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. What must be done to the calibration mass used to determine the volume of the unit weight measure? → It must be traceable to a standard and verified at appropriate intervals
2. An oven used for moisture content testing of aggregate must be checked for temperature uniformity. What tool is used to verify oven temperature? → A calibrated thermometer or thermocouple
3. Which factor can cause a moisture content test result to be erroneously HIGH when using the oven-dry method? → Oven temperature set too high, burning off chemically bound water
4. 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
5. What is the purpose of ASTM C87 in relation to organic impurities testing? → To compare mortar strength made with suspect aggregate to mortar made with clean aggregate
6. What is the maximum allowable lightweight pieces (coal and lignite) in fine aggregate per ASTM C33 for concrete subject to surface wear? → 0.5%
7. Which ASTM standard governs the specific gravity and absorption of fine aggregate? → ASTM C128
8. 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
9. Which ASTM standard covers the test method for flat particles, elongated particles, or flat and elongated particles in coarse aggregate? → ASTM D4791
10. What is the significance of the 3% concentration of the NaOH solution used in ASTM C40? → It is standardized to provide consistent and reproducible color extraction results
11. 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)
12. Which sieve must be placed beneath the No. 200 sieve to prevent damage during the ASTM C117 wash procedure? → No. 100 sieve
13. Which mineral phase in aggregate is most commonly associated with deleterious alkali-silica reactivity? → Opaline silica and volcanic glass
14. When performing the unit weight test on coarse aggregate, how many layers are used when rodding a 1/2-cubic-foot measure? → 3 layers
15. The inside diameter of the Los Angeles abrasion machine drum is approximately: → 711 mm (28 in.)
16. What is the typical maximum LA abrasion loss specified for coarse aggregate used in concrete pavement? → 40%
17. What is the purpose of washing the aggregate sample before the LA abrasion test? → To remove dust and fines that would falsely inflate the abrasion loss
18. Why is determining void content in aggregates important? → To estimate cement requirements
19. A technician notices the aggregate sample mass is still decreasing after 24 hours in the oven. Per ASTM C566, when should drying be considered complete? → When successive weighings at 2-hour intervals show less than 0.1% mass change
20. 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
21. In hot weather conditions on a job site, aggregate moisture content can change rapidly. What is the BEST practice to account for this? → Test moisture content at frequent intervals throughout the day
22. When testing for lightweight pieces per ASTM C123, the test result is expressed as: → Percentage by mass of lightweight pieces
23. An aggregate sample has an original dry mass of 5,000 g. After the LA abrasion test, 4,150 g is retained on the No. 12 sieve. What is the percent loss? → 17%
24. In the Micro-Deval test (ASTM D6928), what abrasive medium is used with the aggregate sample? → Steel balls and water
25. When sampling aggregate from a flowing discharge stream, increments should be collected: → At regular time intervals throughout the entire discharge period
26. A unit weight measure is calibrated by filling it with water at a known temperature. What property of water is used to calculate the volume of the measure? → Unit weight (density)
27. In the Los Angeles abrasion test, after rotation the aggregate is washed over which sieve to determine percent loss? → No. 12 (1.70 mm)
28. 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
29. When combining results of the ASTM C117 wash test with a dry ASTM C136 sieve analysis, how is the total percent passing the No. 200 sieve reported? → The wash test value is used as it captures more fines than dry sieving
30. 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