Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures

Structural lightweight concrete (LWC) has recently acquired research importance because of its good thermal insulation properties. However, there is a lack of knowledge about its thermal properties at elevated temperatures. The thermal properties, such as thermal conductivity and specific heat, of p...

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Autores principales:	Juan Enrique Martínez-Martínez, Felipe Pedro Álvarez Rabanal, Mariano Lázaro, Mar Alonso-Martínez, Daniel Alvear, Juan José del Coz-Díaz
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	lightweight concrete thermal conductivity specific heat elevated temperatures Technology T Engineering (General). Civil engineering (General) TA1-2040 Biology (General) QH301-705.5 Physics QC1-999 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/006aa8bc93dd4d26865eff02a79edec3
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spelling	oai:doaj.org-article:006aa8bc93dd4d26865eff02a79edec32021-11-11T15:06:15ZAssessment of Lightweight Concrete Thermal Properties at Elevated Temperatures10.3390/app1121100232076-3417https://doaj.org/article/006aa8bc93dd4d26865eff02a79edec32021-10-01T00:00:00Zhttps://www.mdpi.com/2076-3417/11/21/10023https://doaj.org/toc/2076-3417Structural lightweight concrete (LWC) has recently acquired research importance because of its good thermal insulation properties. However, there is a lack of knowledge about its thermal properties at elevated temperatures. The thermal properties, such as thermal conductivity and specific heat, of porous LWC vary depending on the aggregates, air voids, and moisture content of the LWC in question. To study these effects, in this paper, we measured the thermal properties of three types of structural LWCs at different temperatures, combining different characterization techniques, namely, differential scanning calorimetry (DSC), laser flash analysis (LFA), and modified transient plane source (MTPS). Bulk density and porosity were also evaluated. Specific heat is analyzed by the DSC technique from 20 to 1000 °C and the MTPS technique from 20 to 160 °C. Thermal conductivity is studied using MTPS and LFA techniques at temperatures ranging from 20 to 160 °C and 100 to 300 °C, respectively. The results indicate that the thermal properties of LWC are highly affected by moisture content, temperature, and porosity. For LWC, the current Eurocodes 2 and 4 assume a constant value of specific heat (840 J/kg°C). This research reveals variability in temperatures near 150, 450, and 850 °C due to endothermic reactions. Furthermore, for low temperatures, the higher the porosity, the higher the thermal conductivity, while, at high temperatures, the higher the porosity, the lower the thermal conductivity. Thus, Eurocodes 2 and 4 should be updated accordingly. This research contributes to a deeper understanding and more accurate prediction of LWC’s effects on thermal properties at elevated temperatures.Juan Enrique Martínez-MartínezFelipe Pedro Álvarez RabanalMariano LázaroMar Alonso-MartínezDaniel AlvearJuan José del Coz-DíazMDPI AGarticlelightweight concretethermal conductivityspecific heatelevated temperaturesTechnologyTEngineering (General). Civil engineering (General)TA1-2040Biology (General)QH301-705.5PhysicsQC1-999ChemistryQD1-999ENApplied Sciences, Vol 11, Iss 10023, p 10023 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	lightweight concrete thermal conductivity specific heat elevated temperatures Technology T Engineering (General). Civil engineering (General) TA1-2040 Biology (General) QH301-705.5 Physics QC1-999 Chemistry QD1-999
spellingShingle	lightweight concrete thermal conductivity specific heat elevated temperatures Technology T Engineering (General). Civil engineering (General) TA1-2040 Biology (General) QH301-705.5 Physics QC1-999 Chemistry QD1-999 Juan Enrique Martínez-Martínez Felipe Pedro Álvarez Rabanal Mariano Lázaro Mar Alonso-Martínez Daniel Alvear Juan José del Coz-Díaz Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures
description	Structural lightweight concrete (LWC) has recently acquired research importance because of its good thermal insulation properties. However, there is a lack of knowledge about its thermal properties at elevated temperatures. The thermal properties, such as thermal conductivity and specific heat, of porous LWC vary depending on the aggregates, air voids, and moisture content of the LWC in question. To study these effects, in this paper, we measured the thermal properties of three types of structural LWCs at different temperatures, combining different characterization techniques, namely, differential scanning calorimetry (DSC), laser flash analysis (LFA), and modified transient plane source (MTPS). Bulk density and porosity were also evaluated. Specific heat is analyzed by the DSC technique from 20 to 1000 °C and the MTPS technique from 20 to 160 °C. Thermal conductivity is studied using MTPS and LFA techniques at temperatures ranging from 20 to 160 °C and 100 to 300 °C, respectively. The results indicate that the thermal properties of LWC are highly affected by moisture content, temperature, and porosity. For LWC, the current Eurocodes 2 and 4 assume a constant value of specific heat (840 J/kg°C). This research reveals variability in temperatures near 150, 450, and 850 °C due to endothermic reactions. Furthermore, for low temperatures, the higher the porosity, the higher the thermal conductivity, while, at high temperatures, the higher the porosity, the lower the thermal conductivity. Thus, Eurocodes 2 and 4 should be updated accordingly. This research contributes to a deeper understanding and more accurate prediction of LWC’s effects on thermal properties at elevated temperatures.
format	article
author	Juan Enrique Martínez-Martínez Felipe Pedro Álvarez Rabanal Mariano Lázaro Mar Alonso-Martínez Daniel Alvear Juan José del Coz-Díaz
author_facet	Juan Enrique Martínez-Martínez Felipe Pedro Álvarez Rabanal Mariano Lázaro Mar Alonso-Martínez Daniel Alvear Juan José del Coz-Díaz
author_sort	Juan Enrique Martínez-Martínez
title	Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures
title_short	Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures
title_full	Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures
title_fullStr	Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures
title_full_unstemmed	Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures
title_sort	assessment of lightweight concrete thermal properties at elevated temperatures
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/006aa8bc93dd4d26865eff02a79edec3
work_keys_str_mv	AT juanenriquemartinezmartinez assessmentoflightweightconcretethermalpropertiesatelevatedtemperatures AT felipepedroalvarezrabanal assessmentoflightweightconcretethermalpropertiesatelevatedtemperatures AT marianolazaro assessmentoflightweightconcretethermalpropertiesatelevatedtemperatures AT maralonsomartinez assessmentoflightweightconcretethermalpropertiesatelevatedtemperatures AT danielalvear assessmentoflightweightconcretethermalpropertiesatelevatedtemperatures AT juanjosedelcozdiaz assessmentoflightweightconcretethermalpropertiesatelevatedtemperatures
_version_	1718437095381401600

Assessment of Lightweight Concrete Thermal Properties at Elevated Temperatures

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