Awarded as the best online publication by CIDC

Do soil compaction test results over 100% mean over-compaction?

Soils can experience over-compaction if the compactor makes too many passes over it. In fact, relative soil compaction test results over 100% do not necessarily mean over-compaction because the relative compaction is based on the maximum dry density of the soil obtained by the Proctor test and this does not necessarily refer to absolute maximum dry density.


Over-compaction is considered undesirable because it may eventually create cracks in the underlying compacted material so that it results in a decrease in density. Moreover, it causes waste of machine power and manpower which is undesirable.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

Share this post

Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

If you have a query, you can ask a question here.

8 comments on "Do soil compaction test results over 100% mean over-compaction?"

julius ogowewo says:

in asphalt in-situ density tests, if % relative compaction is less than 100%, should engineers accept the results. what is the solution or remedies.

V Nguyen says:

In-situ Asphalt tests are compared to a MRD or BRD (Maximum Relative Density/Bulk Relative Density) and where I live the values would range from 92%-97% (Canada, ON) being acceptable limits, but limits may vary due to city standards. The asphalt would crack at 100% compaction as asphalt requires adequate void spaces due to the environmental/human influences (frost heaving, large trucks, etc.).

Pramod J says:

What is the maximum acceptable limit of compaction above 100% as per the standards?

Mirwais says:

In our project Construction Specification degree of compaction that is at least 100 percent of laboratory
maximum density through the full depth of the layer, What is the maximum acceptable limit of compaction above 100% as per the standards for base course?

Derek says:

I think the question is basically, at what point over 100% is it not acceptable. FDOT requires a new proctor on anything over 105%
I personally would like to know if ASTM has a cut off point.

Derek says:

Sorry I was referring to soils. … 100% is to much for asphalt.

Terry Stanley says:

On the average, how long would you expect a subgrade compaction to remain acceptable?

Heath says:

Sorry but you are wrong anytime you test for compaction under asphalt if you’re testing compaction on any ADOT job asphalt has to be 100% compaction that’s the only thing acceptable can’t be 99 98 97 has to be 100%. If you’ve ever done any testing for ADOT you would know this all asphalt 100%

Leave a Reply

Your email address will not be published. Required fields are marked *

Ask a question