- What the "22 Domains" Actually Are
- How the Two Examinations Split the Material
- Placing, Pumping, Weather, Curing, and Consolidation
- Specifications, Tolerances, and Code Documents
- Pavements, Bridge Decks, Piers, and Piles
- Formwork, Reinforcement, and Plans Reading
- Sequencing the 22 Areas in Your Prep
- Eligibility, Fees, and Registration Mechanics
- Where This Credential Gets Used
- Frequently Asked Questions
- The "22 domains" are 22 source headings from ACI's Job Task Analysis, not 22 percentage-weighted exam sections.
- Twenty-one headings are reference documents or knowledge areas; the 22nd is the separate Plans-Reading Exam.
- The written inspection exam has about 80 questions in 3 hours; plans reading has about 20 in 1 hour.
- Both exams are open book, need 70% each, and must be passed within one year of each other.
What the "22 Domains" Actually Are
Searching for the "domains" of the Concrete Transportation Construction Inspector credential, offered by the American Concrete Institute (ACI), can be misleading. Unlike many certifications, ACI does not publish a tidy list of weighted domains such as "Domain 3: 18% of the exam." What exists is the ACI Job Task Analysis (JTA) for the Concrete Transportation Construction Inspector program, approved April 5, 2021. That document lists the reference documents and knowledge sections the exam draws on, plus a plans-reading component. Counting those headings gives 22.
That distinction matters for how you study. Because the 22 lines are unweighted headings, you should not assume each one contributes equally to your score, and you should not assume any of them can be skipped. Treat the list as a map of the territory, not a budget. If you want the broader picture of how the credential fits together, start with what the CTCI certification is, then return here for the content-area detail.
Twenty-one of the lines are the reference materials: ACI terminology, ACI specifications and guides, the International Building Code, the CRSI Manual of Standard Practice, and the Manual of Concrete Inspection. The 22nd line is the Plans-Reading Exam, which is a separate test rather than a topic area inside the written exam. For a one-page refresher once you have the structure down, see the CTCI cheat sheet.
How the Two Examinations Split the Material
The credential is earned through two separately scored, open-book examinations administered by ACI-approved examiners through sponsoring groups and ACI resource centers:
| Component | Approximate Questions | Time Limit | Format | Passing Requirement |
|---|---|---|---|---|
| Inspection written examination | About 80 multiple choice | 3 hours | Open book, authorized references | At least 70% |
| Plans-reading examination | About 20 multiple choice | 1 hour | Open book, authorized references | At least 70% |
Those counts are approximate component sizes. There is no single combined 100-question exam, and you should not prepare as though there were. You must score at least 70% on each exam separately, and both must be passed within one year of each other. If you pass one and let the year lapse before passing the other, both must be retaken. Retest arrangements go through the sponsoring group that administered your session. For the scoring rules in more depth, read the CTCI passing score breakdown.
Open book changes the skill you are building. You are not memorizing the full text of 21 documents. You are learning where things live, what each document is designed to answer, and how to find a requirement quickly under a time limit. About 80 questions in 3 hours leaves little time for slow hunting, so tabbing and familiarity with each document's structure are part of your preparation. If you are weighing the effort involved, how hard the CTCI exam is covers the difficulty question directly.
Placing, Pumping, Weather, Curing, and Consolidation
A cluster of the 22 areas covers what an inspector actually watches on a pour day. These are the documents where field judgment meets written guidance.
Domains 6 and 7: ACI 304R and ACI 304.2R
ACI 304R covers measuring, mixing, transporting, and placing concrete. ACI 304.2R narrows to placing by pumping methods.
- Know the differences between delivery and placement methods and what each does to concrete in transit.
- For pumping, understand how pump lines, pressure, and slump interact with placement quality.
- Expect questions where the correct answer depends on which of the two documents governs the scenario.
Domains 8 and 9: ACI 305R and ACI 306R
These guides address hot weather and cold weather concreting, respectively.
- Associate each guide with the problems it exists to prevent: rapid moisture loss and set acceleration in heat; freezing and slowed strength gain in cold.
- Be able to distinguish protective measures that belong to one condition from those that belong to the other.
- Practice locating the guide's definitions of when each condition applies, since open-book questions often hinge on exactly that.
Domains 10 and 11: ACI 308R and ACI 309R
ACI 308R is the guide to curing; ACI 309R is the guide for consolidation.
