Aggregate Compaction?
Aggregate Compaction?
(OP)
Hi,
I hope someone can help me out of this. I have an industry site here. Originally, it was spec. as 100mm crushed gravel and 200mm pit-run with 98% SPD compaction. Then the contractor told me if I can reduce 98% SPD to 95% SPD, the compaction cost can drop 40%. So, any thought of that or any resource that I can take a look?
Thanks a lot!
JYF
I hope someone can help me out of this. I have an industry site here. Originally, it was spec. as 100mm crushed gravel and 200mm pit-run with 98% SPD compaction. Then the contractor told me if I can reduce 98% SPD to 95% SPD, the compaction cost can drop 40%. So, any thought of that or any resource that I can take a look?
Thanks a lot!
JYF





RE: Aggregate Compaction?
RE: Aggregate Compaction?
Thank you for your reply.
I couldn't find why they spec. 98% originally and yes, that is a standard proctor density. The crushed gravel and pit-run defines as below
Metric (mm) US Percent Passing
20.000 3/4" 100
16.000 5/8" 84-94
10.000 3/8" 63-86
5.000 #4 40-67
1.250 #16 20-43
0.630 #30 14-34
0.315 #50 9-26
0.160 #100 5-18
0.080 #200 2-10
Metric (mm) US Percent Passing
80.000 3" 100
50.000 2" 44-100
25.000 1" 38-100
16.000 5/8" 32-85
5.000 #4 20-65
0.315 #50 6-30
0.080 #200 2-10
I think that fits your 3" minus portion then. But I don't know how much deferent between 98% or 95%. The majority of traffic loads for the site will be imposed by lightly loaded trucks. But during the construction, 80 tons mobile crane will come in to do the installation.
RE: Aggregate Compaction?
if this will carry construction traffic (light trucks, heavily loaded concrete trucks, or anything else), i'd advise against 95% standard Proctor being your target. you might put to the contractor like this: "you can put it in at 95% standard with the cost savings to the owner and you guarantee the area for x-years". if you tell them it's ok to put it in less than well compacted (i consider 95% standard for base course material to be less than well compacted) and it tears up during construction, someone (the contractor) make "ask" for a sizeable change order to fix it all if they're not on the hook for the end product. that's my experience anyway.
RE: Aggregate Compaction?
RE: Aggregate Compaction?
I agree with Msucog, your original post had 200 mm (8inch), that is why I was questioning doing 98 percent on cobles. For road work you can get 98 percent on base without that much difficulty.
RE: Aggregate Compaction?
cvg,
So, to increase the compaction from 95% spd to 98% spd usually just need one more pass by the roller right? I will ask them about that. I think I need ask some nother contrators for the cost as well.
muuddfun,
sorry for the misunderstanding,that 200mm is the thickness of the pit-run layer, not the size.
RE: Aggregate Compaction?
and i also agree, there's no way they'll cut the costs 40% by simply making a few less passes. the only way i could see it is maybe they leave a bunch of crap in the subgrade whereby it reduces the amount of undercutting/replacement needed to obtain a stable subgrade.
RE: Aggregate Compaction?
RE: Aggregate Compaction?
RE: Aggregate Compaction?