ACI Aggregate Testing Technician Level 1

Which ASTM standard covers the sampling of aggregates in the field for testing purposes?

• AASTM D75
• BASTM C136
• CASTM C702
• DASTM C127

According to ASTM D75, what is the minimum mass of a sample of coarse aggregate with a nominal maximum size of 1 in. (25.0 mm) for sieve analysis?

• A10 kg (25 lb)
• B2 kg (5 lb)
• C25 kg (55 lb)
• D50 kg (110 lb)

When sampling aggregate from a stockpile, ASTM D75 recommends taking increments from which locations?

• ATop third, midpoint, and bottom third of the stockpile
• BOnly from the top of the stockpile where segregation is minimal
• COnly from the base where fines accumulate
• DFrom a single location near the middle height

When sampling aggregate from a conveyor belt per ASTM D75, the belt should be:

• AStopped before removing all material between two templates
• BRunning at full speed while scooping material
• CSlowed to 50% speed for safe sampling
• DRunning in reverse to concentrate fines

Per ASTM D75, what is the minimum number of increments that must be combined to form a field sample of fine aggregate from a flowing stream?

• AAt least 3 increments
• BExactly 1 increment
• CAt least 10 increments
• D2 increments

According to ASTM D75, the minimum field sample mass for a fine aggregate to be used for sieve analysis and fineness modulus is:

• A10 kg (25 lb)
• B1 kg (2 lb)
• C25 kg (55 lb)
• D50 kg (110 lb)

In aggregate specifications, nominal maximum aggregate size (NMAS) is generally defined in terms of what?

• AThe smallest sieve opening through which 100% of the aggregate passes
• BThe largest sieve that allows some particles to be retained
• CThe smallest sieve that allows all particles to pass without retention
• DThe sieve on which 50% of the aggregate is retained

If a stockpile has a nominal maximum aggregate size of 37.5 mm (1-1/2 in.), what is the minimum required field sample mass per ASTM D75?

• A75 kg (165 lb)
• B10 kg (25 lb)
• C25 kg (55 lb)
• D15 kg (35 lb)

Which container or device is commonly used to transport aggregate samples from the field to the lab to prevent loss of moisture?

• ASealed moisture-proof container or heavy-duty bag
• BOpen mesh sack
• CPerforated metal pan
• DOpen cardboard box

What is the primary purpose of obtaining a representative aggregate sample per ASTM D75?

• ATo ensure lab test results reflect the true properties of the material being evaluated
• BTo satisfy paperwork requirements for the project
• CTo make sieve analysis faster
• DTo reduce the cost of testing

Which ASTM standard covers the procedure for reducing field samples of aggregate to the size required for testing?

• AASTM C702
• BASTM D75
• CASTM C136
• DASTM C128

ASTM C702 Method A requires the use of which device to split an aggregate sample?

• AA mechanical sample splitter (riffle splitter) with equal-width chutes
• BA rotary concrete mixer
• CA sieve shaker
• DA specific gravity basket

According to ASTM C702, a riffle splitter used for coarse aggregate must have how many chutes as a minimum?

• A8 chutes
• B4 chutes
• C12 chutes
• D16 chutes

Per ASTM C702, a mechanical splitter for fine aggregate requires a minimum of how many chutes?

• A12 chutes
• B6 chutes
• C8 chutes
• D20 chutes

Per ASTM C702, the chute width of a mechanical splitter must be at least how much larger than the largest particle in the sample?

• A50% larger (approximately 1.5 times the largest particle)
• BEqual to the largest particle
• C2 times the smallest particle
• D10% larger

ASTM C702 Method B (quartering) is performed by:

• AMixing the sample, coning it on a clean flat surface, flattening the cone, dividing into…
• BSplitting the sample on a mechanical riffle splitter with no manual intervention
• CPouring half the sample into a funnel and keeping the other half
• DWeighing the sample and cutting the pile in half with a shovel

ASTM C702 Method C (miniature stockpile) is permitted only for:

• ADamp fine aggregate
• BDry fine aggregate
• COven-dry coarse aggregate
• DAny aggregate regardless of moisture

Why is it important to thoroughly mix an aggregate sample before reducing it by quartering per ASTM C702?

• ATo prevent bias from segregation so each quarter contains a representative gradation
• BTo break down larger particles
• CTo remove dust from the sample
• DTo dry the sample quickly

For reducing a dry fine aggregate sample per ASTM C702, which methods are permitted?

• AMethod A (mechanical splitter) or Method B (quartering)
• BMethod C (miniature stockpile) only
• CMethod A only
• DAny method including miniature stockpile

Which ASTM standard specifies the procedure for sieve analysis of fine and coarse aggregates?

