reporting compaction test results 1

[boffintech]

ASTM 2937-04 states NOTE 2—It may be desired to express the in-place density as a percentage of some other density, for example, the laboratory maximum density, determined in accordance with Test Method D 698. This relation can be determined by dividing the in-place density by the maximum density and multiplying by 100.

The question is to what accuracy is the resulting comparison reported to? I have always been taught to round off to the nearest whole number for % compaction. Others argue to report to nearest 10th for % compaction.

 

[DRC1]

Report to the lowest level of prescion of the two numbers.

 

[GeoPaveTraffic]

I would never report test results to more than 0.5 pcf and percentages to more than the nearest whole number. Any more would be giving a false since of accuracy.

 

[Ron]

I agree with GPT...nearest whole number for percent compaction; however, I believe ASTM requires reporting unit weights to nearest 0.1 pcf.

 

[TDAA]

My thought is that you should report what you get. If the testing is sand cone or drive cylinder, report to the correct significant digits. Itf it is a nuclear gage test, report what the gage tells you, normally the 10th.

Then know in your mind that there is variability: how well things were measured, and the know variation of the gauge (varies based on length of test, surface prep, etc.)

If you repoert exactly what shows on the screen, then you do not add additional variation based on your rounding.