Determination of Thermal Parameters of Concrete by Active Thermographic Measurements

Rainer Krankenhagen,Florian Jonietz,Stefan Zirker

doi:10.1007/s10921-022-00861-6

Rainer Krankenhagen, Florian Jonietz + Show 1 more

Open Access

https://doi.org/10.1007/s10921-022-00861-6

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Abstract

The knowledge of the thermal parameters of a particular concrete is essential for thermal design of a building, but also could help to identify and assess the state of a concrete structure. Active thermography has the potential to be applied onsite and to provide a fast investigation of thermal properties. In this work, three different concrete samples were investigated by active thermography in reflection and in transmission setup. It was found that this method yields the same results without direct contact as the Transient Plane Source (TPS) method as an established inspection tool.

Highlights

Many new materials are being developed and introduced for the construction of buildings, as they offer great potentials for saving energy by e.g., reduced thermal conductivity, concrete is still one of the most widely used materials in the construction industry
One example is the hot disc method or Transient Plane Source (TPS) method, which will serve as a reference method for our measurements [9–12]
Other methods described in the literature include photothermal deflection technique [8], laser spot heating combined with pyrometer point measurements [13], photopyroelectric calorimetry (PPE) [6], time-modulated laser spot heating combined with lock-in thermography [6] or a hotwire technique [14]

Summary

Introduction

Many new materials are being developed and introduced for the construction of buildings, as they offer great potentials for saving energy by e.g., reduced thermal conductivity, concrete is still one of the most widely used materials in the construction industry. The mechanical properties are decisive, and the thermal parameters like heat capacity and thermal conductivity Often, these are not listed in sufficient detail for the used concrete, as the material mixtures might vary gradually. A series of recent studies and publications was focused on the determination of the thermal properties of an entire wall as part of an existing building to evaluate the heat energy consumption [1–3]. The authors of this contribution want to establish a fast method to identify the kind of Several methods exist to determine the thermal properties of materials and in particular of concrete [6, 8]. Santhosh et al used it to determine the porosity in ceramics [19] Most of these methods are laboratory measurements, for which a sample with strong restrictions in size and dimension must be taken

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