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What Is Plum Concrete | Plum Concrete Meaning | Plum Concrete Ratio | Plum Concrete Specification

What Is Plum Concrete

What Is Plum Concrete?

Plum concrete is used in special cases where the soil level is very uneven. The use of this concrete reduces the cost of plum concrete as compared to PCC concrete. Plum concrete is hard rubble and is made of a mix design m10.

Which is usually proportional to 60% rubble and 40% M10 mix design concrete. Plumb concrete is mainly used on uneven surface and large areas. According to IS code, 150mm to 230mm rubble is best in plum concrete.

Plum means large stone. If we say it in technical language, it can be called boulder or coarse aggregates.

This type of concrete is defined as a mixture of four materials, sand, coarse aggregate, cement, and rubble, that are placed below the foundation or footing of a structure to achieve a level surface for equal distribution load.

Plum Concrete Ratio

According to IS code, 150 mm to 230 mm rubble is best in plum concrete. Plum concrete is mainly useful for waterlogging areas and uneven surfaces.

The large stones used are known as plums. These plums are used in the making of mass concrete.

Plum Concrete Rate: volume of plums should not exceed 30%-40% of the total volume of concrete. The plum concrete is also referred to as Rubble concrete or cyclopean concrete. The plum should not be larger than one-third or the cross-section of the concrete mixer.

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Purpose of Plum Cement Concrete

Plum Concrete

Plum concrete is used to attain the required surface level below the foundation of footing.

It is most effectively used to lessen the cost of PCC if the required thickness of PCC is large
plum concrete is most used in mass concreting work such as side slope, barrier, and gravity dams.

Plum concrete has a high vibration resistance which is especially used in roads, side slopes, machine foundations. Plum concrete is economical in mass concrete, gravity dam, bridge, etc.

Where the size of the plum is kept to 150 mm. Bedding in water-channel and plum concrete in its bend part is effective.

Plum concrete in the embankment on the side slope of the highway gives protection to the side. For example, in the construction of a residential building, if the small area under a footing is too steep, then it is preferable to use plum concrete.

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Use of Plum Concrete

Plum Concrete

  1. A Plum concrete wall is specially adopted when the surface is uneven and waterlogging area.
    The main purpose of plum concrete is to achieve the required strength and reduces the cost.
  2. Plum concrete is suitable for highway side slope, open channel side slope, and base purposes.
  3. Used for leveling surfaces, especially in mountainous areas where the stone is also readily available, and costing can also be maintained.

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Plum Concrete Procedure

Plum Concrete

  1. Dressing and leveling should be done where plum concrete is to be applied, and loose soil should be removed from the foundation. It should then be compacted.
  2. Then the side shuttering of the footing should be done.
  3. Adjustment should be done in such a way that 150 mm concrete comes around each stone.
  4. The stone used in plum concrete should be hard, and durable.it should not be flaky.
  5. In plum concrete, the plum should be kept close to each other so that concrete can be used effectively.
  6. Plum concrete should not contain more than 30% of the total amount of concrete.
  7. Plum concrete should be layer-wise so that sufficient strength is obtained.
  8. A special vibrator should be used to prevent a void between the plum during concreting.
  9. Curing should be done for at least 7 days.

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Plum Concrete

  1. Plum concrete is useful where the base is to be made during the rainy season as the base is completely wet and the height of the level increases as the soil is removed.
  2. In plum concrete, the plum should be kept close to each other so that concrete can be used effectively.
  3. Plum concrete is economically best to cover uneven surfaces and large areas.
  4. Plum concrete is suitable for highway side slope, open channel side slope, and base purposes.
  5. Where the size of the plum is kept to 150 mm. Bedding in water-channel and plum concrete in its bend part is effective.
  6. Plum concrete in the embankment on the side slope of the highway gives protection to the side.
  7. Plum concrete has a high vibration resistance which is especially used in roads, side slopes, and machine foundations.

