Chapter 10 Flashcards
The single most important factor in determining the ultimate strength of concrete is?
The water to cement ratio
Hardening of concrete involves a chemical process known as_____, in which water combines with the particles of cement to form a microscopic gel
Hydration
During the hardening of concrete, heat is given off by the chemical process
Heat of hydration
Quality control of concrete:
Normal design strength is reached?
After 28 days
Concrete in the process of curing must be maintained at the correct temperature, ideally between?
50 and 70°F
Concrete cured at or above 100°F will not reach its proper strength
Collapse of precast concrete:
Prestressed concrete systems may be more vulnerable to failure than ordinary reinforced concrete. The systems use reinforcing cables and rods made of high-strength steel’s that can yield at temperatures as low as?
752 degrees Fahrenheit
Ordinary reinforcing:
Concrete beams are frequently cast in the shape of a?
Tee
The primary function of placing reinforcing steel and concrete is too?
Resist tensile forces
Ordinary reinforced:
The steel can also be used to support some of the compressive forces. Vertical reinforcing bars are known as___and are provided to resist the?
Stirrups
Diagonal tension
Concrete framing systems:
The simplest and most economical floor system
Flat plate
Plain floor slab about 8 inches thick that rest on columns spaced up to 22 feet apart and depends on diagonal and orthogonal patterns of reinforcing bars for structural support because the slab lacks beams
Flat plate
A simple system that consist of a concrete slab with concrete columns for support
Flat slab concrete frame
Flat slab concrete frame:
The slab of concrete ranges and thickness from_to_.
6-12”
Flat slab concrete plate:
In a building that will support heavy live loads, the area around the columns is reinforced with additional concrete in the form of?
Drop panels or mushroom capitals
Flat slab concrete frame:
If the building will support light loads, this additional reinforcing is not necessary. The system is the known as a?
Flat plate
Slab and beam framing:
The spacing often gives an appearance similar to wood joist and is sometimes referred to as?
Concrete joist construction
Slabs in this type of construction can be as thin as 2 inches.
Slab and beam framing
Consist of a concrete slab supported by concrete beams
Slab and beam framing
Slab and beam framing:
When the concrete beams run mainly in one direction, the framing is known as a?
One way reinforced slab
This design provides a thicker slab while illuminating the weight of unnecessary concrete in the bottom half of the slab
Waffle construction
Slab and beam concrete framing featuring concrete beams running into directions is known as?
Two way slab construction
*waffle construction
This construction is used where spans are short and floor loading are high
Warfel construction, two-way framing SYSTEM
Reinforcing steel placed in the bottom of the formwork provides reinforcement in two directions
Waffle construction
Structural steel beams can replace concrete beams to support a poured concrete slab.
Concrete plus structural steel
Other precast components are cast at the site and moved into position
Tilts up panels.
Precast concrete
A major disadvantage to using precast concrete is the need to?
Transport the finished components to the job site
Advantages to using precast concrete include:
Higher degree of quality control possible. Work can proceed more quickly at the job site. Precast concrete sandwich panels can be produced using a poly steering core to improve insulating properties of the precast concrete
Precast concrete slabs for floor systems can be cast in standard shapes that include:
Solid slabs, hollow core slabs, single T slabs, and double T slabs
Precast concrete slabs:
Solid slabs are used for short spans up to approximately?
The tea slabs can be use for spans up to?
30ft
120ft
This style of construction requires that the roof assembly maintain structural integrity. Failure of the roof can result in failure of the wall from outward horizontal forces
Tilt up construction
Reinforced wall panels are cast at the job site in horizontal casting beds
Tilt up construction
Type of construction and which concrete wall sections are cast on the concrete floor of the building in tilted up into the vertical position
Tell Top construction. Also known as tilt slab construction
Precast connections:
Supports for precast beams may include___ cast into the columns
Korbels, brackets)
Several methods of reinforcing concrete include:
Ordinary reinforcing and prestressing
