gravel driveway: concrete crush underneath type1?

[ash_h]

Hi,

I have a question that I hope someone can help with their expertise.

I'm having a gravel driveway installed tot he front of my house. The area before was partly block paved but mostly grass.

The agreed spec was to dig out 200mm, lay a geotextile membrane and then 150mm type 1 (compacted), finishing and 50mm gravel.

The chap installing the driveway showed me a few soft spots during the digging out, but before they had dug to the correct depth. The digging out is now finished and they are now laying "concrete crush" (around 100mm - 150mm concrete bits) on to the geotextile membrane (will be rolled in), and will then lay 50mm type 1 (again compacted).

Is this correct? Is it stronger than the original spec?

Thanks

 

[ETAF]

if the spec was for 200mm (8'') and they have only now gone down 100mm (4") then they have not really completed to the spec that you agreed, I would discuss with the builder.
i'm not sure about the strength , but you agreed to 200mm . and assume paid for the labour to dig out and the ballast to fill
I had a similar issue with new soak away, the builder who specced it, he did not come on site and the contract guys who fitted did what they could get away with, i made them dig it all up and start again and do the job as agreed, which they did , including relaying grass they had destroyed, and then they went into liquidation after i had paid them, as the turf had issues and was not growing over the soakaway - so i could not get them back to sort out

 

[phatboy]

If the crushed concrete meets the spec of type 1 (40mm and down) then it really is type 1 surely?!

Same difference.......

 

[ash_h]

it doesn't - that's the point. It's 100mm- 150mm concrete lumps

 

[Notch7]

it doesn't - that's the point. It's 100mm- 150mm concrete lumps

Thats not graded concrete crush, its broken hardcore and unsuitable.

A sub base needs to be graded aggregate from around 40mm down to zero,

Your big lumps wont lock together as its compacted and will have too many voids.

When buying by the lorry load there isnt a massive cost difference between concrete crush and type 1

 

[ash_h]

thanks Notch7

 

[phatboy]

it doesn't - that's the point. It's 100mm- 150mm concrete lumps

My bad, mis-read that as being the depth, not the grade! Sorry....