NICET CMT Concrete case studies
NICET CMT Concrete · Put your knowledge to work in context.
NICET's Concrete Construction Materials Testing program - usually written CMT-Concrete - is listed on nicet.org as one of the Civil Engineering Technology certification programs, in the same family as CMT-Asphalt, CMT-Soils, and the optional CMT-Performance Examinations. It exists for the technicians who stand at the discharge end of a mixer truck and in the curing room: the people who sample fresh concrete, run slump, air content, temperature and unit weight checks, cast and cure cylinders, break them, and then defend the numbers in a report or an acceptance meeting. The NICET CMT Concrete case studies are 5 cases and about 4,217 words.
1Sulfate Class S2 Mix Submittal That Exceeds the Maximum w/cm
A ready-mix producer submits a mix design for the strip footings of a cast-in-place retaining wall specified at f'c = 4,500 psi. The geotechnical report lists water-soluble sulfate in the soil as 0.42% by mass (about 4,200 ppm).
658 words, about 3 min2Hot-Weather Load: Site Water, Air Content, and the Discharge Clock
Truck 14 is batched at 10:05 with 8 yd³ of a 4,000 psi air-entrained mix: 600 lb/yd³ cementitious, 270 lb/yd³ of design water (w/cm 0.45), 0.75 in. nominal maximum aggregate.
908 words, about 5 min3Nonstandard Cylinders, Low Breaks, and a Superintendent Who Wants Acceptance
On a mid-rise project, a field technician molds twelve sets of 4 by 8 in. cylinders for 4,000 psi elevated slabs.
904 words, about 5 min4Moving-Average Failure, an Anomalous Cylinder Pair, and the Core Decision
Six consecutive 28-day test results (each the average of two 6 by 12 in. cylinders) are reported in test order for a 4,500 psi column mix: 4,720; 4,380; 4,610; 4,290; 4,540; 4,400 psi.
845 words, about 4 min5An Acceptance Record That Cannot Be Defended, and a Shattering Sulfur Cap
A testing laboratory's report serves as the acceptance record for a 60,000 square foot warehouse slab-on-ground. Each line shows specimen number, break date, maximum load, and psi only - no diameter, cap type, age, curing condition, or fracture type.
902 words, about 5 min