PCC Concrete | types of PCC concrete mixing | PCC concrete making procedure

 What is P.C.C concrete?

Plain Cement Concrete is the abbreviation for plain cement concrete. PCC is an unreinforced mixture of cement, fine aggregate (sand), and coarse aggregate. To avoid direct contact of reinforcement of concrete with soil and water, PCC Concrete is spread on the soil surface before concreting the whole structure.

Throughout history, concrete has been utilised for a variety of purposes, including architecture, infrastructure, and more. Despite the fact that concrete is being utilised in construction today. On any building site, the phrases RCC (Reinforced Cement Concrete) and PCC Concrete (Plain Cement Concrete) are used interchangeably.

RCC stands for Reinforced Cement Concrete, in which steel bars are used to provide tensile strength, whereas no steel bars are used in PCC.

Before beginning any RCC masonry work directly on the excavated soil, PCC concrete is used to create a flat surface, and it is avoided keeping the concrete perpendicular to the soil so that the mixture is combined with the soil and the water is collected by the PCC. It can also be weakened in order to prevent soil from forming.

Only "cement concrete (CC)" or "binding concrete" can be used to describe plain cement concrete. It's also known as "Mud Mat" by others.

P.C.C pouring

PCC Ingredients in Construction

The basic components of plain cement concrete are as follows:

1.       Coarse Aggregates

are a type of coarse aggregate. Hard dust, grime, and other foreign components of granite or comparable stone should not be present in the coarse aggregates used in PCC. The stone ballast will be no more than 20 mm in diameter. All coarse material should be kept in a 5 mm square mesh and graded to ensure that voids do not exceed 42%.

2.       Aggregates of Fine Size

The fine set is made up of coarse sand with hard, sharp, and angular grains that must pass through a 5 mm square mesh screen. The sand must meet certain requirements, including being clean and devoid of dust, dirt, and organic materials. There will be no utilisation of sea sand.

3.       Portland cement

Pozzolana Cement (PPC) is a type of cement that is often used in plain cement concrete. It should meet the standards in terms of tensile and compressive stresses, as well as fineness.

4.       Water

The water utilised will be clean and relatively free of potentially dangerous components such as oil, acids, alkalis, salts, and plant growth. In general, potable water with a pH of at least 6 should be utilised. IS 456:2000 Clause 5.4, Page No 15 specifies the maximum allowable limits for solids.

PCC Concrete Production

The following is a step-by-step guide on manufacturing plain cement concrete (PCC)

1.       Ingredients are chosen

2.       Ingredients are combined.

3.       Transport and placement

4.       Concrete compacting

5.       Concrete finishing and curing

PCC Ratio

The PCC concrete mix ratio is 1:5:10 (one component cement, five parts sand, and ten parts aggregate). PCC is used in construction to create a flatbed for footings.

Concrete Mixing Techniques

Concrete production is the process of combining various elements — water, aggregate, cement, and any other additives – to make concrete. Concrete manufacture is a time-consuming process.

Workers must place the concrete before it hardens after it has been mixed. In modern times, most concrete is produced in a big industrial facility known as a concrete plant, or more commonly a batch plant.

When it comes to concrete mixing, the three procedures listed below are employed to produce effective and high-quality concrete.

1.       Concrete mixing by hand (Mixing concrete manually without a mixer machine)

2.       Concrete mixing by machine (Mixing concrete with a mixer machine)

3.       Ready-to-Use Concrete (Mixing in automatic or semi-automatic batching plant)

Different types of concrete admixture are required for different types of constructions. It is vital to utilise the proper way of mixing concrete for the specific usage and application in order to get effective results.

The manner of concrete mixing is influenced by a number of elements, including Location of the construction site with enough land for construction activity, such as densely populated urban areas.

Ample room for concrete batching and mixing, as well as aggregate storage Quantity of concrete required the volume of concrete required per hour or per day, for example, is part of the building timetable.

The height at which the concrete will be poured Cost Let's take a closer look at each of the three concrete mixing procedures listed above.

1. Concrete mixing by hand

Hand mixing is the process of manually mixing concrete ingredients without the use of a mixer equipment. Concrete is only mixed without a mixer for small jobs where the amount of concrete required is low and quality control is not critical. The consistency of the mixture is difficult to accomplish when mixing concrete by hand, and it necessitates extra caution and work.

Concrete Mixing by Hand is a process that involves mixing concrete by hand.

1.       Concrete is mixed by hand on a firm, clean, and non-porous masonry or flat iron sheet plate basis.

2.       A specified amount of sand is put around the platform, followed by the pouring of cement over the sand.

3.       3. In the dry stage, the sand and cement are mixed thoroughly with shovels multiple times until the mixture is fully coloured and free of ridges.

