Building Materials

This case highlights research into more insulative building materials by mixing aerogels with cement for better thermal performance. Aerogel is an extremely insulative material with a stated value of less than 0.03 W/mK in pure form.

Thermal conductivity results of the mixed samples tested with the TCi are shown in the graph below. Increasing weight % of aerogel content directly related to a reduction in thermal conductivity of the cured cement composite. Treating of 2.0 weight % aerogel saw a thermal conductivity decrease of over 75%.

The thermal conductivity of a light-weight concrete was measured utilizing the C-Therm Transient Plane Source (TPS) FLEX sensor.

The flexible, 13mm Kapton-based sensor was placed between a sliced lightweight concrete cylinder. 

Referencing ISO standard documents and an approximation of the thermal conductivity, the power applied was chosen to be 0.5W and the measured test time to be 40s. Experiments were carried out in 10 trial segments.

Following ten measurements with removal of the sensor between tests, the thermal conductivity of the lightweight concrete was determined to be 0.52 W/mK with a reproducibility better than 5%. 

Figure 1. illustrates the reproducibility results, with the average thermal conductivity of the 10 trials represented by the solid line. Above and below the average line are +/- 5% error lines. The observed variation between tests can be partially attributed to the sample’s inhomogeneity.

The precision was also examined via an additional 10 measurements without the removal of the sensor between measurements. A 3 minute wait time between measurements ensured the heat completely dissipated prior to the next measurement. The precision was determined to have a better than 2% relative standard deviation.