scholarly journals Compressive strength and thermal properties of sand–bentonite mixture

2021 ◽  
Vol 13 (1) ◽  
pp. 988-998
Author(s):  
Mindaugas Zakarka ◽  
Šarūnas Skuodis ◽  
Giedrius Šiupšinskas ◽  
Juozas Bielskus
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Moisture Content ◽  
High Voltage ◽  
Power Lines ◽  
Thermal Resistivity ◽  
Mechanical And Thermal Properties ◽  
Protective Material ◽  
Dry Mixing

Abstract Sand–bentonite mixtures are used in road embankments as a protective material for protecting underground high-voltage cables and utility pipelines supplying water and gas etc. The sand–bentonite mixtures provide benefits while laying high-voltage cables. The purpose of this study is to determine the proportions as well as mechanical and thermal properties of a dry-mixed sand–bentonite mixture and to investigate the suitability of such mixtures for installation around high-voltage underground power lines in road embankments. When selecting a sand–bentonite mixture, the following requirements must be ensured: the compressive strength must be greater than 0.5 MPa after 24 h; the thermal resistivity must be greater than 1.2 K m/W (thermal conductivity 0,833 W/(K m)); and the moisture content of the sand–bentonite mixture must be less than 13%. The following materials were used when selecting the bentonite mixture: bentonite, 0–4.0 mm fraction sand, cement (CEM I 42.5R), and water. In this study, six groups of samples were formed, in which the parts of concrete, sand, cement, and water were added in different proportions. The strength and thermal conductivity of the samples were analyzed. Studies about the use of bentonite around high-voltage cables have revealed the need for wet mixing of bentonite suspensions. The required thermal conductivity properties of the soil were not achieved by dry mixing. This method of mixing can be useful only in cases when the thermal conductivity of the mixed soil is not relevant, because the work can be continued after a day.

scholarly journals Bio-based rigid polyurethane foam prepared from apricot stone shell-based polyol for thermal insulation application – Part 2: Morphological, mechanical, and thermal properties

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6080-6094
Author(s):  
Muhammed Said Fidan ◽  
Murat Ertaş
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Polyurethane Foam ◽  
Flame Retardants ◽  
Compressive Modulus ◽  
Cell Diameter ◽  
Mechanical And Thermal Properties ◽  
Rigid Polyurethane Foam

The procedure for the liquefaction of apricot stone shells was reported in Part 1. Part 2 of this work determines the morphological, mechanical, and thermal properties of the bio-based rigid polyurethane foam composites (RPUFc). In this study, the thermal conductivity, compressive strength, compressive modulus, thermogravimetric analysis, flammability tests (horizontal burning and limited oxygen index (LOI)) in the flame retardants), and scanning electron microscope (SEM) (cell diameter in the SEM) tests of the RPUFc were performed and compared with control samples. The results showed the thermal conductivity (0.0342 to 0.0362 mW/mK), compressive strength (10.5 to 14.9 kPa), compressive modulus (179.9 to 180.3 kPa), decomposition and residue in the thermogravimetric analysis (230 to 491 °C, 15.31 to 21.61%), UL-94 and LOI in the flame retardants (539.5 to 591.1 mm/min, 17.8 to 18.5%), and cell diameter in the SEM (50.6 to 347.5 μm) of RPUFc attained from liquefied biomass. The results were similar to those of foams obtained from industrial RPUFs, and demonstrated that bio-based RPUFc obtained from liquefied apricot stone shells could be used as a reinforcement filler in the preparation of RPUFs, specifically in construction and insulation materials. Moreover, liquefied apricot stone shell products have potential to be fabricated into rigid polyurethane foam composites.

