Engineering Materials
Civil-engineering materials include concrete, steel, aggregates, and wood. The exam tests mix design, material properties, reinforcement, and quality tests that confirm materials meet specification.
Concrete Mix Design
By Abrams' law, a lower water-cement ratio produces higher compressive strength, because excess water leaves capillary voids in the hardened paste. Water-reducing admixtures maintain workability at low water-cement ratios. Strength is verified by cylinder-break tests at 28 days.
Reinforcing Steel
U.S. rebar sizes give the nominal diameter in eighths of an inch: a #8 bar is 1.0 in, a #4 bar is 0.5 in. Grade 60 reinforcement yields at 60 ksi. Reinforcement provides tensile capacity that concrete alone lacks.
Quality Control Tests
The slump test measures the workability (consistency) of fresh concrete, not its strength. Other tests cover air content, aggregate gradation, and soil compaction (Proctor). Material test methods confirm specification conformance before and during placement.