortars with finely ground granulated slag on the ceramic fitting surface compared to the mortars containing finely ground limestone. However, any cracks have occurred on both substrates during the maturing of mortars with slag. Based on the above facts, it can be concluded that suitable plaster mixtures for their use in the interior appear the cement recipes with both cellulose fibers (wood pulp and fibers from recycled waste paper) and with finely ground limestone.

Effective thermal properties of grinding wheels and grains

1998 ◽  
Vol 212 (8) ◽  
pp. 661-669 ◽  
Author(s):  
M N Morgan ◽  
W B Rowe ◽  
S C E Black ◽  
D R Allanson
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Boron Nitride ◽  
Thermal Performance ◽  
Cubic Boron Nitride ◽  
Energy Partitioning ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Abrasive Grains ◽  
Effective Thermal Properties

The thermal properties of the grinding wheel are required for energy partitioning in grinding. This paper describes an investigation of the effective thermal properties of alumina and cubic boron nitride (CBN) grinding wheels. Results are presented for a novel sensor that was designed to measure the bulk thermal properties of grinding wheel samples. The effective bulk thermal properties of the grinding wheel and the effective thermal properties of the abrasive grains were also investigated. It was found that the bulk thermal property is dominated by the properties of the bond and does not account for the improved thermal performance of CBN compared with alumina. Values of the effective thermal conductivities for alumina and CBN abrasive grains are therefore proposed. It is concluded that the effective thermal conductivity of the grains is best obtained inversely from grinding experiments.

Mechanical and Thermal Properties of Silicon Nitride Hot Pressed with Adding Rare-Earth Oxides

2005 ◽  
Vol 486-487 ◽  
pp. 181-184 ◽  
Author(s):  
Dae Ho Choi ◽  
Byung Kyu Moon ◽  
Rak Joo Sung ◽  
Seung Ho Kim ◽  
Koichi Niihara
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Flexural Strength ◽  
Grain Growth ◽  
Rare Earth Oxides ◽  
Lattice Oxygen ◽  
Mechanical And Thermal Properties ◽  
Si3n4 Ceramics

Mechanical and thermal properties of Si3N4 ceramics with various rare-earth oxides (La2O3, CeO2, Lu2O3, Dy2O3, Sm2O3, Nd2O3, Yb2O3, and RuO2) were investigated. Flexural strength of silicon nitride with addition of 5vol% Nd2O3, CeO2, Dy2O3, and Sm2O3 showed higher value than that of silicon nitride with Lu2O3 and La2O3 added because they form denser microstructure and smaller elongated grain. Thermal conductivity of silicon nitride with an addition of 5vol% RuO2 was more enhanced than that of silicon nitride added with Nd2O3, Sm2O3, and Dy2O3 because the addition of RuO2 depressed grain growth. It is also associated with lattice oxygen governing thermal conductivity of Si3N4 when added rare-earth oxides.

Preparation and Thermal Properties of Pressureless Sintered AIN/SiC Composites

2015 ◽  
Vol 655 ◽  
pp. 78-81
Author(s):  
Shu He Ai ◽  
Yu Jun Zhang ◽  
Hong Yu Gong ◽  
Qi Song Li
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Property ◽  
Thermal Properties ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Temperature Range ◽  
Sic Composites

AlN/SiC composites with 5 wt.% Y2O3addition were fabricated by pressureless sintering at 1700-1950 oC. The influences of sintering temperature and SiC content on the relative density, mechanical property and thermal conductivity were studied. With sintering temperature increasing from 1700 oC to 1750 oC, the relative density increased significantly to about 98.0%, without evident changes from 1750 oC to 1900 oC, and then decreased slightly at 1950 oC. As SiC content increased, the flexural strength of composites sintered at 1750 oC increased firstly, and then decreased, obtaining a maximum flexural strength of 337 MPa at 20 wt.% SiC content. Meanwhile, the thermal conductivity decreased from 60 W/(m∙K) to 40 W/(m∙K) with SiC content increasing from 0 wt.% to 30 wt.%. Moreover, in the sintering temperature range from 1750 oC to 1950 oC, the thermal conductivity increased from 45 W/(m∙K) to 55 W/(m∙K) for AlN-10 wt.% SiC composites, but decreased from 40 W/(m∙K) to 36 W/(m∙K) for AlN-30 wt.% SiC composites.

scholarly journals Study about concrete with recycled expanded polystyrene

2019 ◽  
Vol 12 (6) ◽  
pp. 1390-1407 ◽  
Author(s):  
C. H. R. CARVALHO ◽  
L. A. C. MOTTA
Keyword(s):  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Performance ◽  
Large Volume ◽  
Large Scale ◽  
Expanded Polystyrene ◽  
Low Density ◽  
Structural Walls ◽  
Physical Density

Abstract This work studied the properties of lightweight concretes with addition of expanded polystyrene (EPS) for structural walls applications. EPS for being a material produced on a large scale and has low density, produces a large volume of waste. These residues are not reused, especially in Brazil. Given that, in order to perform a comparison of the performance of concrete with adding of EPS in pearls and recycled, it have been manufactured five concrete types, a control without addition of EPS and four other samples with two different percentages of EPS. The mechanical (compressive strength) and physical (density, voids content, absorption by immersion and capillarity) properties were evaluated, and tests were carried out to evaluate the thermal performance of the mixtures studied. The concretes with EPS presented compressive strength less than the reference concrete, however, the absorption for capillarity and thermal properties was better in concretes with EPS. It is concluded that it is feasible to replace the EPS in pearls by recycled EPS, due to the close results found.

scholarly journals Manufacturing of porous refractories from Iraqi Kaolin by adding expanded polystyrene waste

2018 ◽  
Vol 16 (37) ◽  
pp. 118-126
Author(s):  
Shihab A. Zaidan
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Linear Shrinkage ◽  
Expanded Polystyrene ◽  
Apparent Porosity ◽  
Final Outcome ◽  
Modulus Of Rupture ◽  
Mechanical And Thermal Properties ◽  
Polystyrene Waste

Fabrication of porous clay refractory insulating specimens from Iraqi kaolin with different percentage of Expanded Polystyrene (EPS) waste crumbs additions were investigated. After mixing and forming by hand molding, the specimens was dried and fired at 1300 oC. The structural, physical, mechanical and thermal properties of the refractory insulating products were measured. Maximum addition of EPS (1.25 wt%) lead to reduce the linear shrinkage to less than 1.7% and increased apparent porosity up to 50 %. As well as, the density, Modulus of rupture and thermal conductivity were reduced to 1.39 g/cm3, 4.1 MPa and 0.21 W/m.K, respectively. The final outcome, addition of EPS showed good results in the formation of pores without distorting the dimensions of specimens and without any cracks. In addition, it is possible to use these thermal insulators at temperatures up to 1300 oC.

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