The micro-cellular structure of Thermalite® gives the material protection against the effects of frost.
Independent comparative frost resistance tests have been carried out on facing bricks, common bricks and Thermalite® blocks. After 20 freeze/thaw cycles, the facing bricks were severely cracked. At 61 cycles, the Thermalite® blocks showed no signs of cracking.
This test was repeated with additional strength tests being carried out after 20, 40 and 60 cycles, and this confirmed that Thermalite® has satisfactory frost resistance and that there is no reduction in strength under these conditions.
| |
0 cycles |
20 cycles |
40 cycles |
60 cycles |
| Saturated cube strength (N/mm²) |
4.67 |
4.94 |
5.37 |
5.45 |
| Change on original |
Nil |
+15% |
+15% |
+16% |
A similar test undertaken by the British Board of Agrément (BBA) produced similar results:
| Nominal density(kg/m³) |
As received |
After 60 cycles freeze/thaw |
Increase |
| 500 |
3.20 |
3.25 |
+1% |
| 600 |
3.85 |
4.10 |
+6% |
| 730 |
5.80 |
6.00 |
+3% |
The inherent frost resistance of Thermalite® blocks means that all products within the range are suited for use below d.p.c level. The data shown is confirmed by laboratory tests carried out to draft European Test Methods (undergoing development at time of writing). The mortar properties should be appropriate to the degree of frost resistance required.