R-Value of Concrete/Concrete Block

[minotto Disegno]

Concrete has a R-value of only 0.08 per inch. (8” = .64)

8” concrete block has a R-value of 1.11


It’s essentially the same material, isn’t it? Does anyone know why there is a difference?

 

[jj4091]

Probably because blocks are less dense I would think, but can't give you a definitive answer, might be one for wikipedia.

 

[CambridgeBrummie]

Depends which concrete block you are using and what the actual concrete block is made of (aerated, ggbfs, pfa, etc), its density and compressive strength. eg A Durox Supabloc has a k=0.11W/mK and a Tarmac Hemelite (7N) has a k=0.51W/mK. [R=1/k].