ACI CLTT-2 flashcards
ACI CLTT-2 · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Slump test layer count
- ASTM C143 requires filling the slump cone in three equal layers, each rodded 25 times with the standard tamping rod, before lifting and measuring the drop.
- Slump measurement precision
- The slump is the vertical difference between the top of the cone and the displaced original center of the specimen, recorded to the nearest 6 mm (1/4 in.).
- Slump test applicability limit
- ASTM C143 does not apply to concrete with slump less than 15 mm (5/8 in.) or to no-slump, nonplastic mixes, because the test cannot distinguish their consistency.
- Standard cylinder dimensions
- Standard compressive strength specimens are 150 mm diameter by 300 mm high cylinders, giving a length-to-diameter ratio of 2.0, the reference ratio for strength correction.
- Compressive strength formula
- Compressive strength equals the maximum load at failure divided by the cross-sectional area of the specimen (f = P/A), reported to the nearest 0.1 MPa or 10 psi.
- Standard moist curing temperature
- Standard cured cylinders are stored in moist conditions at 23 ± 2 °C (73.5 ± 3.5 °F) until the specified test age, commonly 28 days.
- Cylinder end capping tolerance
- Capped or ground ends must be plane within 0.05 mm and perpendicular to the axis within 0.5 degrees so that load is applied uniformly across the specimen.
- Pressure air meter calibration
- The pressure meter must be calibrated for the specific aggregate type and corrected for the aggregate's absorption, since the pressure method assumes a known aggregate volume.
- Volumetric air content method
- ASTM C173 determines air content by agitating concrete in a water-filled vessel and measuring the displaced volume, and is preferred for lightweight or porous aggregates.
- Unit weight of concrete
- Unit weight is the mass of concrete consolidated in a standard measure divided by the measure's volume, expressed in kg/m3 or lb/ft3.
- Concrete yield calculation
- Yield equals the total mass of all batched materials divided by the measured unit weight, giving the volume of concrete produced per batch.
- Concrete temperature measurement
- ASTM C1064 requires the thermometer to remain in the sample at least 2 minutes and be immersed at least 75 mm, away from the container walls.
- Flexural strength beam test
- ASTM C78 tests a beam under third-point loading; modulus of rupture equals PL divided by bd squared for the standard third-point loading arrangement.
- Trial batch slump adjustment
- If measured slump differs from target, adjust water and re-test; each 10 mm slump change corresponds roughly to a small water content change, but strength must be re-verified.
- Sampling plastic concrete
- ASTM C172 requires samples to be taken from the middle of the discharge stream, combined, and remixed before testing to represent the batch.
- Sieve stack order
- Nested sieves are arranged with the largest opening on top and the pan at the bottom, so material passes downward and is retained by the first sieve it cannot pass.
- Sieve completion criterion
- A sieve is considered finished when the mass passing it during one additional minute of shaking is less than 0.5 percent of the total sample mass.
- Fineness modulus formula
- Fineness modulus equals the sum of cumulative percent retained on the specified sieve series divided by 100; typical fine aggregate values range from 2.3 to 3.1.
- Nominal maximum size
- Nominal maximum size is the smallest sieve opening through which the entire coarse aggregate sample passes, one sieve larger than the maximum size fraction.
- Moisture content formula
- Moisture content equals wet mass minus oven-dry mass, divided by oven-dry mass, times 100, expressed as a percentage of the dry aggregate mass.
- Absorption formula
- Absorption equals saturated-surface-dry mass minus oven-dry mass, divided by oven-dry mass, times 100, representing water held in permeable aggregate pores.
- Bulk specific gravity formula
- Bulk specific gravity equals oven-dry mass divided by the difference between saturated-surface-dry mass and submerged mass, including permeable pore volume in the calculation.
- Apparent specific gravity
- Apparent specific gravity equals oven-dry mass divided by oven-dry mass minus submerged mass, excluding the permeable pores from the volume considered.
- Saturated surface-dry condition
- SSD aggregate has water-filled pores but a surface free of standing water, achieved by towel-drying fine aggregate or rolling coarse aggregate until damp without shine.
- Los Angeles abrasion loss
- Percent loss equals original mass minus final mass, divided by original mass, times 100, after the specified number of drum revolutions with steel spheres.
- Sulfate soundness test
- ASTM C88 measures percent mass loss after repeated immersion in sodium or magnesium sulfate solution and oven drying, simulating weathering; magnesium sulfate is more severe.
- Clay lumps test purpose
- ASTM C142 determines the percentage of clay lumps and friable particles that break down in water, which can reduce concrete strength and durability.
- Organic impurities test
- ASTM C40 compares the color of a sodium hydroxide solution in contact with the sand against a reference color standard to detect harmful organic material.
- Fine aggregate definition
- Fine aggregate passes the 4.75 mm (No. 4) sieve and is retained on the 75 micrometer (No. 200) sieve, typically natural sand or crushed stone fines.
- Coarse aggregate definition
- Coarse aggregate is predominantly retained on the 4.75 mm (No. 4) sieve and provides the main skeleton of the concrete mixture.
- Aggregate sample splitting
- A sample splitter or quartering reduces a bulk aggregate sample to a representative test portion, ensuring each subsample reflects the whole material.
- Oven-dry aggregate mass
- Oven-dry mass is obtained by drying the aggregate at 110 ± 5 °C to constant mass, the baseline for moisture and specific gravity calculations.