Determination of thermal conductivity of backfill

Shallow foundations with thermal insulation can be used in the construction of low-rise buildings. Thermal insulation prevents freezing of soils under the foundation. The article presents the results of determining the thermal conductivity of sand with the addition of crushed brick and concrete rubb...

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Bibliographic Details
Published in:IOP conference series. Materials Science and Engineering 2020-10, Vol.945 (1), p.12071
Main Authors: Churkin, S V, Korshunov, A A
Format: Article
Language:English
Subjects:
Construction materials
Crushing
Freezing
Heat conductivity
Heat transfer
Heat transmission
Laboratories
Laboratory tests
Low rise buildings
Mathematical models
Sand
Shallow foundations
Soil testing
Temperature sensors
Test chambers
Test procedures
Thermal conductivity
Thermal insulation
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Summary:Shallow foundations with thermal insulation can be used in the construction of low-rise buildings. Thermal insulation prevents freezing of soils under the foundation. The article presents the results of determining the thermal conductivity of sand with the addition of crushed brick and concrete rubble. The research was carried out in a specially designed unit, which consists of two climatic chambers connected to each other. The soil sample is maintained into the special cell. Heat flow and temperature sensors are placed in the soil sample. Before soil testing a numerical simulation of laboratory test was implemented in GeoStudio. Due to numerical modelling optimal dimensions of testing cell was defined. Results of laboratory testing of sand with a known thermal conductivity with using designed parameters of cell has a good agreement with calculated value. The test procedure was extended to soils with construction waste. The addition of 20% crushed brick to the sand reduces its thermal conductivity coefficient by 20.6% in the frozen state and by 10.1% in the thawed state. At the same time sand with concrete rubble showed a decrease in the thermal conductivity coefficient in the frozen state by 6.4% and an increase by 13.4% in thaw. The effect is occurred because of the addition of particles of different mineralogical composition with different thermal conductivity. The results of testing can be used in making forecast of the thermal regime of soil stratum when designing shallow foundations.
ISSN:1757-8981
1757-899X
DOI:10.1088/1757-899X/945/1/012071