Friday, February 7, 2020

Session 6 : PCC Work (Plain Cement Concrete) (Free Online Quantity Survey and Estimation Course)

Plain Cement Concrete


1 Name of Work & Description

PCC (Plain Cement Concrete) : This is a sub-base structure of any foundation to ease the foundation work like Shuttering, Reinforcement, concreting, etc. PCC work is required to maintain the bottom level of a foundation in a level. Below PCC we need to do excavation, cleaning, rubble soling, compaction, plum concrete, etc. PCC can prevent termites as well as riotous insects, etc. below PCC we need to do anti-termite treatment, to prevent all insects like Mouse, ant, frog, etc.
PCC is not a reinforced structure; this is just a part of sub-base structure to work easily before foundation.

Types of Plain Cement Concrete
1 Cast in situ PCC
2 Ready mix PCC
3 Hand Mix PCC
4 Screeding
5 slab Cushioning
6 Lime Concrete
7 Topping on Slab
8 Plum Concrete

2 IS Code No.

Plain and Reinforced Cement Concrete IS Code: IS456:2000
Code of Practice for laying in-situ Cement Concrete Flooring: IS2571:1970
Methods of tests for aggregate for concrete: IS: 2386
Compressive strength test for cement mortar cubes: IS: 2250
Methods of sampling and analysis of concrete: IS: 1199
Specifications for fine & coarse aggregate from natural sources for concrete: IS: 383

3 The Drawing Needs to Read.

As we discussed earlier PCC is a base structure which not taking the load, so no separate drawing will be provided by any agency, in all drawing, there is only mentioned thickness, offset of PCC and grade of concrete.
But sometimes in schedule drawing there are details motioned as well as sizes and thickness are also given in the schedule. (As per Picture).
Following the drawing needs to study before start PCC Work.
1 Footing Sectional Drawing
2 Plinth Sectional Drawing
3 Layout of Foundation
4 Footing layout and Schedule.
5 Level Drawing.

 4 Location of Work

Plain Cement concrete is the mandatory base before starting any foundation, the following are some locations where we are found PCC Work.
1 PCC below footing
2 PCC below plinth beam
3 PCC below Raft
4 Floor PCC
5 PCC Below Tremix
6 Screeding on Slab
7 Plum Concrete was more level difference in-ground.

5 Standard Procedure of Work (Step by Step)

Following procedures need to follow before start PCC Work.
1 Checking of Excavation Level and Foundation depth, depth of PCC, plinth Level, etc.
2 Checking of Hard Strata after Excavation.
3 Removal of all loose material.
4 Cleaning of the excavated area before start PCC.
5 Marking of Corner Point with fixing of a rod, and marking of top-level of PCC on it.
6 Fixing of shuttering ply side as per the size given in drawing, or keep offset to the foundation at least 150mm to smooth working space.
7 Keep The top-level of PCC is uniform. If the excavated ground is not is level then do plum concrete after discussing it with the RCC consultant. But keep PCC in level.
8 Fill Concrete as per the given design mix. Which can be generally given in drawing is M10 & M15.
9 Keep the thickness of the PCC uniform which is nearing 150mm or 100 mm as per given in drawing.
10 The next day remove shuttering and regular curing to be done.
11 Now PCC is Ready to Marking of Footing/Foundation and works further according to drawing.

6 Checkpoints

PCC Checkpoints are as follows
1 Excavation level
2 Plinth Top-level
3 Depth of Foundation
4 Cleaning of Loose Material
5 Marking of Outer size of PCC
6 Shuttering of PCC
7 Thickness of PCC
8 Grade of Concrete
9 Quality of Concrete
10 Curing

7 Equipment and Machinery

Cast in situ PCC required following Material
1 0.5 Bag/1 Bag Manual or semi-automatic Concrete Mixer.
2 Weight batcher
3  Wheel Borrow
4 Shovel & Ghamela
5 Thapi,
6  Line Dori
7 Measurement Tape
7 Auto level and staff.

8 Measurements and Quantity Survey

Plain Cement Concrete is measuring in 2 units as Square Meter and Cubic Meter.
Following are the procedures to take and write the measurements of PCC.
If Size of Footing is 1500mm X1500mm and thickness is given 150mm,
Then we can calculate two types of measurements.
1 Square Meter:
Size of Footing: 1500mm X1500mm
One side length of PCC: (1500mm +150mm (Offset) + 150mm (Offset)): 1800mm
Size of PCC: 1800mm X 1800mm: i.e.:1.800mX1.800m
Area of PCC: 3.240 Square Meters

2 Cubic Meters:
Size of Footing: 1500mm X1500mm
Size of PCC (Including Offset):1800 mm X 1800mm: 1.800mX1.800m
Thickness of PCC: 150mm
Concrete Quantity of Footing PCC: 1.800mX1.800mX0.150: 0.486 Cubic Meters

 9 Checklists

Checklist for Plain Cement Concrete is called Pour Card.
1 Excavation Level, Plinth Top Level, Thickness of PCC is Checked.
2 All Loose Material Removed and Cleaned the PCC base surface.
3 Marking is Done including offset to foundation
4 Formwork is cleaned and oiled
5 Formwork free from holes and gaps.
6 Formwork size is as per drawing.
7 Formwork is inline-level and plumb.

Footing PCC

10 Quality Tests

Compression test of Cube
Testing of Cement
Testing of Aggregate

11 On-site Experiences

Importance of Plain Cement Concrete: We executed a industrial renowned beverages company project, before that we are assuming PCC is not as much important structure, but after working on this site we understood the importance of PCC, because there is some cold room made, and we did all the PUF panel (polyurethane foam) work below concrete, now if you got to visit this site you can see this normal, but below Tremix we did a lot of work and PCC and trimix are cushioning to those hidden things.
Mr. Shankar

CBEC India