4.       Concrete Hand Mixing - Plain Cement Concrete Concrete Hand Mixing

5.       The measured volume of coarse aggregates is then put evenly over the aforementioned mixture in the same layer and thoroughly stirred.

6.       When batching aggregates, remember to utilise measuring boxes to calculate how much aggregates will be needed. Never utilise or allow the use of 'gameless' for batching, that is, overall quality measurement.

7.       Finally, the entire mixture is well combined, including turning from centre to edge, then back to centre, and so on multiple times. The composite materials then experience depression in the core. Also, with the help of shovels, 75% of the required amount of water is poured to the sediment and blended.

Precautions

·         The base platform should be dry, clean, and free of debris.

·         Mixing should be done with a nice, clean shovel.

·         If the aggregate contains any dirt or trash, it should be washed before usage.

·         When mixing and handling concrete, labourers and masons should wear personal protective equipment such as hand gloves, masks, and other such items.

·         At the end of the day's work, the mixing platform should be cleaned.

2. Concrete mixing by machine

The process of combining the components of concrete with a concrete mixer machine is known as machine mixing. It is extremely effective at meeting the needs of quick mixing times, maximum stability, and uniform concrete quality.

Concrete Mixing Machine Process

1.       To begin, moisten the interior surfaces of the concrete mixer's drum.

2.       The coarse aggregates are added first, followed by sand, and then cement.

3.       In a dry mixing machine, combine the components. It should take between 1.5 and 3 minutes in most cases.

4.       While the machine is running, slowly pour the appropriate amount of water after the dry material has been thoroughly mixed. Don't add any more water than is absolutely necessary. This isn't a good idea because it depletes strength.

5.       After adding water, the concrete must be mixed in the drum for at least two minutes. Remix the concrete if there is any separation after it is unloaded from the mixer.

Precautions

·         Concrete Mixing Machine Safety Precautions

·         Before using the concrete mixer, it must be wet.

·         Keep in mind the mixer drum's time, speed, and number of revolutions as advised by the mixer machine's maker.

·         Concrete must be utilised within 30 minutes of the concrete mixer mixing and discharging it.

·         If your mix is batch, the inner surface of the mixer drum should be properly cleaned after each batch of concrete is discharged. If not, the prior batch's mixing can result in a lump of hardened concrete becoming a part of the next batch, lowering the quality of the concrete.

·         If you're working with a continuous mixture, you'll need to clean the concrete mixer at regular intervals.

·         At regular intervals, the interior of the concrete mixer should be thoroughly inspected for damage, breakage, or corrosion.

3. Ready-mix concrete

In India, people and rudimentary mixer machine equipment are often utilised to produce traditional concrete on-site. Ready-mix concrete, on the other hand, is increasing favour these days.

Finished mixing is especially beneficial in congested concrete locations or in road construction when there is little or no space for mixing units or material storage. Because the concrete is mixed and blended in a computerised central batching plant, quality control is simple in this process.

This kind of mixing is ideal for a variety of situations, including congested areas, nighttime concreting, major construction sites, and so on.

In comparison to other mixing procedures, the water/cement ratio in ready-mix concrete may be easily regulated. It is possible to mix the combination, i.e., fly ash and cement are mixed in the exact amount or proportion; otherwise, construction chemicals may be employed excessively. The usage of ready-mix concrete can also alleviate these issues.

P.C.C construction procedure

1.       A truck or truck attachment can deliver the PCC straight to the desired position, or it can be put into a placement equipment for more exact and even placement. After unloading from the transport truck, the PCC that has been heavily moved will separate (become less homogeneous).

2.       Place sand and metal volumetric on the mixing tray in a predetermined proportional quantity. For better and more consistent mixing, dump the required deposits for half a bag.

3.       Half of the bags should be mixed at once, with a depot proportionate to the aggregates.

4.       Using a spade, thoroughly mix the dry depot. Verify that the cement, sand, and metal are evenly distributed.

5.       Pour the necessary amount of water into the aforementioned mixture to keep the water–cement ratio at a working level.

6.       Pour concrete in place using pots (mortar pans).

7.       Claws can be used to spread and level concrete.

8.       If the depth of the pit is great, a labourer should get concrete and place it in the pit to avoid isolation.

9.       Chut can also be used to place concrete in areas with a lot of digging depth.

10.   Depending on the depth of the P.C.C., the concrete can be squeezed with either a steel rammer or a vibrator.

11.   The edges of the shuttering should be tempered and finished with slant, then thapi should be used to give it a smooth and consistent finish.

 

Thank you