Hardened Concrete
Properties
Hardened Concrete
Properties
It is important for the engineer to
understand the basic properties of hardened
concrete and be able to evaluate these
properties.
The main properties of hardened concrete
are compression strength, tensile/bending
strength, durability strength, permeability,
Resistant to weather and chemical reaction,
deformation, shrinkage, creeping and fire
resistant
1)Compressive Strength
Compressive strength is the capacity of a
material or structure to withstand axially
directed pushing forces
Measured in Mega Pascal(Mpa) or kn/mm²
Compressive strength is one of the main
structural design requirement to ensure the
concrete structure will able to carry the
intended load
Compressive strength test
Tensile and flexural strength
It is the ability of a concrete to resist failure
in tensile and flexural
Also measured in Mega Pascal(Mpa) or
kn/mm²
Concrete are weak in tensile strength
Tensile strength of a concrete usually is
1/10 from its compressive strength
flexural strength test
Durability Strength
Resistance to weathering, chemical,
freezing and fire attack.
Depends a lot on the density of concrete
Concrete cover thickness affect the
durability properties.
Resulting crack and rebar Corrosion
Permeability
Permeability is an important factor that
largely affects the durability of hardened
concrete.
Permeable concrete allows water and
chemical to penetrate and attacks the
concrete and reinforcement steel.
Resistant to weather and
chemical reaction
Concrete can be exposed to weather and
chemical attacks within time.
Concrete structure especially located at food
process industries such as vinegar factories
are exposed to chemical attack.
Dense concrete have high ability to
withstand chemical and weather attack
Deformation ( ubah bentuk)
Concrete like the other material is exposed to expansion
and contraction due to weather changes
Concrete will expand when it is wet or the temperature is
in cold and high humidity
Concrete will shrink/contract when it dries or the
temperature is high
Concrete is also exposed to warping due to weather
changes.
Creep ( keterikan)
Creep is defined as the gradual increases in
strain within time under sustained load
Creep of concrete is a long term process and
it takes places over many years.
Creep in Concrete
Creep in Concrete
water
Creep
Consequences of creep
Loss in pre-stress
possibility of excessive deflection
stressing of non load bearing members
Fire Resistant
Concrete has a high degree of fire resistance and,
in the majority of applications, can be described as
fireproof when properly designed. Concrete is a
very effective fire shield. The mass of concrete
confers
a high heat storage capacity. Also its porous
structure provides a low rate of temperature rise
across a section.
These properties result in a low rate of
temperature rise that enables concrete to act as an
effective fire shield.
Fire Resistant