Plum concrete: Uses, Preparation, Specifications and Application
What do you mean by Plum Concrete?
Often called cyclopean concrete, plum concrete is a mixture of wet concrete and large, strong, clean boulders or aggregates of roughly 300 millimetres. The plum makes up about 30–40% of the overall weight of the poured-in-place material.
Plum concrete is created by adding medium to large stones as fillers that range in size from 300mm and higher. Enhancing the apparent yield of concrete for a given amount of cement, it prevents the use of too much cement without sacrificing strength.
The inclusion of plum in concrete reduces the amount of hydration heat necessary since it prevents the need for too much cement while preserving the material's strength. Common uses for plum concrete include the construction of gravity dams, embankments, the filling of deep or uneven terrain, foundations, etc. It is a less expensive alternative to normal cement.
What is the difference between Plum Concrete and Plain Cement Concrete (PCC)?
One of the simplest forms of concrete is plain cement concrete, which is composed of cement and water. In order to produce it, essential ingredients such as cement, fine aggregates, and coarse aggregates are mixed together in a mixer.
Plum concrete, on the other hand, is the type of concrete in which large stones are used as filler material instead of aggregates in order to create the desired shape.
Hence, plain cement concrete and plum concrete differ only in that large boulders are added to the concrete mix. In addition to serving as a filler material, it reduces the need for small-sized aggregates, which are usually expensive. In this way, concrete costs can be reduced.
What are the properties of Plum Concrete?
1. The diameter of natural stone or boulders, or plums, typically ranges from roughly 150 mm to 300 mm. After giving the project, the accessibility of pertinent resources, and the findings of pertinent engineering judgements full consideration, the size is decided.
2. Concrete made from plums is best made with sharp-edged stones.
3. Grease, grime, and anything else that could prevent the plum from adhering to concrete should be removed from the plum.
4. It must be of a high standard, durable, and free from segregation, seams, cracks, and any other structural flaws or imperfections.
5. Plum surfaces should not become rounded off from use and ageing.
Manufacturing of Plum Concrete
There are two simple ways to manufacture plum concrete, also known as rubble concrete or cyclopean concrete. In either case, the plums can be added to the concrete mix during mixing or spread over the normal concrete layer and then covered with another layer. When placing the plums in concrete, special attention must be paid to preventing air traps. Following is a general description of the manufacturing process:
1. The quality of the Plum material:
1. The plum must not be flaky and it must not have any kind of clay or dirt.
2. If there is any kind of dust found on the surface of the plum materials then it must be immediately cleaned before usage.
3. For plum materials, it is important that they are tough, durable, and preferably of the same rock as that from which aggregates are made.
2. The batching of plum material:
1. In order to manufacture plum concrete, the stones required for the manufacturing process are carefully selected by hand. A batching process is then carried out on the plum material. You should be able to find plum material up to 300mm in diameter.
2. There should be a maximum of 1/3 of the total volume of concrete devoted to plum material. Workers can either pick the plum material by hand or just pick it randomly from the site.
3. The placing of the Plum Concrete:
1. The amount of concrete needed will decrease by up to 50% and the amount of plum will increase by up to 50% if the plum materials are positioned closely together.
2. A layer of concrete is then poured over the plum material. Another layer of plum material is put over the concrete once the gaps between the plum materials have been gradually filled with concrete.
3. Until the required level is attained, this process is repeated. Air traps must be avoided with great care when putting on plum concrete as they could reduce the strength of the material. One must also make sure that they are distributed randomly.
4. Finishing and curing of the Plum Concrete:
1. A layer of concrete is then poured over the plum material. Another layer of plum material is put over the concrete once the gaps between the plum materials have been gradually filled with concrete. Until the required level is attained, this process is repeated.
2. Air traps must be avoided with great care when putting on plum concrete as they could reduce the strength of the material. One must also make sure that they are distributed randomly.
What are the applications of Plum Concrete?
1. Plum concrete enables the basis's cost to be reduced. When the foundation is on sloping land, plum concrete is utilised to prevent the building from sinking.
2. The concrete smooths the earth beneath the foundation when it is uneven. Furthermore, uneven surfaces on hilly or sloping terrain can be flattened by using it.
To learn more, watch the following video tutorial.
Video Source: DND Construction
3. Plump concrete is highly sought-after when constructing massive structures like dams and bridges that rely on gravity for support. The maximum permitted thickness for plum material used to construct dams and bridges is only 150 millimetres.
4. Leveling the bed surfaces of the water channels is done using plum concrete. Water distribution networks necessitate sturdy construction due to their common underground position. Hence, plum concrete is most suited for use in these structures.
5. There are many situations in which a large mass is needed for the foundation and machine to be stable.
6. This method is used when the only justification for bulk concreting, as with a machine foundation, is to add weight to a foundation.