CSTT Exam Domains 2026: Complete Guide to All 4 Content Areas

How the CSTT Exam Is Built

The Concrete Strength Testing Technician credential is issued by the American Concrete Institute (ACI), and examinations are administered through ACI-approved Sponsoring Groups and resource centers. If you are new to the credential itself, start with What Is CSTT Certification? and then come back here for the content breakdown.

The exam objectives come from ACI's Job-Task Analysis, approved February 29, 2020 and editorially updated February 8, 2022. The JTA organizes the knowledge and skills into four headings, and each heading corresponds to one ASTM standard. This is a critical distinction: those four headings are unweighted official examination-objective areas. They are not four equally weighted domains, and you should not assume each one contributes exactly one quarter of anything. What the policy does tell us is how the written exam enforces coverage of every standard, which we cover in the scoring section below.

The program has two components: a written examination and a separate performance examination. Candidates must pass both within one year. There is no specific education or work-experience prerequisite, a point explored further in CSTT Requirements 2026: Eligibility, Prerequisites & How to Qualify.

The Four Content Areas at a Glance

The program's technical basis is C617/C617M-15, C1231/C1231M-15, C39/C39M-18 and C78/C78M-18. Notice that the first two standards are about preparing cylinder ends so they can be loaded evenly, the third is the compression test itself, and the fourth moves from cylinders to beams.

Because the standards build on each other, a weakness in Area 1 or 2 tends to create confusion in Area 3, where the capping or unbonded-cap method you used affects how you interpret the test setup. The sections below walk through each area in the order candidates typically learn them.

Area 1: Capping with ASTM C617/C617M

On the written exam, expect questions that ask you to identify the correct step, material, or condition from a short scenario. The performance side is hands-on: you will be assessed on how you carry out the capping procedure against a checklist. The practical consequence is that memorizing a requirement is not enough. You need to be able to describe and then physically perform the sequence in the right order.

Because the exam is closed book, you cannot look up a tolerance or timing requirement. Learn the numbers and conditions from the workbook until you can recall them without prompting. Our CSTT Cheat Sheet 2026: One-Page Review of Must-Know Facts is a good place to consolidate them once you have worked through the source material.

Area 2: Unbonded Caps with ASTM C1231/C1231M

Candidates often underestimate this area because it feels like a short supplement to capping. In practice, the exam treats it as its own standard, and the written exam is built so that every standard receives coverage. A candidate who skims C1231 can lose enough points in that one area to fail the per-standard minimum, even with strong results elsewhere.

The most useful study technique here is contrast. Build a side-by-side list of how C617 bonded capping and C1231 unbonded caps differ in materials, preparation, and the checks you perform. Questions frequently hinge on whether you can tell which practice a described situation falls under.

Area 3: Compressive Strength with ASTM C39/C39M

This is the area where the calculator allowance matters. Simple non-programmable calculators are permitted on the performance exam, and strength calculation from load and area is a natural place for arithmetic to appear. Practice working the calculation by hand and with a basic calculator, paying attention to units and to rounding conventions as the standard directs.

Fracture patterns deserve dedicated attention. Being able to look at a description or sketch and identify an acceptable versus a defective break is a common knowledge check, because an unusual fracture can indicate a problem with capping, specimen preparation, or the testing machine. This ties Area 3 directly back to Areas 1 and 2, which is why the technical basis is best studied as a connected whole.

For a sense of how demanding the material is relative to the credential's reputation, see How Hard Is the CSTT Exam? Complete Difficulty Guide 2026.

Area 4: Flexural Strength with ASTM C78/C78M

Candidates who work mostly with cylinders in their daily job can find this area the least familiar. It involves a different specimen shape, a different loading geometry, and a different formula. The location of the fracture within the loaded span matters because it determines how the result is calculated and whether it is valid, so give extra time to that decision logic.

Since this standard is easy to neglect when your lab rarely breaks beams, build in deliberate review. A weak result here counts against the 60% per-standard threshold just as much as any other area would.

Scoring Rules That Shape How You Study

The written examination is one hour, closed book, and multiple choice. The current ACI program page describes approximately 40 questions with at least eight per standard, while Certification Program Policy CPP 620.2-19 describes approximately 35-40 questions with 8-10 per standard. Treat the count as an approximation rather than a fixed number; what is consistent across both sources is that every standard receives meaningful, guaranteed coverage.

Passing requires at least 60% on each standard and at least 70% overall. That dual requirement is the most important structural fact for planning your preparation, and it is explained in more depth in CSTT Passing Score 2026: Exactly What You Need to Pass.

For discussion of what outcomes look like across candidates, see CSTT Pass Rate 2026: What the Data Shows.

The Performance Exam Covers All Four Procedures

The performance examination is separate from the written test, also closed book, and assesses all four procedures using pass/fail checklists. That means you are expected to demonstrate capping, unbonded cap use, compressive strength testing, and flexural strength testing, not just describe them.

• Checklist-driven grading: Each procedure is evaluated against specific steps. Skipping or reordering a required step is the typical way candidates lose a procedure.
• Second trial: If you fail a practical procedure, you may make a second same-day trial.
• Re-examination scope: Subsequent re-examination covers the entire failed written or performance component, not just the single procedure or question group you missed.
• One-year window: If you do not complete both components within one year, both must be retaken.

Because the written and practical components test the same four standards from two angles, the most efficient preparation links them. When you read a step in the workbook, rehearse it physically if you can, and when you perform a procedure, say aloud why each step exists. For help turning this into a plan, see CSTT Study Guide 2026: How to Pass on Your First Attempt.

Workbook, Fees, and Local Sessions

The current workbook is CP-19, 25th Edition (2022). ACI also accepts the 23rd and 24th editions because their technical basis is identical. The 25th-edition workbook does not include the ASTM standards, so factor that into your materials planning. It is listed at USD 71 for ACI members and USD 136 for non-members. ACI identifies first-printing errata, but the linked document requires sign-in, so check for corrections before relying on a newly purchased copy.

Exam pricing is set locally through Sponsoring Groups, so there is no single national tariff. Two verified 2026 examples illustrate the range:

Note that the Ohio Concrete member prices reflect Ohio Concrete membership, not ACI membership rates. The Las Vegas Chapter lists an October 24, 2026 session as a dated example. Always confirm current pricing and availability with your local Sponsoring Group; for the broader picture, see CSTT Certification Cost 2026: Complete Pricing Breakdown and CSTT Exam Dates 2026: Testing Windows, Deadlines & Scheduling.

Once certified, the credential lasts five years, and recertification requires passing both examinations again. Plan for that renewal cycle when weighing the investment, as discussed in Is the CSTT Certification Worth It? Complete ROI Analysis 2026.

Sequencing Your Preparation by Area

Because the standards build on each other, the order in which you study them matters more than the total hours. Here is a sequence that respects those dependencies and the 60%-per-standard rule.

Schedule your weakest standard earliest in the final review, since a single low area can fail you regardless of overall performance. The CSTT Exam Prep practice tests let you drill by standard so you can see whether any one area is dragging you toward the 60% floor.

Employers that rely on this credential are typically organizations that produce, place, or verify concrete, where accurate strength results matter. For a look at the roles and employers, see CSTT Jobs, and for earnings context see CSTT Salary Guide 2026: Complete Earnings Analysis. If you want a broader foundation first, What Is CSTT? is a good primer.

Frequently Asked Questions