scholarly journals Thermal properties of polypropylene and high modulus polyethylene fibers reinforced concretes

2020 ◽  
Vol 13 (1) ◽  
pp. 32-38
Author(s):  
J. C. AMARAL JR ◽  
W. G. MORAVIA
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Construction Industry ◽  
Polymer Fibers ◽  
High Modulus ◽  
Modulus Polyethylene ◽  
Polyethylene Fibers

Abstract Concrete is one of the materials most used by the construction industry. Reinforcing this material with fibers is a technique used to improve its mechanical properties. Steel and polymer fibers are the main types used in this application and there are few studies about the influence of polymer fibers on the thermal properties of concrete. In order to analyze this influence, the present work carried out thermal conductivity, thermal expansion, and compressive strength after exposure to a temperature of 200 °C on specimens made of concrete with addition of polypropylene (PP) fibers and concrete with addition of high modulus polyethylene (HMPE). It was also conducted thermogravimetric analysis (TGA) on PP and HMPE fibers. The results show that the addition of polymer fibers alters the thermal properties of the concrete, reducing its thermal expansion, for example.

scholarly journals Adequate Correlation between the Physical and Mechanical Properties of Glass Foam

2021 ◽  
Vol 1 (4) ◽  
pp. 14-26
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Marius Florin Dragoescu ◽  
Felicia Cosmulescu
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Insulation ◽  
Coal Fly Ash ◽  
Physical And Mechanical Properties ◽  
Ceramic Foam ◽  
Glass Waste ◽  
Glass Foam

The paper presents experimental results obtained in the manufacturing process of a glass foam by adequate correlation between its physical and thermal properties (density, porosity, thermal conductivity) and mechanical (compressive strength) by a slight controlled overheating of the foamed material. Using a powder mixture of glass waste (87-91.5 %), coal fly ash (3-9 %) and silicon carbide (4-5.5 %) microwave heated at 935-975 ºC by this unconventional technique, constituting the originality of the work, was obtained a glass-ceramic foam with moderate compressive strength (1.8-2.6 MPa) and very low thermal conductivity (0.058-0.070 W/m·K). The material overheating generated a homogeneous porous structure characterized by closed cells with relatively large dimensions (without the tendency to join neighboring cells) making it difficult to transfer heat across the material. The foamed product is suitable for the manufacture of thermal insulation blocks for the inner or outer walls of the building without excessive mechanical stress, being an advantageous alternative by comparison with known types of polymeric or fiberglass thermal insulation materials.

scholarly journals Adequate Correlation between the Physical and Mechanical Properties of Glass Foam

2021 ◽  
Vol 2 (4) ◽  
pp. 14-26
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Marius Florin Dragoescu ◽  
Felicia Cosmulescu
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Insulation ◽  
Coal Fly Ash ◽  
Physical And Mechanical Properties ◽  
Ceramic Foam ◽  
Glass Waste ◽  
Glass Foam

The paper presents experimental results obtained in the manufacturing process of a glass foam by adequate correlation between its physical and thermal properties (density, porosity, thermal conductivity) and mechanical (compressive strength) by a slight controlled overheating of the foamed material. Using a powder mixture of glass waste (87-91.5 %), coal fly ash (3-9 %) and silicon carbide (4-5.5 %) microwave heated at 935-975 ºC by this unconventional technique, constituting the originality of the work, was obtained a glass-ceramic foam with moderate compressive strength (1.8-2.6 MPa) and very low thermal conductivity (0.058-0.070 W/m·K). The material overheating generated a homogeneous porous structure characterized by closed cells with relatively large dimensions (without the tendency to join neighboring cells) making it difficult to transfer heat across the material. The foamed product is suitable for the manufacture of thermal insulation blocks for the inner or outer walls of the building without excessive mechanical stress, being an advantageous alternative by comparison with known types of polymeric or fiberglass thermal insulation materials.

scholarly journals Thermal and Mechanical Properties of Geopolymers Exposed to High Temperature: A Literature Review

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Rui He ◽  
Nan Dai ◽  
Zhenjun Wang
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
High Temperature ◽  
Mass Loss ◽  
Raw Materials ◽  
Expansion Ratio ◽  
Thermal And Mechanical Properties ◽  
Stress Strain

Geopolymers are prepared by alkali solution-activated natural minerals or industrial waste materials, which have been widely used as new sustainable building and construction materials for their excellent thermal and mechanical properties. The thermal and mechanical properties of geopolymers at high temperature have attracted great attention from many researchers. However, there are few systematic works concerning these two issues. Therefore, this work reviewed the thermal and mechanical behaviors of geopolymers at high temperature. Firstly, the thermal properties of geopolymers in terms of mass loss, thermal expansion, and thermal conductivity after high temperature were explained. Secondly, the mechanical properties of residual compressive strength and stress-strain relationship of fly ash geopolymers and metakaolin geopolymers after high temperature were analyzed. Finally, the microstructure and mineralogical characteristics of geopolymers upon heating were interpreted according to the changes of microstructures and compositions. The results show that the thermal properties of geopolymers are superior to cement concrete. The geopolymers possess few mass loss and a low expansion ratio and thermal conductivity at high temperature. The thermal and mechanical properties of the geopolymers are usually closely related to the raw materials and the constituents of the geopolymers. Preparation and testing conditions can affect the mechanical properties of the geopolymers. The stress-strain curves of geopolymer are changed by the composition of geopolymers and the high temperature. The silicon-type fillers not only improve the thermal expansion of the geopolymers but also enhance mechanical properties of the geopolymers. But, they do not contribute to reducing the thermal conductivity. the different raw materials, aluminosilicate precursor and reinforcement materials, result in different geopolymer damage during the heating. However, phase transitions can occur during the process of heating regardless of the raw materials. The additional performance enhancements can be achieved by optimizing the paste formulation, adjusting the inner structure, changing the alkali type, and incorporating reinforcements.

