ATT ATT Flat, Elongated Particles & Sand Equivalent 2

Question 1

Which ASTM standard governs the sand equivalent value test for coarse-grained soils and fine aggregates?

Accepted Answer

ASTM D2419

Answer

ASTM D2419 is the standard test method for sand equivalent value of soils and fine aggregate.

Question 2

In the sand equivalent test (ASTM D2419), the purpose of the flocculating solution (calcium chloride) is to:

Accepted Answer

Cause clay and fine dust to flocculate and settle into a distinct layer

Answer

The calcium chloride flocculating solution causes clay particles and fine dust to coagulate and settle, forming a clear boundary between the sand and clay layers.

Question 3

How is the sand equivalent (SE) value calculated in ASTM D2419?

Accepted Answer

SE = (Sand reading / Clay reading) × 100

Answer

Sand equivalent is calculated as (sand reading ÷ clay reading) × 100, where a higher value indicates less clay or fine dust contamination.

Question 4

A higher sand equivalent value in ASTM D2419 indicates:

Accepted Answer

Cleaner aggregate with less clay contamination

Answer

A higher sand equivalent value means a greater proportion of clean sand relative to clay fines, indicating better aggregate quality.

Question 5

In the sand equivalent test, the sample and flocculating solution are shaken and then allowed to stand for how long before taking readings?

Accepted Answer

20 minutes

Answer

After shaking, the ASTM D2419 test requires a 20-minute sedimentation period before measuring the sand and clay column heights.

(ATT) ACI Aggregate Testing Technician Practice Test

(ATT) ACI Aggregate Testing Technician Practice Test

ATT ATT Flat, Elongated Particles & Sand Equivalent 2