What Is PCC Concrete?
The term PCC refers to Plain Cement Concrete. PCC is a mixture of cement, fine aggregate(sand), and coarse aggregate without reinforcement. PCC Concrete is spread on the soil surface before concreting maid structure to avoid direct contact of reinforcement of concrete with soil and water.
Concrete has been used for many wonderful things throughout history, either for architecture or infrastructure work, and more. Although concrete is used as construction material nowadays. There are two terms used on any construction site RCC (Reinforced Cement concrete) and PCC Concrete (Plain Cement Concrete) work.
RCC means Reinforced Cement Concrete in which reinforcement means steel bars are used to give it tensile strength and whereas in PCC, no steel bars are used it.
Before starting any RCC masonry work directly on the excavated soil, the PCC concrete is made to form a flat surface and it is avoided to keep the concrete perpendicular to the soil so that the mixture is mixed with the soil and the water removed by the PCC It can also be weakened to prevent soil.
Plain cement concrete can only be called “cement concrete (CC)” or “binding concrete”. Some people also call it “Mud Mat”.
pCC full form in engineering
In engineering, PCC stands for Plain Cement Concrete, which is a basic form of concrete made by mixing cement, water, and aggregates such as sand and gravel. PCC is used in a wide range of construction applications, such as foundations, floors, and pavements.
Read More: What is RCC – Reinforced Cement Concrete
PCC Ratio
PCC ratio stands for Portland cement concrete ratio, which refers to the ratio of Portland cement to the other materials in the concrete mix, such as sand and aggregate. This ratio is crucial in determining the strength and durability of the concrete. A higher PCC ratio results in stronger and more durable concrete, but it also increases the cost.
PCC concrete mix ratio is 1:5:10, which means 1 part of cement, 5 parts of sand, and 10 parts of aggregate. PCC in construction is used to make a level bed for footing.
Importance of PPC concrete
PPC (Portland Pozzolana Cement) concrete is becoming increasingly popular due to its numerous benefits over conventional concrete.
One of the main advantages of PPC concrete is its enhanced strength, which makes it ideal for use in high-rise buildings and structures that require high compressive strength.
Additionally, PPC concrete has a lower carbon footprint compared to traditional concrete, as it uses fly ash as a substitute for some of the Portland cement. This not only reduces the amount of waste generated but also conserves natural resources.
PPC concrete is also more durable and resistant to chemicals, making it an ideal choice for infrastructure projects in harsh environments.
Ingredients of PCC In Construction
The following are the main ingredients of plain cement concrete,
1. Coarse Aggregates
The coarse aggregates used in PCC should be free of hard dust, dirt, and other foreign materials of granite or similar stone. The stone ballast will be 20 mm in size and smaller. All coarse material should be maintained in a 5 mm square mesh and well-graded so that voids do not exceed 42%.
2. Fine Aggregates
The fine set shall consist of coarse sand, consisting of hard, sharp, and angular grains, and shall pass through a 5 mm square mesh screen. The sand shall be of standard specifications, clean, and free from dust, dirt, and organic matter. Sea sand will not be used.
3. Cement
Portland Pozzolana Cement (PPC) is commonly used for plain cement concrete. It should conform to the specifications and have the required tensile and compressive stresses and fineness.
4. Water
The water used will be clean and reasonably free from harmful amounts of harmful materials such as oil, acids, alkalis, salts, and vegetable growth. Generally, potable water shall be used having a pH value of not less than 6. The maximum permissible limits for solids shall be as per IS 456:2000 Clause 5.4, Page No 15.
Making of PCC Concrete
Following is the process of making plain cement concrete (PCC)
- Selection of Ingredients
- Mixing of Ingredients
- Transportation and Placing
- Compaction of concrete
- Finishing and Curing of concrete
Methods for Mixing of Concrete
Concrete production is the process of mixing different ingredients together – water, aggregate, cement, and any additives to produce concrete. Concrete production is time-sensitive.
Once the material is mixed, workers must place the concrete before it hardens. In modern usage, most concrete production occurs in a large type of industrial facility called a concrete plant, or often a batch plant.
When it comes to mixing concrete, the following three mixing methods are used for the production of effective and good-quality concrete.
- Hand Mixing of Concrete (Mixing concrete manually without a mixer machine)
- Machine Mixing of Concrete (Mixing concrete with a mixer machine)
- Ready Mix Concrete (Mixing in automatic or semi-automatic batching plant)
Different constructions require different types of concrete admixture. For efficient results, it is necessary to use the appropriate method of mixing concrete for specific use and application.