scholarly journals Enhancing physical-thermal-mechanical properties of fired clay bricks by eggshell as a bio-filler and flux

2019 ◽  
Vol 51 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Nuchnapa Tangboriboon ◽  
Sopita Moonsri ◽  
Atima Netthip ◽  
Watchara Sangwan ◽  
Anuvat Sirivat
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Water Absorption ◽  
Extrusion Process ◽  
Clay Brick ◽  
Clay Bricks ◽  
Low Thermal Expansion ◽  
Thermal Mechanical Properties

Fired clay bio-bricks were prepared by adding eggshell as a bio-filler and flux into earthenware clay compounds via an extrusion process. In this study, the suiTab. conditions for clay bricks preparation were firing at 1000?C for a period of 5 h. Adding 20 wt% eggshell powder into the clay brick yielded good physical-mechanical-thermal properties: high compressive strength and hardness, low thermal expansion coefficient, and low water absorption. The measured compressive strength, hardness, and refractory water absorption were 7.0 MPa, 6.0 HV, and less than 15 wt%, respectively. The obtained clay brick with the eggshell powder added as shown here is potential for uses as bricks for construction and thermal insulation.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

Design, Preparation and Thermal Properties of (La0.4Sm0.5Yb0.1)2Zr2O7 Ceramic for Thermal Barrier Coatings

2012 ◽  
Vol 512-515 ◽  
pp. 469-473 ◽  
Author(s):  
L. Liu ◽  
Z. Ma ◽  
F.C. Wang ◽  
Q. Xu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Rare Earth ◽  
Thermal Expansion Coefficient ◽  
Thermal Barrier Coatings ◽  
Expansion Coefficient ◽  
Phonon Transport ◽  
Thermal Barrier ◽  
Barrier Coatings

According to the theory of phonon transport and thermal expansion, a new complex rare-earth zirconate ceramic (La0.4Sm0.5Yb0.1)2Zr2O7, with low thermal conductivity and high thermal expansion coefficient, has been designed by doping proper ions at A sites. The complex rare-earth zirconate (La0.4Sm0.5Yb0.1)2Zr2O7 powder for thermal barrier coatings (TBCs) was synthesized by coprecipitation-calcination method. The phase, microstructure and thermal properties of the new material were investigated. The results revealed that single phase (La0.4Sm0.5Yb0.1)2Zr2O7 with pyrochlore structure was synthesized. The thermal conductivity and the thermal expansion coefficient of the designed complex rare-earth zirconate ceramic is about 1.3W/m•K and 10.5×10-6/K, respectively. These results imply that (La0.4Sm0.5Yb0.1)2Zr2O7 can be explored as the candidate material for the ceramic layer in TBCs system.

scholarly journals Thermal Properties of Yttrium Aluminum Garnett From Molecular Dynamics Simulations

2011 ◽  
Author(s):  
Majid S. al-Dosari ◽  
D. G. Walker
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Specific Heat ◽  
Molecular Dynamics Simulations ◽  
Yttrium Aluminum Garnet ◽  
System Size ◽  
Yttrium Aluminum ◽  
Dynamics Simulations

Yttrium Aluminum Garnet (YAG, Y3Al5O12) and its varieties have applications in thermographic phosphors, lasing mediums, and thermal barriers. In this work, thermal properties of crystalline YAG where aluminum atoms are substituted with gallium atoms (Y3(Al1−xGax)5O12) are explored with molecular dynamics simulations. For YAG at 300K, the simulations gave values close to experimental values for constant-pressure specific heat, thermal expansion, and bulk thermal conductivity. For various values of x, the simulations predicted no change in thermal expansion, an increase in specific heat, and a decrease in thermal conductivity for x = 50%. Furthermore, the simulations predicted a decrease in thermal conductivity with decreasing system size.

Physical Properties of Building Blocks from Hemp Shives Aggregate and Cementitious Binder, Manufactured in the Expanded Clay (Vibro Pressing) Production Line

2017 ◽  
Vol 908 ◽  
pp. 118-122 ◽  
Author(s):  
Giedrius Balčiūnas ◽  
Viktor Kizinievič ◽  
Justinas Gargasas
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Production Line ◽  
Scientific Literature ◽  
Building Blocks ◽  
Freeze Thaw ◽  
Cementitious Binder ◽  
Pressing Technology

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

scholarly journals Response of Recycled Brick Aggregate Concrete to High Temperatures

2019 ◽  
Vol 8 (10) ◽  
pp. 224-227
Keyword(s):  
Mechanical Properties ◽  
Air Pollution ◽  
Compressive Strength ◽  
Construction Industry ◽  
Fire Performance ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Different Temperatures ◽  
Better Than ◽  
Made In

The abundant availability of demolition waste from construction industry is leading towards a significant problem of disposal, land and air pollution. The natural aggregate resources are also depleting due to development of construction activities. An attempt is made in this study to convert this waste into wealth by substituting the recycled brick from demolition waste to granite aggregate in production of the concrete. The granite aggregate (GA) is replaced with recycled brick aggregate (RBA) by 25% of its weight to produce M15 and M20 grades of concrete. The granite aggregate concrete (GAC) and recycled brick aggregate concrete (RBAC) were subjected to different temperatures between 100 to 1000oC for a duration of 3 hours and the mechanical properties such as compressive strength and flexural strength were examined to assess its fire performance. The response of RBAC is better than GAC at each temperature. The study revealed that the residual strength increases with the increase in grade of concrete at all temperatures.

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