Plum Concrete

Plum concrete is a mix of wet concrete and a plum. It is also referred as cyclopean concrete as well as rubble concrete.

Plum contributes to around 30-40% of the entire mass of concrete.

It is a cost-effective kind of mass concrete with several varieties of concrete.

Plum concrete is better if the done by adding of PCC is large or enormous.

In this article you’ll learn:

  • Purpose of the Plum concrete.
  • Types of Plum concrete.
  • Merits and Demerits Plum concrete.
  • Lots more.

So, if you’re ready to go with it, this article is for you.

Let’s jump into it!

What is Plum Concrete?

Plum concrete is mostly utilized where mass concreting is necessary, such as when building gravity dams, embankments, filling deep or uneven terrain, foundations, and so on.

This is mostly done beneath the foundations, where the amount of levelling course may be excessive because of the high slope of the strata.

The addition of plums to the concrete decreases the heat of hydration by preventing the need for an excessive amount of cement without sacrificing strength.

Purpose of Plum Concrete:

  • This concrete can be used to provide the required surface level underneath the foundation and footings. If the needed thickness of PCC is substantial, it is utilized to lower the cost of PCC.
  • It is often used in large-scale concrete constructions including side slops, barriers, and gravity dams.
  • It should be utilized if the little area under a footing in the creation of a residential project is too mountainous.            
Plum Concrete

Manufacturing Process of Plum Concrete:

Step 1 – Plum Material Transportation:

The rocks are the massive Stone size that laborers can readily move, not too big or little.

Step 2 – Surface Preparation – Levelling and Cleansing:

The first step is to level and clean the surface, removing any soft dirt that might create limited bearing capacity.

After cleaning and grubbing, water is poured on the area to moisten it before plum concrete is placed.

The goal of the water sprinkling is to ensure that the concrete is thoroughly bound to the ground surface.

While sprinkling water, an anti-termite chemical is poured, which is now required for a structure’s faultless foundation.

Step 3 – Plum Concrete Pacing and Spreading:

Boulders are strewn over the ground with small gaps between them layer by layer, and concrete is poured using a compressor all over the boulders in each layer, slowly permeating into the gaps between the boulders.

After pouring concrete, stones are placed into the concrete again, and the procedure is repeated until the desired level surface is obtained.

Step 4 – Curing of Plum Concrete:

 Curing should be completed during the following 7 days. Jute bags are put over the whole surface of the concrete to keep moisture in place after hardening.

Boulders should be examined before distributing, and if any dirt or clay is discovered, it should be well cleansed.

Specifications for Plum Concrete:

  • Plum must be made of black trap basalt with a crushing strength of at least 100 Kg/sqm.
  • The concrete must have a nominal mix ratio of 1:4:8 and aggregate with a maximum size of 25mm.
  • The plum volume must not exceed 50% of the total volume.
  • The fissures must be at least 150 mm wide.
  • The layer must not be wider than 900mm.
  • Plums larger than 160 mm in diameter and of any acceptable size may be used in plain concrete work up to the value of 20% by volume of concrete when explicitly allowed by the technician.
  • Therefore, in all situations, the plums must be uniformly scattered and no closer than 150 mm from the surface.

Advantages of Plum Concrete:

  1. Plum concrete reduces the expense of thick walls. Concretes are made of Portland cement.
  2. It utilizes in the building of machine foundations where a considerable amount of concrete is necessary for the foundation’s and machine’s safety.
  3. It is used to build the beds of water channels.
  4. Level huge holes or rough terrain at the bottom of foundation digs to save money on development. foundation excavations. In this technique, the foundation’s bottom level or bed is reached utilizing low-cost yet sturdy materials.

Disadvantages of Plum Concrete:

  1. Concrete placing and curing are not as strictly controlled as the production of many other components, like structural steel and laminated wood.
  2. It has a very low tensile strength and needs to be reinforced in the concrete tensile region with reinforcing steel.
  3. Formwork is required for casting and moulding as well as keeping the concrete in place till it cures appropriately.
  4. They cannot be shaped.
  5. Plums with concrete may cause cracking and reduce permeability.
Properties of Plum (Aggregate):
  • The plum that is used to make plum concrete must meet the ASTM standard. Its desirable characteristics are as follows:
  • Natural stone or boulders, such as plum, are generally 150 mm, 200 mm, 300 mm, or bigger in size. The size is determined by the project, material availability, and engineering considerations.
  • It is best made using angular-shaped rocks.
  • It should be free of oil, dirt, and other highly unsafe pollutants that might impede proper adhesion or bonding with concrete.
  • It should be of excellent quality, sound, and long-lasting, with no segregation, seams, fractures, or other structural flaws or problems.
  • Plum should also be devoid of worn or weathered edges and have a spherical surface.
Also read:  Geopolymer Concrete | Prestressed Concrete | Underwater Concrete


Concrete is one of the world’s most adaptable and widely utilized building materials.

Plum concrete is a form of concrete that uses moderate to big stones as filler material instead of particles.

It is mostly employed in mass concrete structures such as concrete gravity dams and bridge piers.

Hello, I'm Rahul Patil founder of, I had studied B.E. Civil. This blog provides authentic information regarding civil structures, equipment, materials, tests & much more.

Leave a Comment