scholarly journals THERMAL PROPERTIES OF MALAYSIAN COHESIVE SOILS

2016 ◽  
Vol 78 (8-5) ◽  
Author(s):  
Adriana Amaludin ◽  
Aminaton Marto ◽  
Muhd. Hatta M. Satar ◽  
Hassanel Amaludin ◽  
Salinah Dullah
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Moisture Content ◽  
Specific Heat ◽  
Cohesive Soil ◽  
Linear Increase ◽  
Thermal Resistivity ◽  
Soil Matrix ◽  
Volumetric Specific Heat ◽  
Shallow Geothermal Energy

The thermal properties of soils surrounding energy piles are required for the efficient and optimal design of shallow geothermal energy pile systems. In this study, the thermal conductivity, thermal resistivity and volumetric specific heat of two types of Malaysian cohesive soil were obtained through a series of laboratory experiments using a thermal needle probe. This study was conducted to determine the effect of moisture content on the thermal conductivity, thermal resistivity and volumetric specific heat values of the cohesive soil at a given value of soil density. For soils with low to medium moisture content, a linear increase in the thermal conductivity and volumetric heat capacity was observed as the moisture content gradually increased, while the thermal resistivity values of the soil had decreased. Meanwhile, for soils with high moisture content, the thermal conductivity was observed to have decreased, and a marked increase was seen in the thermal resistivity. This is due to the disruption of the thermal flow continuity in the soil matrix with the presence of moisture in the soil which adversely affects the thermal conductivity

scholarly journals Physical Properties of Soy-Phosphate Polyol-Based Rigid Polyurethane Foams

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Hongyu Fan ◽  
Ali Tekeei ◽  
Galen J. Suppes ◽  
Fu-Hung Hsieh
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Water Content ◽  
Polyurethane Foams ◽  
Solid Polymer ◽  
Mechanical And Thermal Properties ◽  
Blowing Agent ◽  
Isocyanate Index ◽  
Pu Foams

Water-blown rigid polyurethane (PU) foams were made from 0–50% soy-phosphate polyol (SPP) and 2–4% water as the blowing agent. The mechanical and thermal properties of these SPP-based PU foams (SPP PU foams) were investigated. SPP PU foams with higher water content had greater volume, lower density, and compressive strength. SPP PU foams with 3% water content and 20% SPP had the lowest thermal conductivity. The thermal conductivity of SPP PU foams decreased and then increased with increasing SPP percentage, resulting from the combined effects of thermal properties of the gas and solid polymer phases. Higher isocyanate density led to higher compressive strength. At the same isocyanate index, the compressive strength of some 20% SPP foams was close or similar to the control foams made from VORANOL 490.

Effect of Nanosilica on Mechanical and Thermal Properties of Cement Composites for Thermal Energy Storage Materials

2015 ◽  
Vol 1131 ◽  
pp. 182-185
Author(s):  
Pongsak Jittabut
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Energy ◽  
Energy Storage Materials ◽  
Mechanical And Thermal Properties ◽  
Storage Materials ◽  
Nanosilica Particle

This research article presents the mechanical and thermal properties of cement-based composite for thermal energy storage materials. The effects of nanosilica particle size and concentration determined by mixing nanosilica particle size of 50 nm, using nanosilica were of 1-5 wt%. Thermal properties coefficients were tested using a direct measuring instrument with surface probe (ISOMET2114). The influence of nanosilica on the performance, such as compressive strength, bulk density, thermal conductivity, volume heat capacity and thermal diffusivity of hardened composite cement pastes were studied for future solar thermal energy materials with better performance. According to the development of thermal storage materials and their application environment requirement in solar thermal power, the specimens were subjected to heat at 350, and 900°C. It were observed that, before heating, the compressive strength is optimized at nanosilica amount of 4wt% at the age of 28 days. Moreover, after heating at 350 oC and 900°C, the thermal conductivity and volume heat capacity of the cement paste enriched with nanosilica were significantly lesser than that of the before heating one.

