ARCC 2202 Lecture Notes - Lecture 8: Shear And Moment Diagram, Fly Ash, Vapor Barrier
16 Dec 2016
School
Department
Course
Professor
Lecture Eight
Concrete
Recycled Material
Fly ash, also known as "pulverized fuel ash" in the United Kingdom, is one of the residues
generated by coal combustion, and is composed of the ļ¬ne particles that are driven out of the
boiler with the ļ¬ue gases. Can be used to displace cement.
Recycled concrete: Crushed concrete can be used to replace aggregate
Moment diagrams of a steel beam
CONCRETE FUNDAMENTALS:
ā¢basic ratio: 1 cement, 2 sand, 3 gravel
ā¢water - cement ratio: kept below 60% of weight of cement
ā¢too much water will create a defect
ā¢slump test is used for testing of ratio
ā¢aggregate must be small enough to pass through small rebar
*about 28 days for concrete to cure fully
ā¢!burlap commonly used to keep the cement wet
ā¢ļ¬y ash also known as āpulverized fuel ashā
ā¢ļ¬rst time used?
ā¢the efļ¬ciency tower, has a RC foundation for the massive structure
find more resources at oneclass.com
find more resources at oneclass.com
ā¢Concerete beam reinforcement
ā¢must be at the top and bottom (tension and compressions parts)
ā¢bending moment diagramā¢ā¢
ā¢given branding moment diagramā¢ā¢
Installing a proper concrete slab
a)āÆInstall slab edge to supporting stakes
b)āÆSlab section ready to pour with vapour barrier, welded wire fabric reinforcing, and edge forms
in place
c)āÆAsphalt impregnated ļ¬bre board forms a control joint
d)āÆStriking off the surface of the slab
e)āÆBull ļ¬oat for preliminary smoothing
f)āÆHand ļ¬oating brings cement paste to the surface
g)āÆFloating can be done by machine
h)āÆSteel troweling after ļ¬oating produces a dense hard smooth surface
i)āÆFinished section of concrete slab ready for curing
j)āÆOne method for damp curing a slab: cover it with polyethylene sheeting
One Way Slabs
Depths are typically 100 - 250mm (4-10ā). The most economical beam is one whose depth is 2
or 3 times the breadth.
However, one way slabs are often supported by beams that are several times as broad as they
are deep, called slab bands.
Advantages: the width of the band reduces the span of the slab resulting in a reduced thickness,
the reduced depth allows for a reduction in ļ¬oor to ļ¬oor height resulting in economies from
reductions in cladding, partitions, vertical ductwork etc.
Two Way Slabs
Two-way ļ¬at slab are generally more economical where the columns can be spaced in bays that
are nearly square.
find more resources at oneclass.com
find more resources at oneclass.com
