2. Portland
CementPortland cement (often referred to
as OPC, from Ordinary Portland Cement) is the
most common type of cement in general use
around the world, used as a basic ingredient
of concrete, mortar, stucco, and most non-
specialty grout.
3. What makes up Portland Cement?
Cement CCN Mass %
Calcium oxide, CaO C 61–67%
Silicon dioxide, SiO2 S 19–23%
Aluminum oxide,
Al2O3
A 2.5–6%
Ferric oxide, Fe2O3 F 0–6%
Sulfate 1.5–4.5%
•Portland cement is primarily made of lime and silica,
which account for about 85 percent of its weight.
•The rest of the cement is made up of iron, aluminum,
calcium and silicon, as well as trace amounts of other
ingredients.
•Gypsum is added as well to control the amount of time
it takes to set.
limestone
silica
4. Types of Portland Cement:
There are five basic types of portland cement.
•Type I is a general-purpose blend used when there are no
issues requiring specific concretes.
•Type II is used in high-sulfate conditions. Sulfates can damage
concrete, and Type II portland cement resists this damage.
• Type III offers a higher degree of strength early in the setting
process.
•Type IV is formulated to have the setting properties required
for building massive structures.
•Type V is for high sulfate resistance.
5. •The behavior of concrete pavement which is subject to loading
and environmental effect entirely depends upon the quality of the
concrete and underlying sub-grade and base course.
•Concrete, like other materials also expand when wetted and
contracts when dried. It shrinks after pouring as the mortar
hardens when the cement hydrates.
hot cold
6. 1. That, the pavement slab is designed as beams of plain concrete.
2. That, transverse cracking of concrete slab cannot be avoided. The designer
presumed that cracks could be controlled by providing reinforcement to slab
joints with the following assumptions:
a. With reinforcement, cracks on the slab will be confined to a weakened plain
joints spaced at 4.50m to 6.00m distance.
b. Vertical offsetting across the narrow cracks will be prevented by aggregate
interlock, or by the dowel bars.
c. with simply reinforced slab, cracks will only appear at weakened plane joints
spaced at 12 to 20m intervals. Hair cracks to be held tightly by the steel
between joints.
d. With continuous reinforcement, transverse joints are omitted, hair cracks
are checked by the steel and developed at close intervals.
e. Faulting is counteracted by aggregate interlock and steel bars.
7. 3. Longitudinal cracking of slabs more than one lane wide is also
inevitable.
Deterioration of Concrete
Pavement- is due to stresses brought about
by load, moisture and temperature.
Distress of Concrete- it is generally
grouped into the following categories:
•Distortion- is a vertical displacement of
concrete slab at the joints or cracks, this
is due to failure or weakness of concrete
joints.
•Cracking- can take many forms in
concrete pavements which could be a
result of either: from applied load or
from temperature or moisture changes.
•Disintegration- appears in the form of
durability cracking, scaling or spalling as
result of mix design or construction
related problems.
8.
9. If you require paving services, you probably already know that you have two
choices: concrete or asphalt. So which of the two is the best choice?
Physical Differences Between Concrete and Asphalt
•Hot mix asphalt is made of
aggregates (stone, sand, gravel)
and liquid asphalt, the oil-based
glue which is the glue that holds
everything together.
•Concrete is made from
American materials such as
limestone, rock and
water. Concrete is also the
most-used manmade material
in the world.
10. Safety Differences Between Paving with
Concrete or Asphalt
•Areas paved with asphalt require more
maintenance than those paved with
concrete. As a result, there is more need
for repair crews to handle maintenance
of asphalt streets and parking lots. This
means more congestion and disruption
to work areas, and more danger to road
crews and drivers alike.
.
•Rigid concrete is also more
durable than asphalt. This
means that streets paved with
concrete are less likely to have
potholes. The surface of
concrete is also better at
preventing automobile skidding,
keeping drivers and their
families safe.
11. Cost Differences of Building &
Maintenance of Paving Materials
Concrete pavement's life can range anywhere
from 20-40 years. But when you factor in
annual maintenance, asphalt pavement can
cost four to seven times as much money to
maintain. This saves you long-term on repair
and maintenance.
12. Noise reduction
Use of asphalt road surfaces can
significantly reduce noise both inside
and outside the car, helping to
prevent accidents by alleviating a
source of stress that contributes to
driver fatigue.
13. •Concrete is 100% recyclable, and
the most recycled construction
material in the world. So rather than
ending up in your state's landfills, it
can be broken down and used in
new pavement, or for other
construction purposes.
•Asphalt is 100% recyclable and is
routinely milled and re-laid along
with fresh materials, saving money
and preserving non-renewable
natural resources. Recycling also
reduces the use of virgin quality
gravel, preserves landfill and saves
transport.
