Density Testing using modified Proctor when standard is required!
Density Testing using modified Proctor when standard is required!
(OP)
I have a situation. I have been testing for 2-days using a VTM-12 (Virginia Test Method) One Point Proctor values of 104.7 lb/cu.ft @19.2 OMC. The VTM-12 test uses Standard effort.
For 2 days I have passed compaction in a green area requiring 85% of Standard Proctor. My lab tech mistakenly ran a modified Proctor yielding values of 115.3 lb/cu. ft @ 14.9% OMC. Obviously, the previous tests no longer meet the 85% compaction required.
I will have him rerun the test, but in the meantime, can anyone give a general %-comp equivalency for 85% and 95% of Standard Proctor? Soil is a sandy CL with negligable gravel.
TIA
For 2 days I have passed compaction in a green area requiring 85% of Standard Proctor. My lab tech mistakenly ran a modified Proctor yielding values of 115.3 lb/cu. ft @ 14.9% OMC. Obviously, the previous tests no longer meet the 85% compaction required.
I will have him rerun the test, but in the meantime, can anyone give a general %-comp equivalency for 85% and 95% of Standard Proctor? Soil is a sandy CL with negligable gravel.
TIA





RE: Density Testing using modified Proctor when standard is required!
also, if I specify 85% for a yard area, i'm more or less telling the grader to "track it in" since they won't be able to build on it later. i can't see anything bad happening in the future if it were 82's and not 85+'s, unless it should have been specified higher in the first place.
i would double check to see if there might be a higher utility backfill soil specification that may be crossing your green area. They may have to put in utilities and not dig all the way through the yard fill to existing materials.
on another note, i have seen some retaining wall engineers specify 95% Std or 92% Mod. i believe their rational is to keep the design as general as possible to work with site specs thus keeping the phone calls down. In my experience, relation b/n the (Mod Proc/Std Proc) is greater proportionally for clays than silts, or silts than sands, and finally sands than gravels. so, i couldn't give you a rule of thumb.
RE: Density Testing using modified Proctor when standard is required!
RE: Density Testing using modified Proctor when standard is required!
You are not saying your one-point and your maximum dry density are the same point?
If that were the case, you would need to dry back the sample and run your one-point again. One-points must be a little dry (3%-5% is good) of optimum moisture content to give meaningful results to extrapolate a maximum dry density.
RE: Density Testing using modified Proctor when standard is required!
Thx
RE: Density Testing using modified Proctor when standard is required!
the 1st thing i always would check when reviewing density testing was if the one-pt looked legit. just a habit of mine.
I think you'll be fine. Let us know if you get any surprises.
-Cheers,
dsg
RE: Density Testing using modified Proctor when standard is required!
hope this helps. for what it's worth, other very important points have already been addressed.
f-d
¡papá gordo ain’t no madre flaca!
RE: Density Testing using modified Proctor when standard is required!