Study of the Impact of Rice Straw Particle Size on the Mechanical and Thermal Properties of Straw Lime Concretes

2022 ◽  
Author(s):  
Youssef El Moussi ◽  
Laurent Clerc ◽  
Jean-Charles Benezet
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Water Absorption ◽  
Rice Straw ◽  
Absorption Capacity ◽  
Mechanical And Thermal Properties ◽  
Water Absorption Capacity ◽  
The Impact

The use of bio-based concretes performed with lignocellulosic aggregates constitute an interesting solution for reducing the energy consumption, greenhouse gas emissions and CO2 generated by the building sector. Indeed, bio-based materials could be used as an alternative of traditional materials such as expended polystyrene and mineral resources (e.g. glass and rock wools) for insulation. Furthermore, these bio-based concretes are known for their interesting insulation properties, indeed they allow to enhance thermal properties of buildings and enables moisture management which lead to design efficient building materials. For this purpose, bio-based concrete using rice straw as aggregate are studied in this present work. The impact of the characteristics of rice straw particle (particle size distribution, bulk density, and water absorption capacity, etc.) on both the mechanical and thermal properties of the bio-based concrete are investigated. Five formulations of rice straw concrete are examined, compared and then classified in terms of insulation properties and mechanical properties. The assessments are based on the measurement of density and thermal conductivity. The variation of compressive strength in function of the characteristics (mean particle length) of rice straw particle are assessed and discussed. The investigation covers also the porosity and density. Tests are also carried out on agricultural by-products with a view to highlight their chemical, physical and structural proprieties. The results show that the use of large particles with low water absorption capacity induce lighter concretes with the density between 339 and 505 kg/m3 and lead to a high compressive strength with a high mechanical deformability. Furthermore, it appears that an increase in the average length of rice straw particle lead to decrease of thermal conductivity of bio-based concretes. It varies from 0.062 to 0.085 W/(m.K).

Mechanical and Thermal Properties of PCM Wallboards Based on Gypsum and Paraffin

2011 ◽  
Vol 71-78 ◽  
pp. 3553-3557
Author(s):  
Xiao Peng Wang ◽  
Zhen Qiu Shen ◽  
Yi Zhang ◽  
Dong Xu Li
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Energy Consumption ◽  
Building Energy ◽  
Building Envelope ◽  
Mechanical And Thermal Properties ◽  
Building Energy Consumption

This paper studied on preparation, mechanical and thermal properties of two PCM wallboards made of gypsum and paraffin composite, PCM particles wallboard and PCM bag packed wallboard. Density, flexural and compressive strength and thermal conductivity of PCM particles wallboards deceased as PCM particles dosage increasing. Only PCM particles wallboard with PCM particles dosage 30% is suitable. Thermal comparison between PCM wallboards and pure gypsum wallboard shows that two PCM wallboards have better thermal properties and PCM wallboards can be used in building envelope to cut down building energy-consumption.

Effect of Nano-TiO2 on Mechanical and Thermal Properties of Cement Composites for Thermal Energy Storage Materials

2015 ◽  
Vol 804 ◽  
pp. 115-118
Author(s):  
Pongsak Jittabut
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Storage Materials ◽  
Mechanical And Thermal Properties ◽  
Storage Materials

This research article presents the mechanical and thermal properties of cement-based composite for thermal energy storage materials enriched with containing nanoTiO2 particle size (25 nm) and concentration (1-5 wt.%) were systematically investigated. Thermal properties coefficients were tested using a direct measuring instrument with surface probe (ISOMET2114). The influence of nanoTiO2 on the performance, such as compressive strength, bulk density, thermal conductivity, volume heat capacity and thermal diffusivity of hardened composite cement pastes were studied for future solar thermal energy materials with better performance. According to the development of thermal storage materials and their application environment requirement in solar thermal power, the specimens were subjected to heat at 350°C and 900°C. It was observed that, before heating, the compressive strength is optimized at nanoTiO2 amount of 2 wt%. Moreover, after heating at 350 °C and 900°C, the thermal conductivity and volume heat capacity of the cement paste enriched with nanoTiO2 were significantly lesser than that of the before heating one.

