Construction Inspection for Field Office Activities Earthfill Testing and Quality Assurance Typical testing equipment Documenting Demonstrate some field techniques to determine proper moisture 1

Earthfill Quality Assurance 2 Typical Testing Equipment

3 Dig up a sample deep enough to check bonding between lifts Check moisture by making a ball or rolling out a thread Check compaction by using the thumb test Depth of thumb indention is an indicator of compaction Using a shovel to check moisture and compaction

4 Compaction Rule of Thumb From ASTM D2488

5 Prepare area for testing Drive mold or calibrated cylinder into compacted fill Trim mold and weigh to determine wet density Check compaction by using the thumb test Oven dry to determine moisture and dry density Using a drive mold to check moisture and compaction

11 Very similar to drive mold, but has plastic liner Prepare area for testing Drive sampler into compacted fill Trim and seal for transport to lab Using an undisturbed sampler for permeability tests

17 Prepare area for testing Place gauge, insert rod and start test Retract rod and check results Collect sample for moisture calibration and/or percent gravel Gauge measures wet density and moisture, calculates dry density Using a nuclear gauge to check moisture and compaction

Troxler Moisture/DensityGauge Base of gauge showing source rod exit point. The detector tubes are located in the gauge base above the purple line. Gauge resting on “calibration” block.

Troxler Moisture/DensityGauge Wet density is measured directly based on calibrations at the factory The moisture is measured indirectly based on number of neutrons measured The gauge must be moisture calibrated for each soil type for accurate results

Troxler Moisture/DensityGauge Important accessories include the rod, hammer, and guide template.

23 Most documentation will be by observation of placement methods and simple field tests Take pictures and log observations in Job Diary For additional knowledge on testing, Soil Compaction for Field Control course is available Documenting moisture and compaction meet requirements

Field test for Optimum Moisture – Thread test Try to roll a small pat of soil into a 1/8” thread using a smooth surface. This test works on fine-grained plastic soils. (CL, CH, maybe SC) 24

Field Test for Coarse soils – Hand Test 25 Pick up a handful of soil. Squeeze it in your hand. Open your hand. If the soil is powdery and will not retain the form given by your hand it is too dry. If it shatters when dropped it is too dry. If the soil is moldable by hand and breaks into only a couple of pieces when dropped, it has the right amount of moisture for proper compaction If the soil is plastic in the hand, leaves small traces of moisture on your fingers, and stays in one piece when dropped it has too much moisture.

Field Tests – Using example specifications for GSS 26 Hands on time – Several soil samples and ceramic tiles will be available for the participants to test according to the example specifications. Determine if the sample meets the moisture requirements for hand compacted backfill.

27 Class Exercise Earthwork Problem – Questions 3&4 Using the same earthwork problem again, answer questions #3 & #4

Field Tests Review 28  Field tests can be used to show contractors and others that moisture conditions are suitable for the job  Field tests may be adequate to indicate work does not meet specifications, depending on how they are written

Earthfill QA Review True or False: 1.A shovel can be used to document moisture and density of earthfill. 2.Calibrated drive molds are used to determine wet density of earthfill. 3.Nuclear gauges accurately measure density and percent moisture. 29