COR-TEN is a tradename used by U.S. Steel for a group of HSLA structural steels.  You can find information on these grades, including mechanical properties, at the following website:

http://www.ussteel.com/corp/Plate/products/usscortn.htm

The coefficient of thermal expansion depends on temperature, and to some extent on alloying content.  The following data is for a C-Mn-Si steel, which is what COR-TEN is:

CTE                     Temperature
(in micrometers/m C)    (in degrees C)

9.5                       25
11.5                     100
13.5                     200
15.0                     300
16.0                     400
16.4                     500
16.6                     600

Note that this data is not averaged.  IF you want an averaged number, then something like the following values would be more appropriate

AVG CTE
10.2   from 20-100 C
13.5   from 20-400 C
14.4   from 20-600 C

As for Rockwool, I am not familiar with this name.  You may try the following website for info:

http://www.rockwool.ltd.uk/web/product-index.cfm

Rockwool is a trade name for a type of mineral fibre insulation made by, would you believe, Rockwool.  Their main site www.rockwool.dk is very comprehensive and should contain most of the info you are looking for.

Regards

Ed

properties of rockwool
thermal properties
and insulation information

regards