Also Read: What Is Fire Escape Staircase? | Types of Fire Escaping Stairs | Fire Escape Staircase Regulations

Disadvantage of Plum Concrete

Plum Concrete

  1. To make plum concrete, the plum has to be arranged close to the ground surface, which takes time.
  2. Plum concrete has to be arranged layerwise, which makes shuttering longer, which makes shuttering more expensive.
  3. Plum has to be arranged layer-wise in concrete which requires skilled labor.
  4. Plum concrete has to be layer-wise concrete taking care that void does not remain.
  5. For plum concrete, it is necessary to arrange the plum layer-wise in which concrete comes in the void between the plum. If void remains, the strength of concrete decreases.
  6. Being able to do plum concrete layer-wise requires shuttering, which takes time.
  7. Plum concrete has a high weight of plum, which makes it difficult to transport.
  8. Adjusting the rubble for plum concrete takes time and requires skilled labor.
  9. Cost can be nominal only where plum concrete is to be applied over a large area.
  10. Economically expensive for a small area.

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Preparation of Plums in Concrete

Plum Concrete

1. Check the Quality of plum material.

  • The stones to be used for plum concrete should be made of strong, hard, and ideal rock.
  • The stones should not be of flaky type.
  • Stones used for plum concrete should be cleaned before use.

2. Batching

  • First the batch is prepared according to the size of the plum.
  • The size of plum in batching should not be more than 300mm.
  • The plum material will be hand-picked or randomly selected by the workers and taken to the site.

3. Placing Plum Concrete

  • For plum concrete, it is necessary to arrange the plum layer-wise in which concrete comes in the void between the plum.
  • Where the plum is to be used, the plum should be washed first and all dripping surface water removed before inlaying the concrete.
  • The stone shall not be dropped in place, but each stone shall be laid and carefully embedded so as to avoid any injury to the form or adjacent masonry and in such as manner that no plan of the weakness of unnecessary seams occurs in the structure.

Also Read: What Is a Dead Load? | What Is Live Load? | Difference Between Dead Load Vs Live Load

Plum Concrete Specification

  1. When the thickness of PCC is a high and uneven slope, plum concrete should be done.
  2. Plum concrete should not contain more than 30% of the volume of concrete.
  3. The stones used for plum concrete should be hard, durable, and not flaky.
  4. The crushing strength of stones used for plum concrete should be 100 kg/cm2.
  5. The mix of m10 should be proportional to the concrete used for plum concrete, and the maximum size as aggregate should be 25 mm.
  6. The amount of plum used in plum concrete should not exceed 40% of the total volume.
  7. Plum concrete layer is done wisely. The height of each layer should not be more than 300 mm.
  8. Plum concrete should be cured for at least 7 days for which Hesson cloth can be covered and sprinkled with water.
  9. Plum Concrete Density is 2600 kg/m3.

Also Read: What Is Fire Escape Staircase? | Types of Fire Escaping Stairs | Fire Escape Staircase Regulations


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Frequently Asked Questions (FAQ)

Plum Concrete Retaining Wall

Plum concrete is actually an economical variation of mass concrete. The use of plum concrete is preferred if the required thickness of PCC is excessive or large.

What Does Plum Mean in Construction?

In construction or carpentry, the term plumb refers to a line or feature that is perfectly vertical. In technical design, it represents an imaginary line that runs straight to the center of the earth. Plumb is the counterpart to level, which means to be perfectly horizontal.

Plum Concrete Meaning

Plum concrete is also referred to as Cyclopean Concrete or Rubble concrete. It should not be greater than one-third of the concrete mixer cross-section. As per technical specifications, plum concrete should be formed with a mixture of 40% large stones and 60% plain cement concrete.

Purpose of Plum Concrete

Plum concrete is used to attain the required surface level below the foundation and footing. It is used to lessen the cost of PCC if the required thickness of PCC is large. Primarily it is used in mass concreting work such as side slopes, barriers, and gravity dams.

Plum Aggregate

Plum concrete is used at the water channel beds. It is used mostly in mass concrete works like concrete gravity dams or bridge piers In such cases plum aggregate about 150 mm in size are used as coarse aggregates to mix a plum concrete.

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