Paving blocks for road shoulders.

[defg]

What is the required compressive strength for the paving blocks design for road shoulders?I'm currently making some paving blocks for road shoulders having the following dimmensions(220mmx110mmx70mm thick).These blocks when crushed they yeild compressive strenth of around (7 to 9)MPa.
In the specification nothing has been given reguarding the stregth requirements for the paved blocks.If there is any one know the reference book,please assist.

 

[Ron]

For concrete pavers, your compressive strength is way below what should be expected. Most concrete pavers are going to have strengths of 50 MPa or greater.