What Is Concrete Thermal Conductivity?
Concrete Thermal Conductivity
Concrete thermal conductivity is a measure of the ability of concrete to transfer heat energy. It is usually expressed in watts per meter Kelvin (W m-1 K-1).
The thermal conductivity of normal concrete is around 2.25 W m-1 K-1, however, it decreases linearly with increasing fractions of glass bubbles, reaching as low as 1.3 W m-1 K-1 in specimen K30.
This decrease in thermal conductivity provides increased insulation and reduces the amount of heat transferred through the concrete.
What Do You Mean By Thermal Conductivity?
Thermal conductivity is a measure of how well heat flows through a material. It is the rate at which thermal energy is transferred from one point to another when there is a temperature gradient perpendicular to the area involved.
Materials with higher thermal conductivity can effectively transfer more heat from the warmer side to the cooler side than materials with low thermal conductivity.
Thermal conductivity is an important factor for many engineering applications where efficient heat transfer must be achieved, such as in building insulation, electronics cooling and nuclear power plants.
Why Is The Thermal Conductivity Of Concrete Important?
The thermal conductivity of concrete is important for energy efficiency in buildings. By using concrete with low thermal conductivity, such as CBA concrete, the heat transfer through the walls can be reduced which results in lower energy consumption.
This means that building structures can remain comfortable while reducing their overall energy usage and thus costs. Thermal conductivity is an important factor to consider when designing any type of building structure since it directly impacts its efficiency.
How Can We Reduce The Thermal Conductivity Of Concrete?
To reduce the thermal conductivity of concrete, increasing the cementitious composite porosity by 1% can prove to be an effective measure.
Studies conducted by Bhattacharjee and Krishnamoorthy have evidenced that such a measure can reduce the thermal conductivity of cementitious composites within a range of 2.42-3.08″.
Additionally, it has been observed that with every 1% increase in porosity, the thermal conductivity is reduced by 0.6%. Thus, implementing such steps will help immensely when trying to reduce the thermal conductivity of concrete.
How Can The Thermal Conductivity Of Concrete Be Increased?
The thermal conductivity of concrete can be increased by incorporating polyamide fibres and metallic particles such as straws into the mix.
This reduces spalling and improves thermal conductivity, in addition to allowing for easier moulding through vibration when using a low water content concrete mix.
Adding these materials to the concrete mixture can significantly increase both strength and thermal conductivity, creating a much more durable material that is better able to withstand changes in temperature without compromising its integrity.
Why Is Concrete A Good Thermal Insulator?
Concrete is an excellent thermal insulator because it is an effective air barrier, preventing drafts that would otherwise cause heat loss.
Although concrete has a relatively low R-value, when combined with foam insulation it can form a highly efficient system capable of regulating the ambient temperature inside a building.
Its durability also makes concrete both cost-effective and long-lasting, ensuring its benefits are felt for years to come.