- Curing questions test whether you understand why moisture and temperature control matter after placement.
- Consolidation questions test vibration practice and the consequences of under- and over-consolidation.
- Both connect to defects an inspector must recognize and document.
These five documents reward scenario thinking. A question might describe a deck pour on a hot afternoon and ask what an inspector should verify. Candidates who have only skimmed the guides tend to know the vocabulary but not which document answers the question.
Specifications, Tolerances, and Code Documents
The next group is the contract-and-compliance layer: the documents that define what "acceptable" means.
Domains 1, 2, and 5: Terminology, ACI 117, and ACI 301
ACI Concrete Terminology (Domain 1) underpins everything else; imprecise vocabulary leads to wrong answers across all 22 areas. ACI 117 sets tolerances for concrete construction and materials. ACI 301 is the specification for structural concrete.
- Know how to find a tolerance in ACI 117 quickly rather than trying to recall values.
- Understand ACI 301 as a specification an inspector enforces against project documents.
- Use terminology definitions to resolve any question where two answer choices differ by a single term.
Domains 12 and 20: ACI 318 and the International Building Code
ACI 318 is the building code requirements for structural concrete; the IBC is the broader building code that references concrete provisions.
- Learn how the IBC and ACI 318 relate, and which questions point to which.
- Concentrate on provisions bearing on inspection, testing, and acceptance rather than structural design theory.
- Mark the sections that address special inspection and quality assurance.
Domain 19: ACI MNL-2, Manual of Concrete Inspection
This is the document most directly about the job itself. Its coverage of inspector duties, documentation, and test procedures ties together material from many other areas.
- Treat it as your hub document and cross-reference outward from it.
- Note how it describes reporting and recordkeeping, which mirrors the employer-verified experience requirement of documentation and reporting.
Several of these overlap with the eligibility requirements, because the experience you must document includes inspection decision-making and compliance evaluation, which is precisely what these documents define.
Pavements, Bridge Decks, Piers, and Piles
The "transportation" in the credential's name shows up in a set of structure-specific guides. This is where the credential diverges from a general building-inspection focus.
Domains 13 and 14: ACI 325.9R and ACI 327R
ACI 325.9R is the guide for construction of concrete pavements. ACI 327R covers roller-compacted concrete pavements.
- Keep conventional paving and roller-compacted concrete clearly separate; they differ in materials, placement equipment, and compaction approach.
- Expect questions that test whether you can tell which method a described scenario is using.
Domain 16: ACI 345R
The guide for concrete highway bridge deck construction is one of the most directly relevant documents for transportation inspectors.
- Focus on deck-specific placement, finishing, and curing concerns.
- Connect it back to the placing, weather, and curing guides, since deck work draws on all of them.
Domains 15 and 18: ACI 336.3R and ACI 543R
ACI 336.3R reports on design and construction of drilled piers; ACI 543R is the guide to design, manufacture, and installation of concrete piles.
- Distinguish drilled piers (cast in a drilled shaft) from piles (manufactured and installed), a common point of confusion.
- Know what an inspector verifies at each stage of installation or placement.
Domains 3 and 4: ACI 213R and ACI 230.1R
ACI 213R covers structural lightweight-aggregate concrete; ACI 230.1R is the report on soil cement.
- These are narrower materials documents. Learn what each material is, where it is used, and what is distinctive about handling it.
- Because they are specialized, they are easy to under-study; do not leave them for the last day.
Formwork, Reinforcement, and Plans Reading
Domain 17: ACI 347, Guide to Formwork for Concrete
Formwork governs shape, tolerance, and safety of the finished element, and inspectors review it before concrete is placed.
- Understand what to check in forms prior to placement.
- Note the source-heading nuance: the JTA reference table lists ACI 347R while the body heading uses ACI 347. This guide uses the body heading, and you should simply be ready to recognize either form.
Domain 21: CRSI Manual of Standard Practice
The Concrete Reinforcing Steel Institute manual addresses reinforcing steel practice.
- Know the terminology and conventions for reinforcement placement and detailing.
- Pair it with plans reading, since reinforcement is communicated through drawings.
Domain 22: The Plans-Reading Exam
This is a separate test of about 20 multiple-choice questions in 1 hour, also open book with a 70% minimum. It checks whether you can extract the information an inspector needs from construction drawings.
- Practice reading dimensions, reinforcement callouts, notes, and details, not just recognizing symbols.
