ACI MFTT flashcards
ACI MFTT · 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.
- Mortar Type M
- Highest-strength mortar in ASTM C270; used for reinforced masonry and severe exposures; minimum 28-day compressive strength is 2500 psi.
- Mortar Type S
- Medium-high strength mortar in ASTM C270; minimum 28-day compressive strength 1800 psi; suitable for normal reinforced masonry.
- Mortar Type N
- General-purpose mortar in ASTM C270; minimum 28-day compressive strength 750 psi; common for above-grade nonreinforced exterior walls.
- Mortar Type O
- Low-strength mortar in ASTM C270; minimum 28-day compressive strength 350 psi; used for nonload-bearing interior partition walls.
- ASTM C270
- Standard specification for mortar for unit masonry; defines mortar types by proportion and minimum 28-day compressive strength.
- ASTM C90
- Standard specification for load-bearing concrete masonry units; covers materials, dimensions, and strength requirements for hollow and solid units.
- Grout sampling
- Fresh grout is sampled per ASTM C1019 from the mixer or pump discharge before placement, then molded into test specimens.
- Flow table test
- ASTM C1437 consistency test; mortar is placed in a mold, dropped 25 times in 15 seconds, and spread is measured.
- Flow formula
- Flow (%) = [(spread diameter minus original diameter) / original diameter] x 100; average four measured diameters.
- Mortar water content
- Determined by drying a weighed fresh mortar sample to constant mass; water content compares mass loss with dry mass.
- Mortar cube specimen
- Field mortar compressive strength is commonly evaluated with 2-inch cubes molded per ASTM C780 and cured to test age.
- Grout specimen
- ASTM C1019 grout specimens are molded from fresh grout, consolidated, cured, and tested in compression at the specified age.
- Specimen identification
- Each field specimen must be marked with project, location, batch, date, and test age before curing.
- Initial curing
- Field specimens must be protected from moisture loss, vibration, and temperature extremes during initial curing.
- Masonry prism
- A small assemblage of units, mortar, and grout built to represent masonry and tested in compression per ASTM C1314.
- Prism test set
- A set typically contains at least three prisms; the average strength is used to evaluate the masonry.
- Prism construction
- Prisms must use the same units, mortar, grout, and joint construction as the masonry they represent.
- Height-to-thickness ratio
- Prism strength is corrected for h/t ratio because short prisms give higher apparent strength; C1314 gives correction factors.
- Prism capping
- Caps must be plane, parallel, and perpendicular to the load; sulfur or gypsum caps are commonly used.
- Prism compressive strength
- Computed as maximum load divided by the specified cross-sectional area; report average, individual values, and age.
- Prism curing
- Prisms are cured under conditions representative of the field masonry before capping and testing at the specified age.
- ASTM C140
- Standard test methods for sampling and testing concrete masonry units, including compressive strength, absorption, and saturation.
- Unit compressive strength
- Maximum load on a capped unit loaded perpendicular to the bed divided by gross cross-sectional area.
- Absorption formula
- Absorption (%) = [(saturated mass minus oven-dry mass) / oven-dry mass] x 100 for the specified immersion period.
- Saturation coefficient
- Ratio of a unit's 24-hour cold-water absorption to its absorption after a longer saturation or boiling procedure.
- Oven-dry mass
- Unit mass after drying to constant mass at the standard temperature; it is the denominator in absorption calculations.
- Unit specimen defects
- Units with cracks, chips, or irregular geometry that affect load or absorption should be noted or excluded per the standard.
- Test report contents
- Report must identify project, sample location, test method, test date, specimen age, dimensions, results, and tester.
- ACI MFTT
- ACI Masonry Field Testing Technician certification qualifies personnel to perform specified masonry field tests under ACI requirements.
- Record retention
- Test records must be retained per contract or code and protected from loss or unauthorized alteration.
- Anomalous result
- A result that is unusual or nonconforming must be reported and investigated, not discarded without record.
- Field batch record
- Notes should include batch time, mixer, materials, water additions, and any deviation from the specified procedure.