Effect of ZrO2 and MgO Addition on Structure, Mechanical and Thermal Properties of Metakaolin-Based Geopolymer Composites

2019 ◽  
Vol 798 ◽  
pp. 298-303 ◽  
Author(s):  
Rewadee Wongmaneerung
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Phase Formation ◽  
Sodium Hydroxide Solution ◽  
Conductivity Measurement ◽  
Green Building ◽  
Sodium Silicate Solution ◽  
Mechanical And Thermal Properties ◽  
Geopolymer Composites

This research studies the fabrication and properties of reinforced-geopolymer composites for Green Building. The study comprises of phase formation, microstructure, mechanical and thermal properties. Metakaolin-based geopolymer has been fabricated from calcined kaolin at 750 °C for 6 h. Sodium hydroxide solution with 10 M and sodium silicate solution were used as alkaline activators. The ratio between metakaolin and solution was 1:1.25. Two reinforcements; ZrO2 and MgO at the composition of 0, 1, 3, 5, 7 and 9 wt% were added, then well-mixed together. After casting in acrylic mold, samples were cured at 50 °C for 72 h and then stored in air for 7 and 28 days. Phase formation, microstructure, compressive strength and thermal conductivity were determined by XRD, SEM, universal testing and thermal conductivity measurement, respectively. The results revealed that after stored for 28 days, XRD patterns of geopolymer with and without reinforcements show typical amorphous characteristic. Microstructure observation revealed the dense and heterogenous. The addition both of reinforcements has no effect on the geopolymerization reaction. Compressive strength tends to increase with increasing the amount of MgO content. Moreover, thermal conductivity slightly increased with the amounts of ZrO2 and MgO increase.

Lightweight Gypsum-Based Material, Foamed by Lime Dust and Acid Agent

2015 ◽  
Vol 729 ◽  
pp. 3-8
Author(s):  
Mst Nazmunnahar ◽  
Alena Vimmrova
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Bulk Density ◽  
Mechanical And Thermal Properties ◽  
Lightweight Material ◽  
Acid Agent ◽  
Stone Dust

Lightweight gypsum materials foamed by the help of stone dust were investigated. Lightweight material prepared from the gypsum as a main binder and foamed by stone dust and acid agent. The materials with the bulk density are 607 kg/m3, compressive strength about 1.3 MPa and thermal conductivity was prepared. Basic physical, mechanical and thermal properties were investigated.

scholarly journals The Effect of Multiwalled Carbon Nanotubes on the Thermal Conductivity and Cellular Size of Polyurethane Foam

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Huynh Mai Duc ◽  
Dat Nguyen Huu ◽  
Trung Tran Huu ◽  
Lu Le Trong ◽  
Hai Luong Nhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Fourier Transform ◽  
Thermal Properties ◽  
Multiwalled Carbon Nanotubes ◽  
Mechanical And Thermal Properties ◽  
Multiwalled Carbon ◽  
Sem Images ◽  
Pu Foam

Polyurethane (PU) foam is known as the popular material for the applications in many fields of industry and life. To improve the mechanical and thermal properties of this material, in this research, PU foam was reinforced with aniline-modified multiwalled carbon nanotubes (MWCNTs). Fourier transform infrared FTIR spectrum of modified MWCNTs showed the aniline was grafted on the surface of MWCNTs through the appearance of –NH2 stretches. The effect of MWCNTs with and without modification on the density, porosity, compressive strength, and heat conductivity of PU/MWCNT foam nanocomposites was investigated. The dispersibility of MWCNTs in the PU matrix was enhanced after modification with aniline. Compressive strength of PU nanocomposite reached the highest value after adding 3 wt.% of modified MWCNTs into PU foam. Besides, the water uptake of PU nanocomposites using 3 wt.% of MWCNTs was decreased to 13.4% as compared to that using unmodified MWCNTs. The improvement in thermal conductivity of PU/aniline-modified MWCNT nanocomposite was observed due to the change in the cellular size of PU foam in the presence of MWCNTs as shown by SEM images.

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