What does it mean by 95% compaction?

What does it mean by 95% compaction?

There are two compaction tests I am familiar with, standard Procter and the modified Procter. These tests are preformed in a lab on bulk soil samples that are being considered to be used as fill material. The test gives the engineer a baseline of how the optimal moisture content and achievable density for a specific compaction effort.

95% compaction means that the soil on the construction site has been compacted to 95% of the maximum density achieved in the lab. Remember the test in the lab uses a specific compaction effort so it is possible to achieve compaction above 100% in the field. I have seen airstrip plans that specified 105% compaction of a modified Marshal Proctor.

It means that when you conduct compaction test(in the laboratory) on a small soil sample of a particular site. You get some value of maximum dry unit weight at certain moisture content. Lets assume that maximum dry unit weight that you obtained is “D”.