Several factors influence the method of concrete mixings, such as
- Location of the construction site with sufficient land for construction activities e.g. highly congested urban areas
- Available space for concrete batching and mixing and storage of aggregates
- The volume of concrete needed
- The construction schedule like the volume of concrete required per hour or per day
- Height at which concrete is to be placed
- Cost
Let’s take a detailed look into each of the above-mentioned three methods of concrete mixing.
Read More: Concrete – Its Materials, Properties, Tests & Cost
1. Hand Mixing of Concrete
Hand mixing is the process of manually mixing the ingredients of concrete without a machine mixer. Mixing of concrete without a mixer is used only for small works where the need for concrete is less and quality control is less important.
In hand mixing of concrete, the uniformity of the mixture is difficult to achieve and requires special care and effort.
Process of Hand Mixing of Concrete
1. Hand mixing of concrete is done on a rigid, clean, and non-porous base made of masonry or flat iron sheet plates.
2. The measured amount of sand is spread over the platform and then the cement is spilled over the sand.
3. In the dry state the sand and cement are mixed well several times with the help of shovels until the mixture is mixed in full color and free from ridges.
4. Subsequently, the measured volume of coarse aggregates is spread over the above mixture in the same layer and mixed properly.
5. Remember to use measurement boxes for batching of aggregates, that is, to determine how many aggregates are to be used. Never allow the use or use of ‘gameless’ for batching, that is, the measurement of total quality.
6. Later, the entire mixture is mixed properly such as turning from center to edge, then towards the center, and again several times. After that, depression occurs at the center of the composite materials. And, 75% of the required amount of water is added to the sediment and mixed with the help of shovels.
7. Finally, the remaining amount of water is added and the mixing process continues until uniform color and consistency of concrete are achieved. The total time taken for the mixing of concrete should not exceed 3 minutes.
Precautions to be taken while shaking concrete
- The base platform should be clean, dirt-free, and water-free.
- Use a good and clean shovel for the mixing process.
- If there is any dirt or debris in the aggregate, wash them before use.
- Personal protective equipment such as hand gloves, masks, etc. should be worn by laborers and masons when mixing and handling concrete.
- The mixing platform should be cleaned at the end of the day’s work.
2. Machine Mixing of Concrete
Machine mixing is the process of mixing the components of concrete with a concrete mixer machine. It is highly effective for meeting the demands of short mixing time, optimum stability, and homogeneous quality of concrete.
Concrete Mixing Machine Process
First, wet the internal surfaces of the drum of the concrete mixer. Coarse aggregates are first placed in the mixer, followed by sand and then cement. Mix the ingredients in a dry state in the mixing machine. Generally, it should be 1.5 to 3 minutes.
After proper mixing of the dry material, slowly pour the right amount of water while the machine is in motion. Do not add more water than necessary. This is not appropriate as it reduces strength.
After adding water, you must mix the concrete in the drum for a minimum of two minutes. If there is any separation of concrete after unloading from the mixer, remix the concrete.
Precautions of Concrete Mixing Machine
The concrete mixer must be wet before using the machine. Keep in mind the time, speed, and number of revolutions of the mixer drum as recommended by the manufacturers of the mixer machine. Concrete must be used within 30 minutes after mixing and discharging by the concrete mixer.
If your mixture is batch-type, after discharging a batch of concrete, the inner surface of the mixer drum should be thoroughly cleaned. If not, mixing the previous batch can form a lump of hardened concrete to form a part of the subsequent batch and deteriorate the quality of the concrete.
If your mixture is of a continuous type, it is necessary to clean the concrete mixer after a fixed interval.
The interior of the concrete mixer should be carefully inspected at regular intervals to check for damage, breakage , or corrosion.
3. Ready Mix Concrete
In India, on-site production of traditional concrete with the use of manpower and primitive mixer machine equipment is commonly used. However, ready-mix concrete is also gaining popularity nowadays.
Finished mixing is particularly useful in concrete-congested areas or in road construction, where little or no space is available for mixing plants or for storage of aggregates. In this method, the quality control of the concrete is easy as the concrete is mixed and blended in a mechanized central batching plant.
This method of mixing is very useful for many places i.e., in a congested area, at night in concreting work, large construction sites, etc.
In ready-mix concrete, the water/cement ratio can be easily controlled compared to other mixing methods. It is possible to mix the mixture, ie, fly ash and cement are mixed in the exact quantity or proportion otherwise construction chemicals may be overused. These difficulties can also be avoided by the use of ready-mix concrete.
Placing of Plain Cement Concrete
The PCC can be placed directly to the desired location by a truck or truck attachment or fed into a placement machine for more precise and even placement. The PCC that is once highly transported after unloading from the transport truck will separate (become less homogeneous).
