Dataset described herein belong to chapter 3: Engineered Granular Materials for Heat Conduction and Load Transfer in Energy Geo-Technology.
As part of a PhD thesis: Physical Properties of Geomaterials with Relevance to Thermal Energy Geo-systems
By Shahrzad Roshankhah
May 2015
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This readme file describes the data excel file named:
Roshankhah-2015-Physical Properties of Geomaterials-CH3- Mass Density & Thermal Conductivity vs. Stress
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This file contains only one sheet of processed data for the evolution of thermal conductivity and mass density of following 7 various dry granular materials under variable vertical stress:
 Glass Microspheres,
 Ceramic Microspheres, 
 Diatomaceous Earth, 
 Fly Ash, 
 Silica Sand, 
 Copper Coated Silica Sand, 
 Nickel Coated Silica Sand
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No acronym/abbreviation has been used. 
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All parameters have been shown in columns by their full title and SI units including:
Thermal conductivity k [W.m-1.K-1]
Stress σ’ [kPa]
Mass Density ρ [kg.m-3]
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Settlement gauge resolution: 0.001”
Temperature gauge (Thermocouple type E) resolution: 0.01 ˚C
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Experiments were conducted at room temperature under variable vertical effective stress and zero lateral strain.
Agilent datalogger 34970A was used to record the temperature evolution over time by the built in thermocouple inside the thermal needle probe during mechanical vertical loading and unloading. 
A short (3 minutes) heat pulse (3 V) was imposed at every stress level by a DC power supply E3630A to the heating wire located at the center of the thermal needle probe.
Agilent datalogger 34970A was used to record the settlement of specimen by means of voltage difference created in the LVDT.
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Dada reduction for thermal conductivity k [W.m-1.K-1] has been done using the slope of the linear part of temperature T [˚C] vs. logarithm of time log(t/1[s]) and the imposed power per unit length of heating wire Q=VI/L [W.m-1] based on the following equation:
k=Q/4π  (log⁡(t_2⁄t_1 ))/(T_2-T_1 )
Data reduction for mass density ρ [kg.m-3] has been done by measuring the settlement of the specimen δ [m], specimen mass m [kg], specimen initial height Ho [m], specimen diameter D [m]:
ρ=m/(π/4 D^2 (H_o-δ) )
 A linear model was proposed for the variation of the mass density versus stress as follows:
ρ=ρ_1 [1+χ log⁡(σ^'/1kPa)]
Where, ρ1 [kg.m-3] is the mass density at 1 kPa and χ is the increase in mass density per 10-fold increase in stress.
A linear model was proposed for the variation of the thermal conductivity versus stress as follows:
k=k_1 [1+β log⁡(σ^'/1kPa)]
Where, k1 [W.m-1.K-1] is the thermal conductivity at 1 kPa and β is the increase in thermal conductivity per 10-fold increase in stress.
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The thermal needle probe used to measure the thermal conductivity was calibrated by a stabilized water specimen at the room temperature based on ASTM Standard 5334, 2008 (kw = 0.6 W.m-1.K-1).
The LVDT used to measure the settlement of the specimen was calibrated by a Nike precise x-y coordinate.
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Microsoft excel was used to analyze the data.