Last updated: April 23, 2026. Verified against the ACI CP-1(20) Technician Workbook and current ACI Certification Policies for the Concrete Field Testing Technician - Grade I program.
The ACI Concrete Field Testing Technician Grade I Exam at a Glance
The ACI Concrete Field Testing Technician - Grade I (CFTT-1, often just called "ACI Grade 1" on jobsites) is the entry-level certification issued by the American Concrete Institute for technicians who sample and test fresh concrete in the field. It is the single most widely held ACI credential in North America, with roughly 90,000+ active certificants as of 2026 and required on essentially every DOT, municipal, and major commercial concrete placement in the United States and Canada.
| Item | 2026 Detail |
|---|---|
| Credentialing body | American Concrete Institute (ACI) |
| Certification ID | Concrete Field Testing Technician - Grade I (CFTT-1) |
| Exam format | Two parts: written + performance |
| Written exam | 55 multiple-choice questions, 1 hour, closed book |
| Written passing score | 70% overall AND at least 60% on each required ASTM standard |
| Performance exam | Hands-on demonstration of 6 ASTM procedures + verbal description of C172 (sampling) |
| Performance passing | Must correctly perform/describe every step on each procedure (no partial credit) |
| Typical fee (2026) | $400-$850 combined written+performance, varies by Sponsoring Group |
| Certification term | 5 years |
| Recertification | Retake both written and performance exams |
| Prerequisites | None (no experience required) |
| Delivery | ACI-approved Sponsoring Groups (local chapters, DOTs, ready-mix associations) |
| Reference text | ACI CP-1(20) Technician Workbook for ACI Certification |
FREE ACI Concrete Field Testing Grade I practice testPractice questions with detailed explanations
What the ACI Grade 1 Certification Is and Why It Dominates the Field in 2026
Almost every set of project specifications in the United States contains some version of this sentence: "Concrete shall be tested by personnel certified as ACI Concrete Field Testing Technician - Grade I (or equivalent)." The reason is simple — ACI Grade 1 is the only nationally recognized, ANSI-accredited certification that verifies a technician can correctly perform the seven ASTM test methods that control acceptance of fresh concrete.
When a ready-mix truck arrives on a jobsite, the acceptance tests performed in the next 15 minutes determine whether the concrete can be placed, whether structural strength will meet the engineer's design, whether durability concerns (air-entrainment for freeze-thaw) are satisfied, and whether the contractor will get paid. A miscalibrated slump cone or a sloppy cylinder-molding procedure can cost a placement crew $50,000 to $500,000 in rejected concrete plus schedule impact. That is why state DOTs, the U.S. Army Corps of Engineers, the Federal Aviation Administration (FAA), and virtually every commercial general contractor in North America require ACI Grade 1 certification for any technician who handles acceptance testing.
The certification is accredited by the ANSI National Accreditation Board (ANAB) under ISO/IEC 17024 — the same standard used by BCSP, PMI, and other serious credentialing bodies. That accreditation is why state licensing boards, the AASHTO re:source program, CCRL (Cement and Concrete Reference Laboratory), and every major inspection agency accept ACI Grade 1 on its face.
Who Needs This Certification
If any of the following describe your current or target role, you need ACI Grade 1:
- QC/QA technicians at ready-mix plants performing plant-to-project split samples
- Field inspectors for geotechnical/materials engineering firms (Terracon, PSI/Intertek, ECS, Atlas, Stantec, WSP, Kleinfelder)
- DOT inspection staff on state highway and bridge projects
- General contractor QC personnel on commercial slabs, high-rises, and industrial flatwork
- Concrete subcontractors running their own acceptance testing
- Laboratory technicians pursuing higher ACI credentials (Strength Testing Technician, Concrete Laboratory Testing Technician Level 1/2)
- Engineering students and junior staff who need a field-ready credential while pursuing a PE
The test: if you will cast cylinders, measure slump, check air content, or read a concrete thermometer on behalf of a project, you need ACI Grade 1 — or the project spec is being violated.
How the Two-Part Exam Works
Unlike most professional certifications where "the exam" is a single event, ACI Grade 1 is explicitly a two-part assessment. You must pass both parts within the same exam session (or within the window allowed by your Sponsoring Group) to earn the credential. Failing either part means failing the certification.
Part 1: The Written Examination
- 55 multiple-choice questions
- 1 hour time limit (per official ACI program details at concrete.org)
- Closed book — no notes, no references, no calculator phone apps
- A basic four-function calculator is allowed (and needed for unit-weight math)
- Passing requires BOTH: at least 70% overall AND at least 60% correct on each required ASTM test method/practice. Bombing a single ASTM topic will fail you even with a high overall score.
