Tassanai Boonkerdrattanasakull, Naris Pratinthong, and Nath Kasayapanand

pp. 391 - 399

Abstract

The objective of this research work was to develop a thin film thermal conductivity probe for measuring thermal property of construction materials. This probe was developed based on the line heat source principle. The thermal conductivity can be determined from the slope of linear relation between the temperature differences ∆T and logarithm of time ln(t). The probe was tested by measuring the thermal conductivity of three kinds of specimens comprising of polystyrene foam (PS), autoclaved aerated concrete (ACC) and gypsum board (GB) The range of electrical power supply rate for the probe was varied from 0.15 to 1.59 W. The thermal conductivity values obtained with this method were greater compared to the results obtained using the ASTM C 177. The difference of thermal conductivity between line two methods decreased with the increase of the power supply rate. The mean difference for PS, ACC and GB was 4.33%, 6.15% and 42.34% respectively. According to the restriction of minimum thickness requirement of specimen for testing with the guard hot plate apparatus (ASTM C 177), it was necessary to overlay one GB slab on another. As a
result, the mean difference of thermal conductivity for GB was considerably high.