Evaluation Of Thermal Properties Of Cement-Exfoliated Vermiculite Blocks As Energy Efficient Building Envelope Material

Keywords

Compressive strength; Exfoliated vermiculite; Thermal conductivity; Thermal damping; Thermal performance index

Abstract

Lightweight exfoliated vermiculite (EV) aggregate particles were mixed with cement-mortar to form exclusive cement-EV specimens of 1:0.5, 1:1, and 1:1.5 wt. % proportions, respectively. The thermal conductivity of these specimens was determined using a fabricated experimental setup, wherein the top and the bottom surface temperatures of the specimen were measured with respect to the heat flux within a specific time interval. Properties such as thermal resistivity, thermal transmittance, thermal performance index (TPI), and thermal damping are investigated using empirical relations and compared to that of the conventional cement-mortar specimen. The compressive strength was determined in accordance with the ASTM C31 standards for 7 and 28 days of curing. From the results, it was identified that the compressive strength of cement-EV 1:1 was 13.5 % less than cement-EV 1:0.5. The strength of cement-EV 1:1.5 was observed as 72 % and 51 % less than that of cement-EV 1:0.5 and 1:1, respectively. This is due to the increase in the porosity of the specimen. A significant reduction was noticed in the thermal conductivity of cement-EV 1:1.5 value (0.189 W/mK), with an increased value of resistivity (5.29 mK/W) when compared to that of the cement-mortar specimen. The TPI of the cement-EV 1:1.5 was reduced to 57 % less than the TPI of the cement-mortar, with an indication of the higher thermal stability of the material. Similarly, the results also showed an increase of 56 % and 71 % damping values for cement-EV 1:1 and 1:1.5, respectively. Hence, cement-EV proportions provide satisfactory strength and thermal properties for its usage as a lightweight building envelope in residential constructions, with higher thermal resistance and stability against fluctuating external temperature ranges.

Publication Date

9-1-2019

Publication Title

Journal of Testing and Evaluation

Volume

47

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1520/JTE20170520

Socpus ID

85058702931 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85058702931

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