- Questions pull exclusively from the seven ASTM standards and the CP-1 workbook; between 5 and 10 questions appear on each ASTM method
The written test emphasizes why each procedure is performed a certain way, what the acceptance tolerances are, and when a technician must reject a sample or re-test. Expect questions on sampling frequency, required time limits ("must complete slump test within 5 minutes of obtaining the final portion of the composite sample"), tolerance windows, and corrective actions.
Part 2: The Performance Examination
The performance exam requires you to physically demonstrate six of the ASTM procedures (C143, C138, C231, C173, C31, C1064) to a certified ACI Examiner, PLUS give a verbal description of ASTM C172 (sampling) — ACI does not require you to cast a live composite sample on the exam. The examiner scores your technique against a standardized checklist and must mark each step as correct.
- You must pass every procedure. Failing one = failing the performance exam.
- Some Sponsoring Groups allow retakes of individual failed procedures on the same day; others require retaking the entire performance exam.
- You bring no equipment — the Sponsoring Group provides calibrated tools and fresh concrete.
- You typically have 10-20 minutes per procedure to demonstrate. Examiners look for correct sequence, correct tolerances, and correct cleanup/documentation.
- You may talk through each step aloud. Examiners find this helpful and it helps you avoid skipping sub-steps.
If you fail the performance exam but pass the written, ACI rules allow you to retake the performance portion without retaking the written (within a time window set by your Sponsoring Group, typically 6 months). The converse is also true. But if you fail both parts, or if your retake window expires, you start over and pay the full fee again.
The 7 ASTM Standards You Must Master
This is the heart of the exam. Every question on the written test and every task on the performance exam maps to one of these seven standards. Memorize the numbers, the tolerances, and the critical time windows.
| # | ASTM Standard | What It Tests | Key Numbers |
|---|---|---|---|
| 1 | ASTM C172/C172M | Sampling Freshly Mixed Concrete | Composite sample from 2 or more portions; complete within 15 min; minimum 1 ft³ |
| 2 | ASTM C143/C143M | Slump of Hydraulic-Cement Concrete | Cone 8x4x12 in; rod 5/8 in x 24 in; 25 rods/layer x 3 layers; start within 5 min |
| 3 | ASTM C138/C138M | Density (Unit Weight), Yield, and Air Content (Gravimetric) | Measure volume ≥ 0.20 ft³ (0.75 in max agg); 25 rods/layer x 3 layers (≤0.5 ft³) |
| 4 | ASTM C231/C231M | Air Content (Pressure Method) | Type B meter; 3 layers x 25 rods; for normal-weight concrete only |
| 5 | ASTM C173/C173M | Air Content (Volumetric Method) | Roll-a-meter; for lightweight or porous aggregate; isopropyl alcohol as defoamer |
| 6 | ASTM C31/C31M | Making and Curing Concrete Test Specimens in the Field | 6x12 or 4x8 cylinders; 3 or 2 layers; initial cure 60-80°F (48 hr) or 68-78°F (high-strength) |
| 7 | ASTM C1064/C1064M | Temperature of Freshly Mixed Hydraulic-Cement Concrete | Thermometer accurate to ±1°F; immerse 3 in minimum; 2-5 min reading |
1. ASTM C172 - Sampling Freshly Mixed Concrete
This is the foundation of every other test. If the sample is bad, every subsequent result is invalid. The standard requires a composite sample - concrete taken from two or more portions of the batch at regularly spaced intervals. For truck mixers, sample from approximately the middle of the discharge (not the head or tail of the load). Never sample from the very first or very last concrete out of the chute.
Critical requirements:
- Minimum 1 ft³ (28 L) of composite sample for strength and related tests
- Complete sampling within 15 minutes from the first sample portion to the last
- Begin testing within 5 minutes after obtaining the final portion (slump, temperature, air)
- Begin molding cylinders within 15 minutes after obtaining the final portion
- Remix the composite sample with a shovel before molding or testing
Exam traps: Sampling from the first discharge, sampling from the side of the truck without representative flow, taking the entire sample from one chute position.
2. ASTM C143 - Slump Test
The workability indicator that the entire world associates with concrete testing. Use the Abrams slump cone (8 in base, 4 in top, 12 in height), a 5/8 in diameter x 24 in long tamping rod with rounded tip, and a dampened non-absorbent base plate.
