Aggregates 2.0 (grading)

Types of gradations
- Uniformly graded
- Few points of contact
- Poor interlock
- High Permeability
- Well graded
- Good interlock
- Low permeability
- Gap graded
- Only limited sizes
- Good interlock
- Low Permeability
Angular shape with rough texture

Improved inter particle friction, stability and bond with binder - better for case course and asphalt concrete - but harder to work into place (i.e consolidate)
Round shape with smooth surfaces

Easier to work into shape and require less water in PC concrete
Aggregate particle sizes ranges typically from

<150 microns to >20 mm
Single sized aggregate results in

Large voids
gap graded

Smaller particles reduce void size
Reducing past content of concrete leads to :
- Reduced cost
- Reduced temperature rise
- Reduced shrinkage
- Reduced permeability
Gradation affects properties such as
- Stiffness
- Durability
- Workability
- resistance to moisture damage
- Permeability
- Fatigue resistance
Sieve maximum size

Is the smallest sieve through which the entire sample passes
Nominal maximum size
- is the standard sieve opening immediately smaller than the smallest through which all aggregate passes
- must retain less than 10% of the sample

Author

Marciaho

269653

Card Set

Aggregates 2.0 (grading)

Description

Aggregates 2.0 (grading)

Updated

2014-04-07T22:53:01Z

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