• AASTM C136
• BASTM C117
• CASTM C127
• DASTM D75

Fineness modulus (FM) of a fine aggregate is calculated as:

• AThe sum of the cumulative percentages retained on the standard sieves (No. 100, No. 50, N…
• BThe sum of percent passing each sieve divided by 100
• CThe weight retained on the No. 200 sieve divided by 100
• DThe sum of percent retained on all sieves including the pan divided by 100

Per ASTM C33, what is the acceptable range of fineness modulus for fine aggregate used in concrete?

• A2.3 to 3.1
• B1.5 to 2.0
• C3.5 to 4.5
• D0.5 to 1.5

A fine aggregate sieve analysis shows cumulative percent retained of 0, 5, 15, 35, 60, 80, and 95 on the 3/8 in., No. 4, No. 8, No. 16, No. 30, No. 50, and No. 100 sieves respectively. What is the fineness modulus?

• A2.90
• B2.50
• C3.10
• D2.00

Per ASTM C136, for a fine aggregate sample, what is the minimum mass of the test sample after drying?

• A300 g
• B100 g
• C500 g
• D1000 g

According to ASTM C136, after sieving is complete, the total mass of material retained on all sieves (including the pan) must agree with the original dry mass of the sample within what tolerance?

• A0.3%
• B0.1%
• C1.0%
• D5.0%

During a sieve analysis, what is the primary reason for agitating the sieves for a sufficient period?

• ATo ensure that all particles that can pass a sieve opening have had an opportunity to pass
• BTo physically break down oversized particles
• CTo heat the sample and drive off moisture
• DTo polish the sieve screens

In ASTM C136, what is the maximum allowable mass retained on any single sieve to avoid overloading and ensure accurate sieving?

• AA mass corresponding to a maximum of 4 kg/m² for sieves with openings 4.75 mm and smaller…
• BA mass of 1 kg per sieve regardless of opening size
• CWhatever mass fits in the sieve frame without spilling
• DA mass equal to 50% of the original sample

Which sieves are typically used in the sieve analysis of fine aggregate for concrete per ASTM C136?

• A3/8 in., No. 4, No. 8, No. 16, No. 30, No. 50, No. 100, and the pan
• B1 in., 3/4 in., 1/2 in., 3/8 in., No. 4, and pan
• CNo. 4, No. 10, No. 40, No. 100, and No. 200
• D3 in., 2 in., 1 in., 1/2 in., and pan

What does the term 'cumulative percent retained' mean in a sieve analysis?

• AThe running total of percent retained on the current sieve plus all coarser sieves above…
• BThe mass retained on each individual sieve
• CThe percent of the sample that passes through the smallest sieve
• DThe percent loss during sieving

ASTM C136 requires that fine aggregate be sieved until not more than what percentage by mass passes any sieve during 1 minute of continuous hand sieving?

• A1%
• B0.1%
• C5%
• D10%

A fine aggregate sample has the following cumulative percent retained values: 0 on 3/8 in., 2 on No. 4, 15 on No. 8, 30 on No. 16, 50 on No. 30, 78 on No. 50, and 95 on No. 100. What is the fineness modulus?

• A2.70
• B2.50
• C2.90
• D3.05

Why must an aggregate sample be dried before running a sieve analysis per ASTM C136?

• AMoisture causes particles to stick together, blocking sieve openings and producing an ina…
• BWet particles weigh more, which changes the fineness modulus
• CSieves rust if exposed to wet material
• DMoist aggregate cannot be measured on a scale

What does a 'well-graded' aggregate gradation curve look like on a semi-log sieve analysis plot?

• AA smooth, continuous curve with a good distribution of particles across all sieve sizes
• BA flat horizontal line at 50% passing
• CA vertical line at one particle size
• DA gap in the middle with high values at both ends

When computing the percent retained on each sieve in a fine aggregate sieve analysis, the calculation is based on:

• AThe original dry mass of the test sample
• BThe mass retained on the No. 200 sieve only
• CThe sum of masses on the coarse sieves only
• DThe wet mass of the sample before drying

Per ASTM C136, the test sieves used for the analysis must conform to which standard?

• AASTM E11 (Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves)
• BASTM C33
• CASTM C150
• DASTM C125

Which ASTM standard is used to determine the amount of material finer than the 75 μm (No. 200) sieve in aggregate by washing?

• AASTM C117
• BASTM C136
• CASTM C127
• DASTM C566

In ASTM C117, the percentage of material finer than the 75 μm (No. 200) sieve is calculated using which formula?

• AA = ((B − C) / B) × 100, where B = original dry mass and C = dry mass after washing
• BA = (C / B) × 100
• CA = (B − C) × 100
• DA = (B + C) / 2

During ASTM C117, what is placed above the No. 200 sieve to protect it during washing?

• AA No. 16 (1.18 mm) sieve
• BNothing — water is poured directly on the No. 200
• CA No. 4 (4.75 mm) sieve
• DA No. 8 (2.36 mm) sieve