The procedure in exam-ready form:
- Dampen cone and base; place cone on base; stand on foot pedals (or hold firmly)
- Fill in three equal layers by volume (approximately 2-5/8, 6-1/8, and 12 in marks)
- Rod each layer 25 times with the rounded end, distributed uniformly; penetrate just into (not through) the previous layer
- After rodding the top layer, strike off the top level with the tamping rod
- Clean concrete from around the base of the cone
- Raise the cone vertically in 5 \u00b1 2 seconds without lateral or twisting motion
- Invert the empty cone next to the slumped concrete; place the tamping rod across the top of the cone
- Measure from the bottom of the rod down to the displaced original center of the top of the slumped specimen
- Record slump to the nearest 1/4 inch (6 mm)
- Complete the test within 2-1/2 minutes from the start of filling the cone
Exam trap numbers: The entire test from start (sampling) to finish (slump reading) must be completed within the 5-minute/2.5-minute windows. If the concrete shears or collapses, you may re-test only once on a separate sample portion from the same composite.
3. ASTM C138 - Unit Weight (Density), Yield, and Air Content (Gravimetric)
This is the most math-heavy procedure. You determine the unit weight of fresh concrete, then back-calculate yield (actual volume produced per batch) and gravimetric air content (as a check against pressure or volumetric methods).
Equipment: A calibrated measure (bucket with known volume and weight).
- 0.20 ft³ minimum for maximum aggregate size up to 1 inch
- 0.40 ft³ minimum for maximum aggregate up to 1-1/2 inches
- 0.50 ft³ minimum for maximum aggregate up to 2 inches
Consolidation: Rodding (25 strokes per layer) for slumps > 3 in, vibration for slumps < 1 in, either for slumps between 1-3 in. For measures up to 0.5 ft³, fill in three layers; for larger measures, fewer layers in proportion.
Strike-off: Use a flat strike-off plate or bar. Make a final strike-off so the surface is smooth and level with the top of the measure.
The calculation (you WILL be tested on this):
Unit Weight = (Mass of measure + concrete) - (Mass of empty measure) / Volume of measure
Example: Empty measure = 10.0 lb; full measure = 40.0 lb; volume = 0.20 ft³. Unit weight = (40.0 - 10.0) / 0.20 = 150.0 lb/ft³
Yield calculation: Yield (ft³) = Total batch weight (lb) / Unit weight (lb/ft³)
Gravimetric air content: A = [(T - D) / T] x 100 Where T = theoretical density (air-free) from mix design and D = measured density. A positive value means the measured concrete has more air than theoretical.
4. ASTM C231 - Air Content by Pressure Method
The most common air-content test on normal-weight concrete. Uses a Type B pressure meter — the classic round metal bowl with a lid, pressure gauge, petcocks, and air chamber.
Procedure highlights:
- Fill in 3 equal layers, 25 rod strokes per layer, then tap sides 10-15 times with a rubber mallet after each layer
- Strike off, clean the flange, clamp the lid on
- Fill water through one petcock until it flows out the other (jog the meter to expel trapped air)
- Close petcocks, pump up pressure to the calibrated initial line
- Release pressure to the concrete; wait, stabilize, and read the apparent air content
- Apply the aggregate correction factor (G) from prior calibration: A = A₁ - G
When NOT to use C231: Lightweight or highly porous aggregates will absorb air pressure and give a false high reading. Use C173 (volumetric) instead.
5. ASTM C173 - Air Content by Volumetric Method
The "roll-a-meter" test. Required for lightweight concrete and porous-aggregate concrete (including most structural lightweight mixes). Acceptable for normal-weight concrete but slower.
Procedure highlights:
- Fill the base in 3 equal layers with 25 rod strokes per layer; tap 10-15 times per layer
- Clamp on the top section; add water to the "0" mark through the funnel
- Add isopropyl alcohol (typically a measured number of cups based on cement content) as a defoamer
- Seal the top; invert and roll/rock for at least 45 seconds then right and tap with the mallet
- Repeat rolling until successive readings differ by less than 0.25% air content
- Read the air content directly from the calibrated neck
Exam traps: Forgetting the alcohol correction, skipping the re-roll cycle, reading before the meniscus stabilizes.
6. ASTM C31 - Making and Curing Concrete Test Specimens in the Field
The heart of strength acceptance testing. The cylinders you mold today will determine whether the structure is accepted at 28 days.
Cylinder sizes and layers:
| Cylinder Size | Layers | Rods per Layer | Taps per Layer |
|---|---|---|---|
| 6 x 12 in | 3 equal layers | 25 | 10-15 with mallet |
| 4 x 8 in | 2 equal layers | 25 | 10-15 with mallet |
Note: the 4x8 cylinder uses a smaller 3/8-inch rod (not the 5/8-inch rod used for 6x12). This is a common exam trap.
