Journal Published Online: 24 September 2018
Volume 47, Issue 5

Evaluation of Thermal Properties of Cement-Exfoliated Vermiculite Blocks as Energy Efficient Building Envelope Material



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.

Author Information

Innocent, Lovelyn Theresa
Buildings Research Division, Florida Solar Energy Center, Guindy, Chennai, FL, USA
Ramalingam, Velraj
Department of Mechanical Engineering, Institute for Energy Studies, Anna University, Guindy, Chennai, India
Pages: 16
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Stock #: JTE20170520
ISSN: 0090-3973
DOI: 10.1520/JTE20170520