1. REINFORCED CEMENT
CONCRETE
SPECIFICATIONS AND ESTIMATIONS

2. INTRODUCTION
Reinforced Cement Concrete in which steel is embedded in such a
manner that the two materials act together in resisting forces. The
reinforcing steel—rods, bars, or mesh—absorbs the tensile, shear, and
sometimes the compressive stresses in a concrete structure. The
invention of reinforced concrete in the 19th century revolutionized the
construction industry, and concrete became one of the world’s most
common building materials.

3. HISTORY
François Coignet was a French industrialist of the nineteenth
century, a pioneer in the development of structural,
prefabricated and reinforced concrete.Coignet was the first to
use iron-reinforced concrete as a technique for constructing
building structures.In 1853 Coignet built the first iron reinforced
concrete structure, a four story house at 72 rue Charles Michels
in the suburbs of Paris.Coignet's descriptions of reinforcing
concrete suggests that he did not do it for means of adding
strength to the concrete but for keeping walls in monolithic
construction from overturning. In 1854, English builder William
B. Wilkinson reinforced the concrete roof and floors in the two-
storey house he was constructing. His positioning of the
reinforcement demonstrated that, unlike his predecessors, he
had knowledge of tensile stresses

4. MATERIALS USED
Cement is the main material used
for RCC. It acts as the matrix in
which other ingredients are
mixed to get the final outcome.
Other than cement, steel
reinforcements comprise the
RCC. It bears all the tensile load
where the compressive load is
taken by the concrete.
REINFORCEMENTS
CEMENT

5. COARSE AGGREGATES
FINE AGGREGATES
The fine aggregates
include silt, sand and
other binding materials. It
holds the concrete and
reinforcements together.
Coarse aggregates are slightly
bigger than the silt and sand
used as binding material.

6. VARIATION IN GRADIANTS

7. Aggregates have two types of moisture:
1. Absorbed moisture – retained in pores
2. Surface moisture – water attached to surface Aggregates have
four moisture states
Oven dry: all moisture removed
Air dry: internal pores partially full & surface dry
Saturated-surface dry: pores full & surface moisture removed
Wet: pores full and surface film
SSD aggregate does not add or subtract water ,not easily obtained
in the field
Moisture Absorption -We must determine how much water dry
aggregate will consume into its voids This takes water away from
the mix and reduces workability & W/C ratio We adjust mix
proportions for absorption We want to provide aggregates water
for absorption & maintain workability of the mix .

8. RCC SPECIFICATIONS
• Shuttering shall be done using seasoned wooden boards of
thickness not less than 30mm.
• Surface contact with concrete shall be free from adhering grout,
nails, splits and other defects.
• All the joints are perfectly closed and lined up.
• The shuttering and framing is sufficiently braced.
• Nowadays timber shuttering is replaced by steel plates.
• All the props of approved sizes are supported on double wedges
and when taken out, these wedges are eased and not knocked out.
• All the framework is removed after 21 days of curing without any
shocks or vibrations.

9. • All reinforcement bars conform IS specifications and are free from
rust, grease oil etc.
• The steel grills are perfectly as per detailed specifications.
• The covers to concrete are perfectly maintained as per code.
• Bars of diameter beyond 25mm diameter are bent when red hot.
• The materials proportion should be as per the specifications of the
concrete.

10. NUMBER OF CEMENT BAGS REQUIRED FOR A
SPECIFIC CEMENT CONCRETE RATIOS
• For cement concrete of ratio 1:1:2(1 cement:1sand/coarse
sand:2graded stone aggregate) require 11no bags of 50kg.
• For cement concrete of ratio 1:1.5:3 require 7.8no bags of 50kg.
• For cement concrete of ratio 1:2:4 require 6 no bags of 50kg.
• For cement concrete of ratio 1:3:6 require 4.25no bags of 50kg.
• For cement concrete of ratio 1:4:8 require 3.2 no bags of 50kg.
• For cement concrete of ratio 1:5:10 require 2.50 no bags of 50kg.
• For cement concrete of ratio 1:6:12 require 2.25 no bags of 50kg

11. METHOD OF PREPARATION
CONCRETE PREPARATION:
In its simplest form, concrete is a mixture of paste and
aggregates, or rocks. The paste, composed of portland cement
and water, coats the surface of the fine (small) and coarse
(larger) aggregates. Through a chemical reaction called
hydration, the paste hardens and gains strength to form the
rock-like mass known as concrete.
Within this process lies the key to a remarkable trait of concrete:
it's plastic and malleable when newly mixed, strong and durable
when hardened.