Initial curing (critical and highly tested):
- Standard-cured cylinders (acceptance): maintain at 60 to 80°F for 48 hours (16-32 hr pickup window for transport), then move to final moist-cure at 73.5 \u00b1 3.5°F (70-77°F)
- High-strength cylinders (f'c > 6,000 psi): initial cure at a tighter 68 to 78°F for 48 hours
- Field-cured cylinders (cure under job conditions): cured under the same conditions as the structural element they represent; used to decide formwork removal, post-tensioning, winter protection
- Prevent moisture loss during initial curing - use curing boxes, plastic bags, damp burlap, or an insulated cure box (required in extreme temperatures)
Transport: Move specimens to the laboratory within 48 hours. Protect from jarring, temperature extremes, and moisture loss.
7. ASTM C1064 - Temperature of Freshly Mixed Concrete
The simplest procedure but the one candidates most often forget to practice for the performance exam. Use a thermometer with accuracy of \u00b11°F (\u00b10.5°C) - typically a bi-metallic dial or an RTD digital thermometer.
Procedure:
- Temperature must be measured in a sample that provides at least 3 inches (75 mm) of concrete cover around the thermometer's sensor
- Insert the thermometer so the sensor is fully immersed
- Leave in place minimum 2 minutes, maximum 5 minutes - or until the reading stabilizes
- Record temperature to the nearest 1°F (0.5°C)
- Complete measurement within 5 minutes after obtaining the sample
Why it matters: ACI 301 typically limits fresh concrete temperature to 50-90°F for normal placements, and hot-weather (above 90°F) and cold-weather (below 50°F) concreting require additional controls. The technician's temperature reading is what triggers those contract provisions.
Quick Reference: Time Limits, Tolerances, and Numbers to Memorize
| Requirement | Value | Source |
|---|---|---|
| Minimum sample size (acceptance tests) | 1 ft³ | C172 |
| Max sampling window | 15 minutes | C172 |
| Start air/temp/slump test within | 5 min of final sample | C172 |
| Start molding cylinders within | 15 min of final sample | C172 |
| Slump cone raise time | 5 \u00b1 2 seconds | C143 |
| Slump total test time | 2-1/2 minutes | C143 |
| Slump reading precision | 1/4 inch | C143 |
| Tamping rod (6x12 cyl / slump) | 5/8 in x 24 in, rounded tip | C31, C143 |
| Tamping rod (4x8 cyl) | 3/8 in x 12 in, rounded tip | C31 |
| Rods per layer (standard) | 25 | C31, C143, C138, C231, C173 |
| Mallet taps per layer | 10-15 | C138, C231, C173, C31 |
| Standard-cure initial temp (normal) | 60-80°F for 48 hr | C31 |
| Standard-cure initial temp (high-strength) | 68-78°F for 48 hr | C31 |
| Final moist cure temperature | 73.5 \u00b1 3.5°F | C31 |
| Thermometer accuracy | \u00b11°F | C1064 |
| Temperature reading wait | 2-5 minutes | C1064 |
| Volumetric air rolling time | \u2265 45 seconds | C173 |
| Unit weight constant for yield | None - direct measurement | C138 |
| Written exam pass mark | 70% overall AND \u226560% on each ASTM | ACI policy (CPP 610.1) |
| Written exam time limit | 1 hour | ACI policy |
| Questions per ASTM topic | 5 to 10 | ACI policy |
ACI Grade 1 Exam Fees in 2026
Unlike most certifications with a single published fee, ACI Grade 1 is delivered by local Sponsoring Groups (state ready-mix associations, local ACI chapters, DOT training branches, universities). Each Sponsoring Group sets its own fee within ACI's program guidelines. Typical 2026 pricing:
| Fee Type | Typical Range (2026) |
|---|---|
| Combined written + performance exam (initial, member) | $450 - $600 |
| Combined written + performance exam (non-member) | $575 - $850 |
| Re-certification (retake both parts after 5 years) | Same as initial (no CEU pathway) |
| Written-only or performance-only retake | $235 - $450 |
| CP-1(20) Technician Workbook (required text) | $35 - $70 printed / $35 digital |
| Optional pre-exam training class | $50 - $325 |
| Typical total first-time budget | $500 - $900 |
Recent 2026 published fees: CRMCA (Colorado) charges $498 member / $768 non-member at CDOT HQ, $548-$848 elsewhere. ACI SoCal charges $610 member / $660 non-member (increasing to $620/$670 in July 2026). ACI Carolinas lists $333 member / $403 non-member for a performance-only retest. Las Vegas Chapter charges $500 member / $575 non-member for full certification.
