Formwork basics
Forms must be strong enough to resist the fluid pressure of concrete, which is roughly 150 pounds per cubic foot. Brace forms with kickers and walers, and stake them firmly. Failed forms during a pour are dangerous and expensive.
Rebar fundamentals
Reinforcing steel resists tension. Size is given in eighths of an inch: number 4 bar is half-inch diameter. Lap splices are typically 40 bar diameters. Maintain proper cover from the surface, generally 3 inches for concrete cast against earth and 1.5 to 2 inches for formed concrete.
Placement and finishing
Pour into the forms, do not drop from too high, and consolidate with a vibrator to remove air pockets. Strike off, bull float, and let bleed water evaporate before final finishing. Cure for at least seven days by keeping the surface wet or covered.
Mini-quiz
Attempt 1 · 3 questions
Check your understanding. Passing is 70% — but you can keep going to the next lesson either way.
Question 1
Based on "Formwork basics", which statement is correct?
Question 2
Based on "Rebar fundamentals", which statement is correct?
Question 3
Based on "Rebar fundamentals", which statement is correct?