International research results on the thermal conductivity of concrete

Introduction

This is the last part of the small series of articles on the thermal conductivity of concrete exposed to fire. The results of some international research work are summarized below and conclusions drawn from them. The article is based on the basics in the first part of the article series. If you are also interested in the results of national research, I recommend reading the second part of the series of articles.

Thermal conductivity of concrete at room temperature

Research of Tara L. Cavalline, Reid W. Castrodale, Charles Freeman and Jody Wall

The authors Cavalline el al. investigate in their publication "Impact of Lightweight Aggregate on Concrete Thermal Properties" (ACI Materials Journal, November-December 2017), among other things, the influence of lightweight aggregates on the thermal conductivity of concrete. The authors carried out the investigations exclusively at room temperature. The authors came to the following key conclusions:

• Lightweight aggregates affect the thermal conductivity of concrete more than increased cement content.
• The higher the density of a concrete, the higher its thermal conductivity.
• The higher the air void content, the lower the thermal conductivity.

Thermal conductivity of concrete in case of fire

Release of I.R. Upasiri et al.

The team of authors around Upasiri et al. summarizes in her 2018 publication "Review on Fire Performance of Cellular Lightweight Concrete" summarizes the state of research on lightweight concrete exposed to fire. The authors state, among other things, that:

• There are isolated international studies on the thermal conductivity of lightweight concrete up to approx. 600°C.
• There are no comprehensive studies on the thermal conductivity of lightweight concrete in the temperature range of approx. 600°C. up to approx. 1200°C.
• So there is a need for research here, because fires definitely reach temperatures in the range of 1200°C and higher.