Employers often pay for certification directly (ready-mix producers, inspection firms, DOTs). If you are paying out of pocket, budget $500-$900 total depending on chapter membership and whether you add a training class.
Sponsoring Groups publish exam schedules 2-6 months in advance. Popular groups sell out quickly during spring and early summer (when construction ramps up), so register early if you have a project deadline.
4-6 Week Study Plan
For candidates studying ~5-8 hours per week. Compress to 3 weeks by doubling weekly hours and scheduling hands-on practice earlier.
Week 1: Foundations and ASTM C172, C1064
| Day | Task | Hours |
|---|---|---|
| 1-2 | Read CP-1(20) Chapters 1-3 (program overview, safety, general concepts) | 3 |
| 3 | Deep-read ASTM C172 (sampling); outline composite sample rules | 1.5 |
| 4 | Deep-read ASTM C1064 (temperature); memorize \u00b11°F tolerance | 1 |
| 5 | First practice quiz (20 questions on C172 + C1064) | 1 |
| 6-7 | Hands-on walk-through with a mentor if possible; otherwise, watch ACI training videos | 2 |
Target: 80% on quiz covering sampling and temperature by end of week.
Week 2: Slump (C143) and Temperature Review
| Day | Task | Hours |
|---|---|---|
| 1-2 | Deep-read ASTM C143; write out the 10-step procedure from memory | 2 |
| 3 | Study slump traps: shear/collapse, re-test rules, timing | 1 |
| 4 | Rod a slump cone in water/sand at home if you cannot access concrete | 1 |
| 5 | Practice quiz on C143 (30 questions) | 1 |
| 6 | Review weak topics from quiz | 1 |
| 7 | Full-length practice written test (55 Q) focusing on weeks 1-2 material | 1.5 |
Target: Consistent 5-second cone raises; 80% on C143 quiz.
Week 3: C138 (Unit Weight/Yield) and Math Drills
| Day | Task | Hours |
|---|---|---|
| 1 | Deep-read ASTM C138; mark every equation | 1.5 |
| 2 | Work 10 unit weight problems by hand | 1 |
| 3 | Work 10 yield problems; understand relative yield interpretation | 1 |
| 4 | Work 10 gravimetric air content problems | 1 |
| 5 | Calibration check procedure for unit weight measures | 0.5 |
| 6 | Mixed problem set: unit weight + yield + air (20 problems) | 1.5 |
| 7 | Written practice quiz covering C138 (30 Q) | 1 |
Target: Solve unit weight + yield + air problems in under 90 seconds each, without error.
Week 4: Air Content (C231 and C173)
| Day | Task | Hours |
|---|---|---|
| 1-2 | Deep-read C231; memorize Type B meter procedure step-by-step | 2 |
| 3 | Study aggregate correction factor G; practice A = A₁ - G calculations | 1 |
| 4 | Deep-read C173 (volumetric); understand when C173 is required (lightweight) | 1.5 |
| 5 | Practice the 45-second roll timing; visualize rocking technique | 0.5 |
| 6 | Practice quiz on C231 + C173 (40 Q) | 1 |
| 7 | Differences quiz: C231 vs C173 decision tree | 1 |
Target: Identify the correct air method from a mix description 100% of the time.
Week 5: C31 Cylinders and Full Practice Tests
| Day | Task | Hours |
|---|---|---|
| 1-2 | Deep-read ASTM C31; build a chart of 6x12 vs 4x8 rod/layer differences | 2 |
| 3 | Memorize initial cure temperatures (60-80°F standard, 68-78°F high-strength) | 1 |
| 4 | Study field-cured vs standard-cured purpose | 1 |
| 5 | Practice quiz on C31 (30 Q) | 1 |
| 6 | Full-length written practice exam under time (55 Q in 1 hour) | 1.5 |
| 7 | Error log review; re-read weak ASTM sections | 2 |
Target: 80%+ on full-length practice exam.
Week 6: Performance Exam Rehearsal and Final Review
| Day | Task | Hours |
|---|---|---|
| 1 | Talk-through rehearsal: narrate each of the 7 procedures aloud | 1.5 |
| 2 | Second full practice written exam | 2 |
| 3 | Spot-review any procedure still uncertain | 1 |
| 4 | Final quiz drills: 50 mixed questions from all 7 ASTMs | 1.5 |
| 5 | Light review - stop cramming; sleep; hydrate | 0.5 |
| 6 | EXAM DAY | - |
Total ~45-55 hours over 6 weeks. Repeat candidates can typically compress to 2-3 weeks by focusing on the domain that caused the first failure.
