scholarly journals Influence of the Hydric State and Lime Treatment on the Thermal Conductivity of a Calcareous Tufa

2021 ◽  
Vol 7 (3) ◽  
pp. 419-430
Author(s):  
K. Mekaideche ◽  
F-E. M. Derfouf ◽  
A. Laimeche ◽  
N. Abou-Bekr
Keyword(s):  
Thermal Conductivity ◽  
Water Content ◽  
Building Materials ◽  
Degree Of Saturation ◽  
Transient Hot Wire ◽  
Drying Process ◽  
Lime Treatment ◽  
North West ◽  
Calcareous Tufa ◽  
Fired Bricks

An experimental study was conducted to investigate changes of thermal conductivity of a raw and lime-treated calcareous tufa (north-west of Algeria) during drying process. Treated (with 4% of lime) and untreated samples were prepared by static compaction at the Standard Proctor Optimum (SPO), Modified Proctor Optimum (MPO) and at a constant stress level of 4 MPa. Transient Hot Wire (THW) method was used to measure the thermal conductivity and the water content and degree of saturation of samples were determined at various drying times. Results show that the drying process induces a decrease in thermal conductivity. This parameter seems to vary linearly with the water content and the degree of saturation. In addition, it was found that the lime treatment leads also to a decrease in the thermal conductivity. Thus, the drying process and the lime treatment will jointly contribute to the reduction of the thermal conductivity of the studied material in such a way that it is more insulating than some traditional building materials like concrete or fired bricks. Doi: 10.28991/cej-2021-03091663 Full Text: PDF

Research on the Retention Capacity of Ruins Soil under Drying Condition

2014 ◽  
Vol 580-583 ◽  
pp. 705-710
Author(s):  
Ping Liu ◽  
Hu Yuan Zhang ◽  
Yi Chen ◽  
Xian Xian Shao ◽  
Xin Yuan Fu
Keyword(s):  
Water Content ◽  
Void Ratio ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Soil Samples ◽  
Degree Of Saturation ◽  
Drying Process ◽  
Retention Capacity ◽  
Pore Water Pressures ◽  
The Relationship

The soil water characteristic curve (SWCC) has been tested during the drying process. In order to define the relationship between suction, degree of saturation and void ratio, fitting models of SWCC was established. Studies have shown that the shape of SWCC of three kinds of samples (taken from Jiaohe, Gaochang and Jiuzhoutai) was similar to the inverted “S”, the relationship between water content and matric suction was inversely proportional. Under the condition of the same moisture, the matric suction of the Jiaohe and Gaochang samples were greater than the Jiuzhoutai samples, and the changes of pore water pressures showed the same trend. The degree of saturation began to decrease when the water content reduced to the air entry value. When the degree of saturation was greater than 90%, the volume of soil samples contracted significantly, and when saturation is below 80%, volume shrinkage stopped.

Basic Study on Effects of Water Content on Printing Paper on Equivalent Thermal Conductivity

2018 ◽  
Vol 2018 (1) ◽  
pp. 41-43
Author(s):  
Takashi Fukue ◽  
Hirotoshi Terao ◽  
Koichi Hirose ◽  
Tomoko Wauke ◽  
Hisashi Hoshino ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Water Content ◽  
Basic Study ◽  
Equivalent Thermal Conductivity ◽  
Printing Paper

Effect of water content on microwave dielectric properties of building materials

2020 ◽  
Vol 263 ◽  
pp. 120107
Author(s):  
Romain Damez ◽  
Philippe Artillan ◽  
Arthur Hellouin de Menibus ◽  
Cédric Bermond ◽  
Pascal Xavier
Keyword(s):  
Dielectric Properties ◽  
Water Content ◽  
Building Materials ◽  
Microwave Dielectric Properties ◽  
Effect Of Water ◽  
Microwave Dielectric

scholarly journals Apparatus for routine measurements of the thermal conductivity of ice cores

1999 ◽  
Vol 29 ◽  
pp. 151-154 ◽  
Author(s):  
Crescenzo Festa ◽  
Aristide Rossi
Keyword(s):  
Thermal Conductivity ◽  
Ice Cores ◽  
Maximum Temperature ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Standard Samples ◽  
Experimental Conditions ◽  
Heating Source ◽  
Central Segment ◽  
Wire Method

AbstractAn apparatus is described for measuring the thermal conductivity of ice by the transient hot-wire method. Thermal conductivity A, is determined by tracking the thermal pulse induced in the sample by a heating source consisting of a platinum resistor. A central segment of the same platinum heating resistor acts also as a thermal sensor. A heat pulse transferred to the ice for a period of 40s gives a maximum temperature increment of about 7-14°C. In good experimental conditions, the expected reproducibility of the measurements is within ±3%. The accuracy of the method depends on whether the instrument has been calibrated by reliable standard samples, certified by absolute methods.

scholarly journals Testing a Gypsum Composite Based on Raw Gypsum with a Direct Admixture of Paraffin and Polymer to Improve Thermal Properties

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3241
Author(s):  
Krzysztof Powała ◽  
Andrzej Obraniak ◽  
Dariusz Heim
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Phase Change ◽  
Large Scale ◽  
Building Materials ◽  
Residential Buildings ◽  
Energy Performance ◽  
Polymer Content ◽  
Volumetric Heat Capacity

The implemented new legal regulations regarding thermal comfort, the energy performance of residential buildings, and proecological requirements require the design of new building materials, the use of which will improve the thermal efficiency of newly built and renovated buildings. Therefore, many companies producing building materials strive to improve the properties of their products by reducing the weight of the materials, increasing their mechanical properties, and improving their insulating properties. Currently, there are solutions in phase-change materials (PCM) production technology, such as microencapsulation, but its application on a large scale is extremely costly. This paper presents a solution to the abovementioned problem through the creation and testing of a composite, i.e., a new mixture of gypsum, paraffin, and polymer, which can be used in the production of plasterboard. The presented solution uses a material (PCM) which improves the thermal properties of the composite by taking advantage of the phase-change phenomenon. The study analyzes the influence of polymer content in the total mass of a composite in relation to its thermal conductivity, volumetric heat capacity, and diffusivity. Based on the results contained in this article, the best solution appears to be a mixture with 0.1% polymer content. It is definitely visible in the tests which use drying, hardening time, and paraffin absorption. It differs slightly from the best result in the thermal conductivity test, while it is comparable in terms of volumetric heat capacity and differs slightly from the best result in the thermal diffusivity test.

scholarly journals Comparison of the thermal performance between conventional and cob building

2019 ◽  
Vol 111 ◽  
pp. 03003
Author(s):  
Kaoutar Zeghari ◽  
Hasna Louahlia ◽  
Malo Leguern ◽  
Mohamed Boutouil ◽  
Hamid Gualous ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Behaviour ◽  
Calculation Method ◽  
Building Materials ◽  
Residential Building ◽  
Local Heat ◽  
Energy Performance ◽  
Stationary Regime ◽  
Thermal Regulation ◽  
Climate Data

The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro-thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base .

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