COSC 354 EXAM 2 QUESTIONS & ANSWERS
Properties of Concrete - Answer -60-80% aggregate
10-15% portland cement
20% water
Remaining is air
Aggregates in Concrete - Answer -Coarse gravel
Fine sand or crushed stone
75% of the volume
Size of the aggregate determines the workability, strength, durability, and finish.
Well Graded - Answer -A soil that displays a good representation of all particle sizes.
For instance, well-graded sand will contain a fairly even distribution of coarse, medium,
and fine sand.
Poorly Graded - Answer -A soil that does not contain a good representation of all
particle sizes. A poorly graded soil may contain a narrow range of particle sizes
(uniformly graded) or may not contain one or more ranges of particle sizes (gap
graded).
Gap Graded - Answer -only limited sizes; good interlock; low permeability
Portland Cement - Answer -Mixture of limestone, cement rock, shale, and clay
Clinker - Answer -Solid material of limestone that are even heat to kiln
Supplementary Materials in Concrete - Answer -Pozzolans
Fly ash (coal)
Slag (welding)
Clay and shales (organic)
Concrete Admixtures - Answer --Air-entraining admixtures (freeze resistance)
-Water-reducing admixtures (less water required)
-Accelerating admixtures (helps cure in cold)
-Retarding admixtures (helps cure in heat)
-Workability admixtures
-Shrinkage-reducing
-Corrosion inhibiting
-Freeze protection
-Coloring agents
Water in Concrete - Answer -water is and active material used to bind the cement
mixture with a aggregate.
, water used in the concrete mixture should be fit for drinking without any organic
compound.
Water Cement Ratio - Answer -.4-.6
Heat of Hydration - Answer -the enthalpy change that occurs when 1 mol of the
gaseous solute ions is dissolved in water
Hydration Process - Answer -H2O sticks to the outer elements in the rock. Results in a
softening effect
Concrete Testing - Answer -Done by a 3rd party
Slump test measures the consistency of a concrete batch to see how it will flow
Rebar in Concrete - Answer -Concrete is weak in tension, so the rebar makes up for
that
Rebar Materials - Answer -Black bar is most used, can corrode easily
Epoxy coated, resistant to corrosion and used in coastal areas
Galvanized, more expensive than epoxy
Stainless steel, easily bent in the field
Glass fiber reinforced polymer, complete resistance to corrosion, 10x expensive than
epoxy coated
Types of Steel - Answer -S - Carbon Steel (black steel)
A - Axle Steel
W - Low Alloy Steel
SS - Stainless Steel
CS - Low Carbon Chromium
Rebar Markings - Answer -N - Letter of symbol of production mill
6 - Bar Size
S - Type of Steel
60 - Grade mark in KSI, so 60 KSI is 60,000 PSI
Pretension - Answer -Steel stretched before concrete is placed
Posttension - Answer -Tendons are tensioned after concrete has hardened
Slab on Grade - Answer -Minimal site prep
Formwork
Capillary Break
Vapor Retarder
Reinforcement
Concrete
Properties of Concrete - Answer -60-80% aggregate
10-15% portland cement
20% water
Remaining is air
Aggregates in Concrete - Answer -Coarse gravel
Fine sand or crushed stone
75% of the volume
Size of the aggregate determines the workability, strength, durability, and finish.
Well Graded - Answer -A soil that displays a good representation of all particle sizes.
For instance, well-graded sand will contain a fairly even distribution of coarse, medium,
and fine sand.
Poorly Graded - Answer -A soil that does not contain a good representation of all
particle sizes. A poorly graded soil may contain a narrow range of particle sizes
(uniformly graded) or may not contain one or more ranges of particle sizes (gap
graded).
Gap Graded - Answer -only limited sizes; good interlock; low permeability
Portland Cement - Answer -Mixture of limestone, cement rock, shale, and clay
Clinker - Answer -Solid material of limestone that are even heat to kiln
Supplementary Materials in Concrete - Answer -Pozzolans
Fly ash (coal)
Slag (welding)
Clay and shales (organic)
Concrete Admixtures - Answer --Air-entraining admixtures (freeze resistance)
-Water-reducing admixtures (less water required)
-Accelerating admixtures (helps cure in cold)
-Retarding admixtures (helps cure in heat)
-Workability admixtures
-Shrinkage-reducing
-Corrosion inhibiting
-Freeze protection
-Coloring agents
Water in Concrete - Answer -water is and active material used to bind the cement
mixture with a aggregate.
, water used in the concrete mixture should be fit for drinking without any organic
compound.
Water Cement Ratio - Answer -.4-.6
Heat of Hydration - Answer -the enthalpy change that occurs when 1 mol of the
gaseous solute ions is dissolved in water
Hydration Process - Answer -H2O sticks to the outer elements in the rock. Results in a
softening effect
Concrete Testing - Answer -Done by a 3rd party
Slump test measures the consistency of a concrete batch to see how it will flow
Rebar in Concrete - Answer -Concrete is weak in tension, so the rebar makes up for
that
Rebar Materials - Answer -Black bar is most used, can corrode easily
Epoxy coated, resistant to corrosion and used in coastal areas
Galvanized, more expensive than epoxy
Stainless steel, easily bent in the field
Glass fiber reinforced polymer, complete resistance to corrosion, 10x expensive than
epoxy coated
Types of Steel - Answer -S - Carbon Steel (black steel)
A - Axle Steel
W - Low Alloy Steel
SS - Stainless Steel
CS - Low Carbon Chromium
Rebar Markings - Answer -N - Letter of symbol of production mill
6 - Bar Size
S - Type of Steel
60 - Grade mark in KSI, so 60 KSI is 60,000 PSI
Pretension - Answer -Steel stretched before concrete is placed
Posttension - Answer -Tendons are tensioned after concrete has hardened
Slab on Grade - Answer -Minimal site prep
Formwork
Capillary Break
Vapor Retarder
Reinforcement
Concrete