Recommended Resources (2026)
Official ACI Resources
- ACI CP-1(20) Technician Workbook for ACI Certification of Concrete Field Testing Technician - Grade I (required - covers every ASTM procedure, includes sample questions)
- ACI Field Reference Manual: ACI 301 Specifications (useful for context on cold/hot weather limits)
- ACI Certification Policies (free PDF from concrete.org - outlines retake rules and certification cycle)
- ACI On-Demand Training (~$150-$400 per topic; includes proctored performance video demonstrations)
ASTM Standards (required reading for the written exam)
- ASTM C172/C172M - Standard Practice for Sampling Freshly Mixed Concrete
- ASTM C143/C143M - Test Method for Slump of Hydraulic-Cement Concrete
- ASTM C138/C138M - Test Method for Density (Unit Weight), Yield, and Air Content of Concrete
- ASTM C231/C231M - Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
- ASTM C173/C173M - Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method
- ASTM C31/C31M - Standard Practice for Making and Curing Concrete Test Specimens in the Field
- ASTM C1064/C1064M - Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete
Individual ASTM PDFs are roughly $60-$75 each; the 7-standard set can be purchased from ASTM for $300-$400, but the CP-1 workbook summarizes them for the exam so you do not strictly need to buy the full PDFs.
Third-Party Prep Providers
- NRMCA (National Ready Mixed Concrete Association) - pre-exam classes at member plants
- State ready-mix associations (Texas Aggregates & Concrete Association, California NRMCA, Florida Concrete, etc.) - several host annual boot-camp weekends
- Local ACI chapter training - often the same venue as the exam
- YouTube channels - Tyler Ley, ACI Official, and university civil engineering channels publish solid walk-throughs of each ASTM method
Free Supplements
- OpenExamPrep ACI Grade 1 practice bank - free, AI-explained, procedure-aligned
- ACI 318 summary handouts from universities teaching concrete design (useful context)
- AASHTO T-procedures (equivalent to ASTM C-methods; useful if you work on DOT projects)
Performance Exam Common Pitfalls
Candidates fail the performance exam far more often than the written. The examiner is watching for disciplined, consistent technique — not speed. Avoid these traps:
- Skipping the cone dampening step on the slump test. Water absorbs concrete paste; you must dampen the cone, base, and rod and wipe dry before starting.
- Raising the slump cone in the wrong time window. Too fast (<3 seconds) shocks the specimen; too slow (>7 seconds) drags. Practice the 5-second count.
- Twisting or pushing laterally when raising the cone. Lift straight up with steady hands.
- Rodding through the previous layer instead of just into it. The rod should barely penetrate the surface below.
- Under-rodding. Count aloud; 25 strokes is 25 strokes, not 20. Spread strokes evenly across the cross-section.
- Forgetting the mallet taps after rodding. Each layer gets 10-15 taps on the outside of the measure/cylinder with a rubber mallet.
- Reading air content before the meter stabilizes. Wait a few seconds for needle/meniscus to settle.
- Using the wrong rod for 4x8 cylinders. The 3/8-in x 12-in rod is required, not the standard 5/8-in rod.
- Skipping strike-off with the tamping rod before the straightedge. C143 specifically calls for the top of the cone to be struck off with the rounded end of the tamping rod before you raise it.
- Mis-placing the thermometer. The probe must have 3 inches of concrete cover in all directions - not just be stuck in the edge of a sample.
- Wrong sampling location on the truck. Sample from the middle of the load, never the first or last 10%.
- Talking while the examiner is writing. Pause for the examiner to check the box. Your technique is being graded, not your narration speed.
The examiner is typically looking for 90%+ correct step execution. A small error may be correctable with a brief callback ("I meant to tap 12 times, let me continue") but a missed major step (not striking off, not rodding the correct number) will fail that procedure. Fail one procedure, fail the performance exam.
Test-Day Tips (Both Parts)
For the Written Exam:
- Arrive 30 minutes early with two forms of ID. Many Sponsoring Groups require a photo ID and a second credential.
- Bring a basic four-function calculator. Phones and programmable calculators are prohibited. Some Sponsoring Groups provide calculators - confirm with your registration email.
- Bring several #2 pencils and a pink eraser (even on computer-delivered tests, scratch paper + pencil is typical).
- Read every question twice. The CP-1 workbook's sample questions are similar to the real exam - several answer choices sound correct until you re-read the question stem for the word "EXCEPT" or "NOT."
- Flag and move on. 1 hour for 55 questions = roughly 65 seconds per question. If you cannot solve a unit-weight math question in 60-75 seconds, flag it and return after you have answered every easy question.
- Guess if you do not know. There is no wrong-answer penalty - leave nothing blank.
