Plain Cement Concrete - Blinding Concrete 2tn5c

1 Plain Cement Concrete (PCC) is also called as Cement Concrete (CC) or Blinding Concrete. It is used for leveling, bedding for footings, grade slabs, concrete roads etc. PCC is used to provide non-porous, rigid, impervious, firm and leveled bed for laying RCC, where earth is soft and yielding. PCC can be use over brick flat soling or without brick flat soling. PCC also used as filler like lump concrete; this is a mix of PCC and boulder. It consists of cement, sand and coarse aggregates mixed with water in the specified proportions, the following proportions are mostly using:For Foundation – Concrete Mix M10 (1:3:6) ie; 1 part of cement, 3 parts of sand and 6 parts of coarse aggregates). For Car park – Concrete Mix M15 (1:2:4) ie; 1 part of cement, 2 parts of sand and 4 parts of coarse aggregates). i)

Cement – Portland cement is using as a bonding material

ii)

Fine Aggregate – Sand of FM (Fineness Modulus) range 2.3 to 3.1 as per ASTM.

iii)

Coarse aggregate – Size 20mm downgrade.

iv)

Water – Pure drinkable water.

Usually PCC is made in a nominal mix. Aggregate used in PCC is 20mm. Quantity is measured in Cum (m3), ( ie; L x W x Thickness ) Average weight of PCC IS 2400 Kg/m3 PCC is very strong in compression and weak in tensile strength.

2 Steps / Process:1. Clean dust, foreign material or loose earth from the area. 2. Keep formwork for PCC with wooden planks as per specified dimensions. 3. Spread polythene over the bed of PCC. 4. Make level pillars by fresh concrete in the area at suitable intervals but not more than 2m c/c both ways. 5. Mixing can be done by hand mixing or by machine mixing. 6. Place the concrete gently (but don’t through) from one side. 7. Laying and compaction should be done before setting of the concrete ie; within 30 minutes. 8. Use wooden rammer for compaction and finishing of PCC. 9. After 24 hours of laying PCC, cure (moist) the concrete surface by flooding with water or by covering with moist gunny bags at least for 7 days.