ATT Cheat Sheet 2026

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

1. In the sand equivalent test (ASTM D2419), the purpose of the flocculating solution (calcium chloride) is to: → Cause clay and fine dust to flocculate and settle into a distinct layer
2. What is the maximum allowable lightweight pieces (coal and lignite) in fine aggregate per ASTM C33 for concrete subject to surface wear? → 0.5%
3. What is the PRIMARY purpose of continuing education requirements in Los Angeles Abrasion Testing for ATT professionals? → Maintaining current knowledge and competency as the field evolves
4. Which ASTM standard covers the test method for flat particles, elongated particles, or flat and elongated particles in coarse aggregate? → ASTM D4791
5. Which aggregate characteristic directly affects the calculation of batch weights in mix design using specific gravity? → Volume of aggregate per unit mass (reciprocal of specific gravity)
6. Why is determining void content in aggregates important? → To estimate cement requirements
7. In the wire basket method for coarse aggregate (ASTM C127), what is the purpose of the wire basket? → To hold the aggregate submerged while its mass is determined in water
8. When testing for lightweight pieces per ASTM C123, the test result is expressed as: → Percentage by mass of lightweight pieces
9. When sampling aggregate from a flowing discharge stream, increments should be collected: → At regular time intervals throughout the entire discharge period
10. If an aggregate fails the ASTM C40 color test, what is the recommended next step per the standard? → Perform a mortar strength test per ASTM C87
11. Chert with a bulk specific gravity less than 2.40 is considered a deleterious substance in coarse aggregate because: → It has poor freeze-thaw durability and causes pop-outs
12. Which test method determines the specific gravity of coarse aggregates? → ASTM C127
13. Which equipment is essential for performing a mechanical sieve analysis? → Mechanical sieve shaker
14. Which ASTM standard is used to determine lightweight pieces in aggregate (such as coal and lignite)? → ASTM C123
15. What shape is the working end of the tamping rod specified in ASTM C29? → Hemispherical
16. Which standard of practice is MOST important for ensuring quality in Aggregate Sampling & Reduction? → Following evidence-based protocols while adapting to specific circumstances
17. In Fine Aggregate Quality Tests, what is the FIRST step a ATT professional should take when encountering a new case or situation? → Conduct a comprehensive assessment and gather all relevant information
18. Which of the following is a valid sampling location for aggregate in transport? → From a stopped conveyor or truck bed.
19. When sampling from a truck or rail car, at how many approximately equal depth-interval locations across the load should increments be taken? → At least three locations across the load
20. When collecting samples from aggregate bins or hoppers, where within the bin should sampling be avoided? → The sides and corners where material stagnates and may not be representative
21. When sampling from a stockpile, what is the most important principle to follow? → Collect from various depths and locations.
22. How should a field sample be reduced to testing size? → Using a mechanical splitter or quartering method.
23. What action should be taken if a field sample arrives at the laboratory with obvious segregation in the container? → Re-mix the entire container thoroughly before reducing the sample
24. What is the primary reason that aggregates with high absorption values can be problematic in concrete? → They may absorb mixing water, effectively lowering the water-cement ratio
25. The particle index test (ASTM D3398) measures aggregate quality based on: → Particle shape and surface texture using void content
26. What is the purpose of performing a sieve analysis on aggregates? → To determine particle size distribution.
27. According to ASTM C702, when performing mechanical splitting, what action should be taken if material bridges across the chutes of the splitter? → Stop the process, clear the bridge, and re-run the material through
28. Which of the following situations represents 'biased sampling' of aggregate? → Consistently sampling only from the outside edges of a stockpile where fines accumulate
29. When sampling aggregate from a barge or ship hold, what is the recommended approach if material cannot be sampled from a flowing stream? → Sample from multiple locations within the hold at varying depths
30. After washing, the retained aggregate must be dried to a constant mass at what temperature range? → 110 ± 5°C (230 ± 9°F)