From what you describe, you have a 2x3 factorial, with replication. That is, you have samples of both chemicals at each of the 3 conditions of standard, water and oven. And you have more than one concrete slab with the same combination of chemical and condition.
Given this, you need to run the Fit Model platform, specifying the Model Effects:
Chemical
Condition
Chemical*Condition(Even though you indicate there is no correlation with the conditions, the inclusion of this interaction effect will allow for the testing of such)
along with your measurement variable as your Y (response) variable.
Full documentation, along with interpretation of the reports displayed in the output can be found in the Fitting Linear Models guide. It is available under the Help pull down menu
Help==>Books==>Fitting Linear Models
Jim