Study guide
9.1 Field Sample to Report Workflow
ACI Concrete Field Testing Technician Grade I Study Guide Exam
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1 Orientation: Certification Requirements, Written Exam, Performance Exam, and Study Sources
1.1 Credential Purpose and Official Definition 1.2 Eligibility and the Two-Part Certification Path 1.3 Written Exam Format and Dual Passing Rule 1.4 Performance Exam Format and Grading 1.5 Current Study Sources and CP-1 41st Edition 1.6 Validity, Recertification, and Myth Control
2 JTA, Performance Checklists, Common Fail Points, and Field Mindset
2.1 JTA as the Exam Blueprint 2.2 Written Knowledge Versus Performance Skill 2.3 Performance Checklists and the Six Demonstrations 2.4 Timing, Sequence, and Verbal Description Discipline 2.5 Common Fail Points and Result Recording 2.6 Field Mindset, Exam Habits, and Second Trials
3 ASTM C172: Sampling Fresh Concrete and Field Sample Control
3.1 Representative Sampling Purpose and Exam Role 3.2 Sampling Locations and Middle-Discharge Control 3.3 Composite Sample Timing, Remixing, and Protection 3.4 Sample Size, Large Aggregate, and Wet Sieving 3.5 Sequence With Slump, Temperature, Air, Density, and Specimens 3.6 Performance Exam Verbal Description and Field Habits
4 ASTM C1064 Temperature and ASTM C143 Slump
4.1 ASTM C1064 Purpose, Equipment, and Timing 4.2 Sensor Placement, Stabilization, and Reporting 4.3 Temperature Field Errors and Performance Habits 4.4 ASTM C143 Scope, Equipment, and Setup 4.5 Filling, Rodding, Lifting, and Measuring Slump 4.6 Invalid Slump Results, Reporting, and Integrated Habits
5 ASTM C138: Density, Unit Weight, Yield, and Gravimetric Air
5.1 Purpose, Equipment, and the Calibrated Measure 5.2 Sampling, Filling, and Consolidation Choice 5.3 Strike-Off, Cleaning, Mass, and Density 5.4 Yield, Relative Yield, and Batch Comparison 5.5 Gravimetric Air and Theoretical Density 5.6 Reporting, Validity, and Calculation Traps
6 ASTM C231: Pressure Air Method, Type B Meter, and Aggregate Correction
6.1 Scope, Principle, and When Pressure Air Fits 6.2 Type B Meter Equipment, Calibration, and Setup 6.3 Sampling, Bowl Filling, Consolidation, and Strike-Off 6.4 Type B Sequence: Water, Petcocks, Pressure, and Reading 6.5 Aggregate Correction Factor and Final Air Content 6.6 Reporting, Validity, and Invalid-Result Traps
7 ASTM C173: Volumetric Air Method, Rollameter, Alcohol Correction, and Validity
7.1 Scope, Equipment, and When the Volumetric Method Fits 7.2 Sample, Bowl Filling, Consolidation, and Strike-Off 7.3 Water, Alcohol, Initial Liquid Level, and Sealing 7.4 Inversion, Shaking, Rolling, and Air Release 7.5 Reading Agreement, Out-of-Range Steps, and Invalid Results 7.6 Alcohol Correction, Calculation, Reporting, and Performance Habits
8 ASTM C31: Making and Curing Cylinders and Beams, Initial Curing, and Transport
8.1 Purpose, Sample, Equipment, and Specimen Plan 8.2 Cylinder Molding, Consolidation, Finishing, and Identification 8.3 Beam Molding, Flexural Specimens, and Finishing 8.4 Initial Curing, Protection, Temperature, and Moisture 8.5 Standard Curing, Field Curing, Final Curing, and Interpretation 8.6 Transport, Lab Handoff, Reporting, and Common Failures
9 Integrated Field Workflow: Test Order, Documentation, and Quality Control
9.1 Field Sample to Report Workflow 9.2 Test Order and Parallel Timing 9.3 Documentation and Report Accuracy 9.4 Invalid Results and Retest Decisions 9.5 QA/QC Communication and Acceptance Context 9.6 Contamination, Delays, and Handoff Control
10 Written Exam Strategy: Numerical Values, Calculations, and Category Scoring
10.1 One-Hour Written Exam Pacing 10.2 Category Scoring and the No-Compensation Rule 10.3 High-Yield Numerical Values and Units 10.4 Density, Yield, and Gravimetric Air Calculations 10.5 Air Content Corrections and Validity Checks 10.6 Method-by-Method Practice Plan
11 Performance Exam Strategy: Equipment Setup, Examiner Communication, and Remediation
11.1 Performance Exam Map and Mindset 11.2 Equipment Setup, Station Control, and Safety 11.3 Examiner Communication and Speaking the Work 11.4 One-Step Errors, Timing, and Method Control 11.5 C172 Verbal Description Under Pressure 11.6 Remediation, Retest Planning, and Field Confidence
12 Final Review: Recertification, Career Paths, and Next ACI Credentials
12.1 Two-to-Six Week Final Review Plan 12.2 Final Week and Test-Day Checklist 12.3 CP-1, JTA, and Source Control 12.4 Recertification, Five-Year Cycle, and Re-Exam Requirement 12.5 Career Paths After Field Testing Grade I 12.6 Next ACI Credentials and Growth Map
9.1 Field Sample to Report Workflow
Key Takeaways Explain This Topic AI
A composite sample under ASTM C172 must be remixed, then temperature, slump, and air begin within 5 minutes of obtaining the final portion, and cylinders are molded within 15 minutes.