- Because the exam is short, speed in locating information on a sheet matters.
Sequencing the 22 Areas in Your Prep
Rather than a generic schedule, order your study by how the documents depend on each other. For deeper planning, the CTCI study guide expands on pacing; here is a sequence built around the domain list itself.
Foundation documents
- Domain 1 terminology, Domain 19 (MNL-2), Domains 2 and 5 (ACI 117, ACI 301)
- Tab your references as you go
Placement and protection
- Domains 6 through 11: 304R, 304.2R, 305R, 306R, 308R, 309R
- Work scenario questions that ask which guide applies
Transportation structures
- Domains 13 through 16 and 18, plus Domains 3 and 4
- Contrast paving vs. RCC and piers vs. piles
Codes, formwork, reinforcement, and plans
- Domains 12, 17, 20, and 21, then Domain 22
- Finish with timed mixed practice, including a plans-reading set
Reserve your final days for timed practice using the open-book references you will bring. The CTCI practice test lets you rehearse the pacing of ~80 questions in 3 hours, and reviewing your misses points you to the specific documents that need another pass.
Eligibility, Fees, and Registration Mechanics
Knowing the content is only part of the process. To sit for the inspector exams you must meet an experience pathway and a field-testing condition.
Experience pathways (any one):
- At least two years of college or technical school with 60 or more credit hours, plus two years of relevant work
- A high-school diploma or equivalent plus three years of relevant work
- Five years of relevant work
Employer-verified experience must include inspection decision-making, compliance evaluation, and documentation and reporting. Separately, you must hold current ACI Concrete Field Testing Technician Grade I certification, or have previously held it and pass its current written exam within one year of the first Inspector exam you pass. If you pass both exams and satisfy the field-testing condition but your experience is incomplete, the current program offers In-Training recognition. Full details are in the requirements guide.
Certification lasts five years. Recertification requires both Inspector exams and the field-testing condition.
On cost, fees vary by provider because exams are run through sponsoring groups and resource centers. Two examples illustrate the range:
| Provider Example | What It Lists |
|---|---|
| ACI Mid-Atlantic Resource Center (October 21, 2026 listing) | $315 for either exam; $600 for both without reference materials; $975 for both with the reference/study package |
| ACI Las Vegas | $900 chapter-member / $975 nonmember for both exams and CP-31, without a review class |
These are local provider packages, not a national fee schedule, so confirm pricing with your own sponsoring group. The standalone ACI CP-31 Transportation Inspector Reference Package is $377 for ACI members and $628 at the regular price. Since the exams are open book with authorized references, check which materials your session permits before you buy or tab anything. For a full financial picture, see the certification cost breakdown and the exam dates and scheduling guide.
Where This Credential Gets Used
The reference list tells you who values this credential. Documents on bridge decks, pavements, piers, and piles point to transportation work: state and local transportation agencies, the contractors building highways and bridges, and the testing and inspection firms that provide third-party quality assurance on those projects. Because the exam content also includes building-oriented documents like ACI 318 and the IBC, the knowledge carries over to some structural projects as well. Inspectors hold this credential to demonstrate competence in the exact decision-making and documentation tasks the employer-verified experience requirement describes.
If you are weighing career value, the CTCI jobs overview, the salary guide, and the ROI analysis go further than this domain-focused article.
Key Takeaway
Build your references around the 22 source headings, tab each document by the questions it answers, and give the Plans-Reading Exam its own preparation block. Open-book success depends on finding answers fast, not on memorizing everything.
Frequently Asked Questions
No. The 22 lines come from unweighted reference and knowledge-section headings in ACI's Job Task Analysis, plus the Plans-Reading Exam. The count is a source-heading count, not 22 percentage-weighted domains.
No. It is a separate examination of about 20 multiple-choice questions in 1 hour. The inspection written exam has about 80 questions in 3 hours. Each requires at least 70%, and both must be passed within one year of each other.
Both exams are open book with authorized references. Confirm exactly which materials are permitted with your sponsoring group, and practice locating information quickly, since time limits leave little room for browsing.
You must pass both within one year of each other. If the year passes without passing the second, both examinations must be retaken. Retest arrangements are made through your sponsoring group.
Yes. You need current ACI Concrete Field Testing Technician Grade I certification, or you must have previously held it and pass its current written exam within one year of the first Inspector exam you pass. You also must satisfy one of the experience pathways. See the CTCI certification overview for the full picture.