ATT Bulk Density, Voids & Organic Impurities 3

Question 1

Which ASTM standard governs the Organic Impurities in Fine Aggregates for Concrete test?

Accepted Answer

ASTM C40

Answer

ASTM C40 is the standard test method for organic impurities in fine aggregates for concrete.

Question 2

In the ASTM C29 jigging method, how many times is each side of the measure raised and dropped per layer?

Accepted Answer

50 times

Answer

The jigging method requires each side of the measure to be raised approximately 50 mm (2 in) and dropped 50 times per layer.

Question 3

If the liquid color in an ASTM C40 test is lighter than the reference standard, what does this indicate?

Accepted Answer

The aggregate likely has acceptable organic impurity levels

Answer

A color lighter than Organic Plate No. 3 indicates the fine aggregate likely does not contain harmful levels of organic impurities.

Question 4

The reference color in the ASTM C40 organic impurities test is equivalent to Gardner Color Standard No.:

Accepted Answer

11

Answer

Organic Plate No. 3 (the reference standard for ASTM C40) is equivalent to Gardner Color Standard No. 11.

Question 5

What is the diameter of the tamping rod specified in ASTM C29?

Accepted Answer

16 mm (5/8 in)

Answer

ASTM C29 specifies a smooth, straight steel tamping rod 16 mm (5/8 in) in diameter and approximately 600 mm (24 in) in length.

(ATT) ACI Aggregate Testing Technician Practice Test