ACI Certification Cheat Sheet 2026

The 30 highest-yield ACI Certification facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. The aggregate correction factor (A) used in the pressure method air content test (ASTM C231) corrects for: → Air voids within aggregate particles that are not part of the paste air void system
2. Why are practice tests considered essential for ACI certification exam preparation? → They familiarize candidates with exam formats and timing
3. According to ASTM C39, what is the specified loading rate for applying a compressive force to a standard 6x12 inch concrete cylinder? → 35 ± 7 psi/s
4. When transporting fresh concrete test cylinders to the laboratory per ASTM C31, specimens must be protected from: → Vibration, jolting, and rough handling that could damage the specimens
5. A compressive testing machine must be accurate to within what percentage of the indicated load throughout the range being used, per ASTM E4? → ± 1.0%
6. What is the best way to access ASTM standards required for ACI certification preparation? → Purchase directly from ASTM International
7. An inspector observes that the concrete delivered to the site has a slump 3 inches higher than specified. What is the correct course of action? → Reject the load and notify the contractor and engineer of record before placement
8. Which of the following conditions is most likely to cause plastic shrinkage cracks to form on the surface of freshly placed concrete? → High wind speed and low humidity.
9. Per ASTM C1064, how long must a thermometer be immersed in fresh concrete before the temperature reading is recorded? → A minimum of 2 minutes or until the reading stabilizes
10. The saturated surface-dry (SSD) condition of aggregate is used as the reference state in mix design because: → It requires no moisture correction to batch water calculations
11. The volumetric method (ASTM C173) is preferred over the pressure method (ASTM C231) when testing: → Lightweight aggregate concrete or concrete made with porous aggregate
12. After the top surface of a freshly cast cylinder is struck off, it must be finished so that it departs from a true plane by no more than: → 1/16 inch (1.6 mm)
13. According to ACI 318, the maximum w/cm ratio for concrete subjected to deicing chemicals (severe freezing-and-thawing exposure) is: → 0.40
14. What is the specified rate of load application when testing concrete cylinders for compressive strength per ASTM C39? → 35 ± 7 psi/s (0.25 ± 0.05 MPa/s)
15. Which ACI document provides the standard practice for selecting proportions for normal, heavyweight, and mass concrete? → ACI 211.1
16. How does obtaining an ACI certification benefit career growth? → It validates expertise and increases job opportunities
17. Per ASTM C31, freshly cast concrete specimens must be protected from vibration, shock, and disturbance for a minimum of how long after molding? → 24 hours
18. Which ASTM standard governs the flexural strength of concrete using a simple beam with third-point loading? → ASTM C78
19. When making concrete test cylinders per ASTM C31, how long must the molds remain undisturbed in the field after casting? → A minimum of 24 hours and a maximum of 48 hours, stored at 60–80°F (16–27°C)
20. What is the maximum permissible departure from perpendicularity of the end surface of a concrete test cylinder when measured with a square? → 0.5°
21. Per ASTM C31, concrete with a slump of 1 inch (25 mm) or less must be consolidated in cylinder molds by: → Internal vibration
22. When performing the slump test per ASTM C143, the concrete is placed in the mold in: → 3 layers
23. Which ASTM standard is the practice for making and curing concrete test specimens in the field? → ASTM C31
24. What is the maximum permitted length-to-diameter ratio (L/D) for a concrete test cylinder per ASTM C39? → Between 1.8D and 2.2D (where D is diameter), with 2.0D being the standard
25. When striking off excess concrete from the top of a unit weight measure per ASTM C138, the preferred instrument is: → A flat plate or piece of plate glass
26. What should candidates focus on when studying the ACI certification workbook? → Both practical procedures and theoretical concepts
27. A concrete finisher is preparing to perform the initial floating of a freshly placed slab. Which of the following is the primary purpose of bull floating? → To embed large aggregate, level the surface, and remove screed marks.
28. For a 4×8-inch concrete test cylinder made from concrete with a slump between 1 and 3 inches, how many layers and rods per layer are required per ASTM C31? → Two layers, 25 rods per layer
29. Which ACI certification is specifically designed for concrete field testing technicians at the entry level? → ACI Concrete Field Testing Technician – Grade I
30. The amount of time that has passed between when the slump cone is first filled and when it is removed shall not exceed: → 2 1/2 minutes