12. PROPORTIONING:
• The key to achieving a strong, durable concrete rests in the careful
proportioning and mixing of the ingredients. A mixture that does not
have enough paste to fill all the voids between the aggregates will
be difficult to place and will produce rough surfaces and porous
concrete. A mixture with an excess of cement paste will be easy to
place and will produce a smooth surface; however, the resulting
concrete is not cost-effective and can more easily crack.

13. • The quality of the paste determines the character of the
concrete. The strength of the paste, in turn, depends on the
ratio of water to cement. The water-cement ratio is the
weight of the mixing water divided by the weight of the
cement. High-quality concrete is produced by lowering the
water-cement ratio as much as possible without sacrificing
the workability of fresh concrete, allowing it to be properly
placed, consolidated, and cured.
• A properly designed mixture possesses the desired
workability for the fresh concrete and the required durability
and strength for the hardened concrete. Typically, a mix is
about 10 to 15 percent cement, 60 to 75 percent aggregate
and 15 to 20 percent water. Entrained air in many concrete
mixes may also take up another 5 to 8 percent.

14. OTHER INGREDIENTS:
 WATER: Almost any natural water that is drinkable and has no
pronounced taste or odor may be used as mixing water for
concrete. Excessive impurities in mixing water not only may affect
setting time and concrete strength, but can also cause
efflorescence, staining, corrosion of reinforcement, volume
instability, and reduced durability. Concrete mixture specifications
usually set limits on chlorides, sulfates, alkalis, and solids in mixing
water unless tests can be performed to determine the effect the
impurity has on the final concrete.
• AGGREGATES: Aggregates comprise 60 to 75 percent of the total
volume of concrete. The type and size of aggregate used depends
on the thickness and purpose of the final concrete product.
Relatively thin building sections call for small coarse aggregate,
though aggregates up to six inches in diameter have been used in
large dams. A continuous gradation of particle sizes is desirable for
efficient use of the paste. In addition, aggregates should be clean
and free from any matter that might affect the quality of the
concrete.

15. ADVANTAGES
• Reinforced concrete has a high compressive strength compared to
other building materials.
• Due to the provided reinforcement, reinforced concrete can also
withstand a good amount tensile stress.
• Fire and weather resistance of reinforced concrete is fair.
• The reinforced concrete building system is more durable than any
other building system.
• Reinforced concrete, as a fluid material in the beginning, can be
economically molded into a nearly limitless range of shapes.

16. • The maintenance cost of reinforced concrete is very low.
• In structure like footings, dams, piers etc. reinforced concrete is the
most economical construction material.
• It acts like a rigid member with minimum deflection.
• As reinforced concrete can be molded to any shape required, it is
widely used in precast structural components. It yields rigid
members with minimum apparent deflection.
• Compared to the use of steel in structure, reinforced concrete
requires less skilled labor for the erection of structure.

17. DISADVANTAGES
• The tensile strength of reinforced concrete is about one-tenth of its
compressive strength.
• The main steps of using reinforced concrete are mixing, casting, and
curing. All of this affect the final strength.
• The cost of the forms used for casting RC is relatively higher.
• For multi-storied building the RCC column section for is larger than
steel section as the compressive strength is lower in the case of
RCC.
• Shrinkage causes crack development and strength loss

18. PRECAST
• Precast concrete is a
construction product produced
by casting concrete in a reusable
mold or "form" which is then
cured in a controlled
environment, transported to the
construction site and lifted into
place. In contrast, standard
concrete is poured into site-
specific forms and cured on site.
Precast stone is distinguished
from precast concrete by using a
fine aggregate in the mixture, so
the final product approaches the
appearance of naturally
occurring rock or stone.
PRECASTED CONCRETE STRUCTURE

19. • By producing precast concrete in a controlled environment
(typically referred to as a precast plant), the precast concrete is
afforded the opportunity to properly cure and be closely monitored
by plant employees. Utilizing a precast concrete system offers many
potential advantages over site casting of concrete. The production
process for precast concrete is performed on ground level, which
helps with safety throughout a project. There is a greater control of
the quality of materials and workmanship in a precast plant rather
than on a construction site. Financially, the forms used in a precast
plant may be reused hundreds to thousands of times before they
have to be replaced, which allow cost of formwork per unit to be
lower than for site-cast production.

20. EXAMPLES OF RCC PRECAST