Field technicians fill plastic molds from a sample of the load, rod them in layers and leave them on site at 60 to 80 F for up to 48 hours before they go to the lab for moist curing. Standard-cured cylinders decide whether the concrete met the spec, while field-cured cylinders kept beside the structure show when it is safe to strip, stress or load. A set is commonly four to six cylinders, broken at 7 and 28 days with spares held back.
Make a set of six cylinders off truck 12 and leave them in the cure box, not in the sun on the tailgate.
Cylinders left in the sun, knocked over or bounced around loose in a truck bed break low, and a low break still costs days of arguing.
Also heard as
- cylinders
- test cylinder
- specimen
- cyl
Related terms
Break
A cylinder strength test result, or the crushing of cylinders in the lab.
Compressive strength
The crushing load concrete can carry per unit area, the main property specified and tested for concrete.
f'c
Symbol for specified compressive strength, the design strength the engineer requires, usually at 28 days.
Core
A cylinder of hardened concrete drilled out of a structure to test its strength or inspect its condition.