The standard field sequence is C1064 temperature, C143 slump, C231 or C173 air, C138 density, then C31 cylinders, all timed from one composite sample.
A composite sample is at least 1 ft³ (28 L) and is taken from the middle of the batch, never the first or last 10 percent of the load.
A result is usable only when it is tied to the truck, ticket number, sample time, test method, and the technician who recorded it.
Last updated: June 2026
From One Composite Sample to a Set of Results
ACI Field Testing Grade I is not seven isolated procedures memorized for a performance exam. The credential describes a technician who can take one representative sample and convert it into a set of accurate, traceable results before the concrete changes. Everything in this chapter flows from a single fact: fresh concrete is perishable. Slump loss, air loss, bleeding, temperature rise, and stiffening all begin the moment the sample leaves the truck, so the workflow is built around fixed time windows rather than personal preference.
The controlling document is ASTM C172/C172M, Standard Practice for Sampling Freshly Mixed Concrete. A composite sample is obtained by taking two or more portions at regularly spaced intervals from the middle of the batch, never from the first or last 10 percent of the load. For strength-test sampling the composite must be at least 1 ft³ (28 L) . The portions are combined and remixed with a shovel to make the material uniform before any test is run.
The C172 Time Windows Drive Everything
Two time limits from C172 govern the whole sequence and are heavily tested:
Within 5 minutes of obtaining the final portion of the composite sample, begin the tests for slump (C143), temperature (C1064 may be done first), and air content (C231 or C173) .
Within 15 minutes of fabricating the composite sample, begin molding strength specimens (C31) .
The elapsed time between obtaining the first and last portions of the composite should not exceed 15 minutes .
These windows force the technician to stage equipment, calibrate beforehand, and work without wasted motion. A correct slump value measured 20 minutes late is still an invalid result because the concrete is no longer what it was at sampling.
- Step Method Time limit What it produces
- Obtain composite C172 first-to-last ≤ 15 min ≥ 1 ft³ remixed sample
- Temperature C1064 begin ≤ 5 min °F of fresh concrete
- Slump C143 begin ≤ 5 min in. of slump
- Air content C231 / C173 begin ≤ 5 min % air
- Density / yield C138 from same sample lb/ft³, yield, % air
- Mold cylinders C31 begin ≤ 15 min strength specimens
Why This Order Is the Default
Temperature (C1064) is taken first or in parallel because the thermometer can sit in the concrete while other tools are readied, and temperature drives later interpretation. Slump (C143) comes early because it is the most slump-loss-sensitive reading and uses a fresh, unconsolidated portion. Air (C231 pressure for normalweight, C173 volumetric for lightweight or porous aggregate) and density (C138) often share the same measure or base because both fill and consolidate a known-volume container.
Cylinders (C31) come last but still must start within the 15-minute window, so the technician must not let fresh-property testing consume the entire window.
Throughout, sample identity is preserved : the technician records the truck number, the delivery ticket number , batch time, sample time, placement location, and the specific test methods. A reading with no traceability cannot support acceptance, troubleshooting, or later strength interpretation. The Grade I technician's job is to produce measured facts , not acceptance decisions, unless the project specifically assigns that authority.
Stage the Job Before the Truck Arrives
Because the clock starts at sampling, the integrated workflow really begins before any concrete arrives . A technician who is still calibrating an air meter or hunting for a tamping rod when the truck backs in will burn the 5-minute window and produce invalid data. Pre-arrival staging covers four areas:
Equipment: a verified-calibration air meter (C231) or volumetric meter (C173), slump cone and 5/8 in. rod, scoop, strike-off bar, C1064 thermometer, a clean damp sample pan or wheelbarrow, cylinder molds, scale, and the C138 measure of known mass and volume.
Forms: the field report and a place to record the C94 delivery ticket data, plus permanent markers for specimen labels.
Sample location and access: a clean, level, shaded spot near the point of discharge.
Communication: the name and number of the testing-agency supervisor, QC contact, and engineer's representative.
A Worked Example of the Window
Suppose the truck discharges at 9:00. The technician draws the first portion at 9:02 and the last at 9:05 (within the 15-minute first-to-last limit). The 5-minute clock starts at 9:05 , so slump, temperature, and air must all begin by 9:10 . The 15-minute cylinder clock also runs from the composite, so molding must begin by 9:20 . If slump and air take until 9:12 and the technician then searches for molds, the cylinders may slip past 9:20 and the strength specimens become questionable. Staging eliminates that scramble.
The same sample-control discipline that C172 demands — remix before each draw, keep the pan clean and damp, shade it from sun and wind — is what lets all five methods run cleanly off one representative sample.
Field-workflow quick recap
Run temperature, slump, and air within the C172 time windows (slump and air begun within 5 minutes of the final composite portion).
Mold strength cylinders within 15 minutes of fabricating the composite sample.
Record results on the delivery ticket/field report with the time, location, and sample identification for traceability.