Read More: Concrete Cube Fails in Test After 28 days
Work Procedure of PCC Construction
- PCC can be placed directly to the desired location by a truck or truck attachment or fed into a placement machine for more precise and even placement. The PCC that is once highly transported after unloading from the transport truck will separate (become less homogeneous).
- Taking a specified proportional quantity, deposit sand and metal volumetric on the mixing tray. It is advisable to dump the required deposits for half a bag for better and uniform mixing.
- Mix half the bags at a time, with a depot proportional to the aggregates.
- Mix the dry depot thoroughly using a spade. Confirm that cement, sand, and metal are mixed equally.
- Pour the required amount of water into the above mixture, to maintain the water-cement ratio and to obtain workable concrete.
- Using pots (mortar pans), pour concrete into place.
- Use claws for spreading and leveling concrete.
- If the depth of the pit is high, labor should obtain concrete in the pit and put concrete in a position to avoid isolation.
- Chut can also be used for placing concrete where the digging depth is high.
- The concrete that is poured can be compressed either by a steel rammer or by a vibrator, depending on the depth of the P.C.C.
- The edges of the shuttering should be tempered and finished with a slant followed by a smooth and uniform finish with thapi.
Uses of PCC Concrete
Plain cement concrete is commonly used for foundations. However, it has other uses:
- As concrete on the bed flooring, under the column footings, and on the walls below the beam.
- As a solid to get a hard and uniform surface on the surface of the window and ventilator.
- To counter concrete on parapets and composite walls.
- To flag the area around the buildings.
- Pavement Making.
- For making tennis courts, basketball courts, etc.
- Plinth protection
- Storm/sewer on drains, small retaining walls.
PCC Concrete Grades
Regular grades of concrete are M15, M20, M25, etc. For PCC concrete works, generally, M15 is used. For reinforced concrete construction minimum M20 grade of concrete is used.
The concrete admixture ratio is the ratio of its components such as cement, sand, aggregate, and water. These mix ratios are defined based on the type of construction and the power required.
Although IS code gives nominal and standard PCC concrete mix ratios for various construction tasks based on experience and testing.
Concrete Mixing Type
- Nominal concrete admixture
- Ready mix concrete mixture
- Nominal mixture
1. Nominal Concrete Admixture
Nominal concrete mixtures can be used for concrete grades M5, M10, M15, and M20. The ratio of its components is given below:
The penalty ratio for coarse aggregates should be adjusted from the upper limit to the progressively lower limit, as the grading of the fine aggregate becomes finer and the maximum size of the coarse aggregate becomes larger. Graded coarse aggregate should be used.
2. Ready Mix Concrete Mixture
In designed concrete mixtures, the ratio of the ingredients of the concrete is determined to achieve concrete of specified properties with the overall economy. Concrete is classified according to its compressive strength given in the table below: –
Read More: What is Batching of Concrete? & Types of Batching of Concrete Methods
Different Grades of Concrete
1. Normal Grade Concrete
Concrete Grade | Mix Ratio | Compressive Strength | |
MPa (N/mm2) | psi | ||
Normal Grade of Concrete | |||
M 5 | 1: 5: 10 | 5 MPa | 725 psi |
M 7.5 | 1: 4: 8 | 7.5 MPa | 1087 psi |
M 10 | 1 : 3 : 6 | 10 MPa | 1450 psi |
M 15 | 1 : 2 : 4 | 15 MPa | 2175 psi |
M 20 | 1 : 1.5 : 3 | 20 MPa | 2900 psi |
Generally, M5, M10, and M15 grades of concrete are used for PCC (plane cement concrete) work like leveling courses, bed footing, etc.
The unit weight of plain cement concrete (PCC) is 2400 kg/m3 or 24 24 KN/m3.
The unit weight of reinforced cement concrete (RCC) is 2500 kg/m3 or 25 KN/m3.
M 20 is used for RCC (reinforced cement concrete) work such as slabs, beams, columns, footings, etc. (for light exposure).
Concrete Grade | Mix Ratio | Compressive Strength | |
MPa (N/mm2) | psi | ||
Normal Grade of Concrete | |||
M 5 | 1: 5: 10 | 5 MPa | 725 psi |
M 7.5 | 1: 4: 8 | 7.5 MPa | 1087 psi |
M 10 | 1 : 3 : 6 | 10 MPa | 1450 psi |
M 15 | 1 : 2 : 4 | 15 MPa | 2175 psi |
M 20 | 1 : 1.5 : 3 | 20 MPa | 2900 psi |
2. Standard Grade Concrete
Concrete Grades M 25, M 30, and M 35 are used for RCC (reinforced cement concrete) such as foundations, footing columns, beams, slabs, etc.
