Question
I and a friend built a 100mm path thick of crushed granite, we done 3 stages. first stage we mixed cement and put a little water then compacted w/packer 2nd stage the same 3rd we laid the last course with no cement but we applied a little water before compacting then the crushed granite turned into mud and little holes in the path, then we applied a sprinkle of the crushed granite to fill the holes and what not and compacted again it worked except in some spots it looks like clay

Question? was I meant to compact the last course without applying water to it until its all compacted then wet it and let it settle and not compacted when wet.

thanx Robbie


Answer

terra pave Hello,

The cement content (which should not exceed ten percent) should be mixed throughout the granite and the granite should be slightly moist and not wet when compacted.

If the top layer does not contain cement,the granite in that layer will of course become loose and shear off from the layer below and will become muddy when wet.

The cement and granite should be first mixed in a dry state and then layed down in 1 inch layers which are moistened,not made wet. If the layer becomes wet,wait til it dries to a moist state before compacting.

A wet layer of granite may still achieve the desired hardness when it dries out but sometimes if overwetted binding may not occur.

Decomposed granite containing tree resins as stabilizers (there is a product called terra pave that uses tree resin as the binding agent) are superior than that used with cement. These products appear to retain their hardness much better than decomposed granite with cement as the binding agent. Lime may also be used. You might want to test a small sample of the granite with lime to see what results you get. Use 5 percent lime in the mixture.

In my opinion decomposed granite is not a suitable paving material because it is too tricky to get right and will soften when wet. Its good used as a mulch and as a soil additive but has not proven successful as paving material,at least with cement as a binding agent. DG with resin as the binding agent shows much more promise but even that may not be as permanent as concrete or asphalt. Good luck. Let me know if I can be of further help.

Mark Harshman
http://www.mahdrafting.com
Email: [email protected]

http://www.scribd.com/markscrib47