Concrete Flashcards
Portland Cement
Fine grey powder mixed into concrete to make it a cohesive solid.
Clinker
Ground constituents burned. Gypsum is added to create portland cement.
Aggregates
Course aggregate - gravel/crushed stone
Fine aggregate 0 sand
Hydration
Cement combines chemically with water to form strong crystals that bind the concrete together.
Curing
Hardening process of concrete
Air-Entraining
Air introduced into concrete mixture to make it flow better. Compromises strength.
Admixtures
Additions added to a concrete mixture to change the properties (add air, reduce water, etc…)
Slump Test
Test water content of concrete on site.
W-C Ratio
Water to cement ratio.
Formwork
Creates the shape of concrete structures and acts as support until the concrete cures.
Form Ties
Steel rod with fasteners to hold together two pieces of formwork.
Reinforcing Bars
Rebars. Used to resist tension forces in concrete.
Stirrup
Vertical steel bars that support horizontal rebars.
Post - Tensioning
Concrete not allowed to bond to steel during curing. Strands tensioned after hydraulic jack and anchored.
Pretensioning
Precast concrete… High-strength steel strands are stretched tightly between abutments in a precasting plant before concrete is cast. Concrete goes into compression and takes on a camber.
Camber
A slight, intentional initial curvature in a beam or slab.
One-way vs. Two Way Systems
One-Way System - Floor supported by single rows of beams in rectangular bays.
Two - Way System - Slab supported by square bays contained by beams that run in both directions.
Ribbed Slab
One way slab that can span the longest distance by using the weight of the concrete to resist forces instead of steel.
Waffle Slab
Plates or domes used to as formwork to create a longer span of Two-way joint.
Mushroom Column
Structural column that flares at the top to resist forces.
Slab Band
Beams that are several times as broad as they are deep. Used to support one-way solid slabs.
Slab on grade
Level, solid concrete poured on the surface of the ground to support a structure.
Float
A small platform suspended on ropes from a steel building frame to permit iron workers to work on connections.
Flying Formwork
Fabricated in long sections that are supported by metal trusses. Sections moved from one floor to the next via crane.
