Tuesday, January 31, 2017

Techshore Inspection Services : Plum concrete

Plum concrete
Concrete is a mixture of cementitious material, water, fine and coarse aggregates with or without admixtures. Cementitious material means cement or cement mixed with mineral admixtures like pozzolanic fly ash (PFA),grounded granulated blast furnace slag(CGBFS),micro silica etc.
  • Plum concrete is a special type of concrete which is usually done where the surface is uneven and to minimize the costing of concrete. For e.g. below footings of residential buildings where in a small portion where the slope of ground below single footing is 1:10 to 1:50 in that case to save the cost of concrete plum is usually preffered.This finally leads to minimize the construction cost of building in all.
  • The original idea of the use of aggregate as an inert filter can be extended to the inclusion of large stones up to 300mm size in normal concrete; thus the apparent yield of concrete for a given amount of cement is increased. The ensuing concrete is called plum concrete or other name as Cyclopean concrete.
  • These large stones which used are called plums and it used in a large concrete mass. The volume of plums should not exceed 20-30% of the total volume of the finished concrete and they are to be well dispersed throughout the mass. This is achieved by placing a layer of normal concrete, then spreading the plums, followed by another layer of concrete and so on. Care must be ensuring that no air is trapped underneath the stones.
  • The plums must have no adhering coating. Otherwise, discontinuities between the plum and the concrete may induce cracking and adversely affect permeability.
The following figures (1 & 2) showing the diagram of plum concrete. 




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