What is the effect of changing stabilised base course layer(C2) to cru

[defg]

Due to shortage of appropriate materials which comforms to C2 requirements prior to stabilisation,I was obliqued to request for a change.Instead of using stabilised base of 150mmthick to use 150mm thick of crushed stone base.Granite rocks are plenty in the project area.The design traffic class in this project area is TCL-10(3-10)E80millions.The Client insisted that change should be accompanied with thick layers of crushed stone(CRR)materials.Instead of using 150mm thick to be 200mmthick.And laying the base course materials to be into two operations,means first layer to be 100mmthick compacted then to be followed with another layer of 100mmthick.Means total to be 200mmthick of crushed stone base.Is it appropriate method of construction?

 

[Ron]

You've used a lot of apparently local or regional jargon in your requirements, so I'm not familiar with that; however, I'm guessing that your traffic requirements are moderate. Given that, a 200mm base course is reasonable. As for the granite, if it is "crusher run", meaning it is crushed and only scalped on the top size stone, it will create a stable base material when compacted.

Placing the base course in two 100mm layers is a good idea, provided your top size of material doesn't exceed 40mm to 50mm. If you have material that will exceed 50mm, then it is better to place in thicker lifts because the larger material tends to "punch" into the layer and loosen during compaction.