M-40 grade is used for prestressed concrete work, slabs, beams, columns, footings, etc.
M-45 and M-50 grades are used for RCC, runway, concrete road (POQ) prestressed concrete girders, RCC columns, prestressed beams, etc.
M-55 grade is used for prestressed concrete girders and piers etc.
3. High Strength Concrete
Concrete Grade | Mix Ratio | Compressive Strength | |
MPa (N/mm2) | psi | ||
High Strength Concrete Grades | |||
M 50 | Design Mix | 50 MPa | 7250 psi |
M 55 | Design Mix | 55 MPa | 7975 psi |
M 60 | Design Mix | 60 MPa | 8700 psi |
M 65 | Design Mix | 65 MPa | 9425 psi |
M 70 | Design Mix | 70 MPa | 10150 psi |
M-60, M-65, and M-80 are used for RCC work where high compression power is required such as high-rise buildings, long-span bridges, ultra-thin white toppings and dispersal of dams, coastal Construction, etc.
Applications of PPC Concrete
PPC (Portland Pozzolana Cement) concrete has a wide range of applications in the construction industry due to its various advantages. Here are 10 common applications of PPC concrete:
- High-rise buildings and skyscrapers
- Bridges, flyovers, and viaducts
- Dams, canals, and water storage structures
- Marine structures, such as ports and harbors
- Nuclear power plants and other industrial structures
- Roadways, pavements, and airport runways
- Underground structures, such as tunnels and subways
- Pre-cast concrete products, such as pipes and slabs
- Concrete blocks and bricks for masonry work
- Decorative concrete, such as stamped concrete and exposed aggregate concrete.
Do’s and Don’ts of PCC Works
Do’s
- PCC shuttering must be of the exact size and thickness
- Water should be mixed with the bucket, in a measured volume, according to the w / c (water/cement) ratio.
- Use slopes or extra labor to pour concrete where the depth is high.
- Remove any loose material from the sides of the pit, so that no soil or other material falls into the pit during the concrete.
- If the water table is high, then de-watering should be done at the same time during concreting.
Don’ts
- Do not mix the material on bare ground.
- Do not allow PCC without formwork.
- Do not pour concrete without leveling and compacting.
- Do not pour concrete into the pit from a height of more than 1.5 meters.
- Do not allow excess cement mortar on top of the PCC. For smooth finishing.
Advantages of PCC Concrete
- The required coverage for the lower reinforcement is ensured, as the cover blocks rest on a firm PCC.
- The effective depth of the RCC members is achieved because the formwork can be fixed easily, evenly, and firmly, resulting in better dimension accuracy of the foundation RCC member.
- Reinforcement steel bars, mounted on PCC, are never in contact with ground soil, which can be chemically active and cause steel corrosion in the immediate future.
- Ease of steel cages and increased productivity.
- Concrete does not bond with the soil (soil) of the ground; PCC acts as a soil barrier and is bonded to well-overplayed structural grade concrete.
Conclusion:
In conclusion, PCC (Plain Cement Concrete) is a commonly used concrete in construction due to its durability, strength and cost-effectiveness, and it consists of cement, water and aggregate and it providing a solid foundation for various structures.
Proper reinforcement is necessary to minimize cracking and shrinkage issues, overall PCC concrete is a reliable and versatile material which contributes to the stability and longevity of construction projects.
PCC offers good compressive strength so it capable to bear heavy loads, and it also exhibits resistance to weathering, chemical and abrasion.
Also the PCC provide a smooth and level surface and it making it suitable for flooring and base preparation, however proper curing techniques and reinforcement
FAQs:
What is Plain Cement Concrete (PCC)?
Plain Cement Concrete (PCC) is a construction material made by mixing cement, fine aggregates (such as sand), and coarse aggregates (such as gravel or crushed stone) with water. It is commonly used as a base layer for floors, foundations, and other structural elements in buildings and infrastructure.
What are the main components of PCC?
The main components of PCC are cement, fine aggregates (sand), coarse aggregates (gravel or crushed stone), and water. These materials are mixed in specific proportions to create a homogeneous mixture.
What is the purpose of using PCC in construction?
PCC is primarily used as a foundational material to provide a level and stable base for various structures. It distributes loads evenly and helps in preventing soil erosion. PCC also acts as a protective layer for the reinforcement in reinforced concrete structures.
What is the process of laying PCC?
The process of laying PCC involves preparing the sub-base, placing formwork to define the shape and dimensions, mixing the concrete ingredients in the desired proportions, pouring the mixture into the formwork, spreading it evenly, and compacting it using appropriate tools or equipment. The concrete is then left to cure and harden.
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