SUPERPAVE Digest 133

SUPERPAVE Digest 133

Topics covered in this issue include:

1) VMA Specifications in Maine

2) Re: VMA Specifications in Maine

3) VMA Specifications in Maine

by <>

I am currently working on QC/QA/Superpave specs with a task group. We are

debating the proper limits to set for VMA. There is a desire to set a high

limit as well as a low limit and to use VMA as a price adjustment property.

I contend that the SHRP Table values are somewhat higher than they should be

and we should set the LSL to 1 % below JMF aim. I also think a reasonable

range would be +/- 1.5%.

I would appreciate comments from other states/state agencies on how they are

handling this issue.

I would recommend using limits the way you did before superpave. If you had

an upper limit then use an upper limit with superpave.

These are our vma limits at OKDOT.

Nominal Max. Aggregate Size

37.5mm 25mm 19mm 12.5mm 9.5mm

VMA %Min. 11 12 13 14 15

(SSD bulk specific gravity of the aggregate)

In NE we specify the SHRP VMA values as the Minimum. I feel we will

end up with a spec that says if the moving average of 3 or 4 tests is

below this minimum production will stop and aggregate adjustments will be

made to get the VMA above that minimum. Single tests below some value,

yet to be determined, are investigated further. We have never seen VMA

values going too high. I tend to believe the Superpave VMA values are OK

for the higher traffic levels, but somewhat low for lower traffic levels.

NE defines only 4.0% air voids as a JMF aim. Values such as VMA,FAA,

VFA, Density are just minimums or ranges and test results must be above

or within. A 4.0% target for air voids is a must but for the other tests

I see no need to tie them to target values.

SUPERPAVE Digest 134

Topics covered in this issue include:

1) Re: VMA Specifications in Maine

by Douglas Coleman <>

I believe other questions need to be ask before you can get the right

answer. Are limits placed on % AC and Air Voids, if so The VMA limits

should be compatable with these limits. I believe a Mim. VMA spec. should

set for the Design, the JMF and controller the field mixture with Voids, AC

and VMA. Voids are a Target of 4% =/-0.5%, AC is a target =/- 0.3%, and VMA

is the JMF limit.