For the Performance Exam:
- Dress for concrete. Boots, gloves, and clothes you do not mind getting splattered. Some sites require high-vis and a hard hat.
- Narrate each step aloud. "Placing the dampened base plate on a level surface. Positioning the cone and stepping on the foot pedals. First layer - scooping and filling to the 2-5/8 inch mark. Twenty-five rod strokes, distributed uniformly..." This keeps you from skipping a step.
- If you catch an error, correct it immediately and say so. "I rodded that layer 23 times; I need to add two more strokes." Examiners respect self-correction on minor issues.
- Do not rush. A 15-minute procedure done correctly beats a 6-minute procedure done wrong.
- Clean up. Some examiner scoresheets include cleanup/documentation. Rinse equipment, document the sample, label cylinders with your ID, date, truck/ticket, and slump/air if measured.
After the Exam:
- Results are usually provided the same day (examiner tabulates both parts) or within 1-2 weeks if ACI headquarters reviews the paperwork.
- Your wallet card and digital certificate typically arrive 2-6 weeks after ACI processes the results.
- You can list the certification on LinkedIn and your resume immediately after the Sponsoring Group confirms passing.
Certification Term, Renewal, and the 5-Year Clock
The ACI Grade 1 credential is valid for exactly 5 years from the date you pass both parts. ACI does not offer continuing-education renewals for Grade 1 - you must retake both the written and performance exams to recertify.
Why Retesting (Not CEUs)
ACI's position is that field testing is a skills-based credential and skills atrophy. A technician who has been running a ready-mix plant for 5 years may have stopped personally performing C231 pressure-meter tests years ago; retesting ensures every certified field technician can currently demonstrate the methods on demand.
Recertification Timing
- You can re-test up to 6 months before your current certification expires (the new 5-year term starts from the old expiration date, not the retest date).
- Between expiration and retesting, your certification is lapsed - you cannot legally act as a certified technician on specs that require "ACI Grade 1 or equivalent."
- Sponsoring Groups sometimes offer recertification-only exam dates at reduced fees.
Converting to Higher ACI Credentials
If you plan to continue working in materials testing, consider moving up the ACI ladder:
| Higher Credential | Prerequisites | What It Adds |
|---|---|---|
| ACI Concrete Field Testing Technician - Grade II | Grade I active + written + performance | Advanced field tests (static modulus, rebound hammer, etc.) |
| ACI Concrete Strength Testing Technician | None, but Grade I recommended | Cylinder capping, break testing, lab compressive strength |
| ACI Concrete Laboratory Testing Technician - Level 1 | Strength Tester recommended | Full lab suite (agg gradation, moisture, absorption) |
| ACI Concrete Laboratory Testing Technician - Level 2 | Level 1 + experience | Advanced lab (petrography, ASR, air-void analysis) |
| ACI Concrete Flatwork Finisher / Technician / Associate | Flatwork experience | Slab-on-grade specialization |
| ACI Concrete Construction Special Inspector | ICC/ACI joint - field experience | Structural special inspection under IBC |
Many inspection agencies and ready-mix plants maintain a credential ladder for their technicians - Grade 1 in year 1, Strength Tester in year 2, Lab Level 1 by year 3. Promotions and pay raises typically track the ladder.
Career and Salary Impact in 2026
Per U.S. Bureau of Labor Statistics (OCC 17-3029, Engineering Technologists and Technicians, All Other; includes construction materials testers; May 2024 OES data), the median annual wage was $72,230 with the top 10% earning above $108,910. Concrete field testing is a common entry-level role at materials engineering firms that feeds into senior inspector, project manager, and engineering-technician career tracks.
| Role | Median Compensation (2026) |
|---|---|
| Concrete Field Technician (entry, 0-2 yr) | $42,000 - $58,000 |
| Field Technician II / Senior Technician | $55,000 - $75,000 |
| Materials Testing Project Manager | $75,000 - $105,000 |
| Quality Control Manager (ready-mix plant) | $68,000 - $95,000 |
| Traveling Inspector on DOT mega-projects | $70,000 - $95,000 + per diem |
| Materials Engineering Branch Manager | $95,000 - $140,000 |
Pay bump from ACI Grade 1: Materials engineering firms typically require Grade 1 within 90 days of hire for any field role. Many pay a $1-$3/hour wage differential or a $1,500-$3,000 annual bonus for each active ACI certification on top of base pay. Ready-mix producers often offer similar step-up schedules.
Why the credential ladder drives promotions: Senior field technicians running DOT projects typically hold Grade 1 + Grade 2 + Strength Tester + OSHA 10 + nuclear gauge (Troxler) operator + first aid/CPR. Each credential adds ~$1/hour and opens a project scope (federal, DOT, nuclear-gauge sites). A 25-year-old with 4 credentials can out-earn a 45-year-old with one.
Common Mistakes That Cause Candidates to Fail
- Memorizing the CP-1 workbook instead of reading the ASTM standards. CP-1 summarizes; the ASTM standards are authoritative. Exam questions sometimes quote ASTM verbatim.
- Confusing C231 and C173 use cases. Pressure method (C231) fails on lightweight/porous aggregates. Volumetric method (C173) works on both but is slower. Know when to pick which.
- Mixing up rod size between cylinder sizes. 5/8" x 24" for 6x12 and slump; 3/8" x 12" for 4x8 cylinders.
- Forgetting the strike-off with the tamping rod on the slump test before using a straightedge.
- Not memorizing the math. Unit weight, yield, and gravimetric air are quick calculations - but under exam pressure, candidates rush and miscount decimals. Practice at least 30 problems.
- Over-studying concrete chemistry (Type I vs Type III cement, pozzolans) instead of testing procedures. The exam is 95% test-method focused.
- Skipping the CP-1 sample questions. They appear in the back of the workbook and several similar-style questions appear on the actual written exam.
- Underestimating the performance exam. Many candidates assume if they pass the written, the performance exam is a formality. It is not - examiners routinely fail candidates who never physically practiced with real concrete.
- Arriving to the performance exam with dress shoes or no gloves. Concrete is abrasive and caustic; you need PPE and field-appropriate clothing.
- Ignoring the time windows (5-minute start, 15-minute molding, 2.5-minute slump). These are tested in multiple questions and are procedure-critical on the performance.
Related ACI Credentials to Know
The CFTT-1 is the start of the ACI ladder. Your trajectory depends on what you want to do next:
- ACI Concrete Field Testing Technician - Grade II - adds advanced tests (static modulus, unit weight of hardened concrete core sections, rebound hammer, penetration resistance). Typically taken 1-3 years after Grade 1 by technicians on federal/DOT work.
- ACI Concrete Strength Testing Technician - the laboratory companion to Grade 1. Covers cylinder capping (sulfur, neoprene, or unbonded caps), compression testing machine operation, and test report generation. No experience prerequisite but Grade 1 is assumed knowledge.
- ACI Concrete Laboratory Testing Technician - Level 1 and Level 2 - full lab suite for aggregate gradation, moisture, density, alkali-silica reactivity, petrographic examination.
- ACI Concrete Flatwork Finisher / Technician / Associate - hands-on placement/finishing certification for concrete contractors working on slabs.
- ACI Concrete Construction Special Inspector - joint ACI/ICC credential required under IBC Chapter 17 for special inspection of structural concrete.
- ACI Adhesive Anchor Installer - specialty credential required by IBC for post-installed adhesive anchor systems.
Most materials testing firms encourage Grade 1 + Strength Tester + Lab Level 1 within the first 3 years on staff. That triple-credential package typically unlocks $10,000-$15,000 in additional annual compensation compared to a single-credentialed technician.
Final CTA: Start Practicing Now
The ACI Grade 1 exam rewards repetition and procedural discipline. You cannot talk your way through an ASTM C143 cone raise - you either practiced 5-second lifts or you did not. You cannot guess your way through unit weight calculations - you either ran 30 practice problems or you miscounted decimals under pressure.
FREE ACI Concrete Field Testing Grade I practice testPractice questions with detailed explanations
Official Sources
- ACI Certification page (CFTT-1): https://www.concrete.org/certification/certificationfortechnicians.aspx
- ACI CP-1(20) Technician Workbook: https://www.concrete.org/store/productdetail.aspx?ItemID=CP120
- ACI Certification Policies: https://www.concrete.org/certification/certificationpolicies.aspx
- ASTM International - Concrete Standards: https://www.astm.org/products-services/standards-and-publications/standards/concrete-and-concrete-aggregates-standards.html
- NRMCA Certification resources: https://www.nrmca.org/association-resources/education/certifications/
- BLS OES 17-3029: https://www.bls.gov/oes/current/oes173029.htm
- AASHTO re:source (QC program using ACI-certified technicians): https://www.aashtoresource.org
Disclaimer: This guide is informational only. Always verify current fees, exam schedules, and policies with your local ACI Sponsoring Group and at concrete.org. ACI, the ACI logo, and all ACI certification program names are trademarks of the American Concrete Institute. ASTM and all ASTM standard designations are trademarks of ASTM International. OpenExamPrep is not affiliated with or endorsed by ACI or ASTM.
Buy on Amazon