What does C20 concrete indicate?

A concrete of grade C20 indicates that the concrete has a compression resistance of        20 N/m㎡  per square millimeter in 28 days.

Ratio for grade C20.

C20 is 1: 2: 4 (cement,fine aggregate and coarse aggregate).

Where C20 is the symbol of a cylindrical sample, in which cement, fine aggregate, coarse aggregate is added in such a proportion that it has a characteristic compressive strength of 20 N/m㎡ after 28 days of curing.

Figure:- Solid Concrete sample for testing

Normally, the strength of the cylinder sample = 0.8 x the strength of the cube.

Example: - M20 is equal to C25

Differences between:

OPC cement vs PPC cement

Hydraulic lime vs Fatlime

Bolt vs Screw

Concrete vs Mortar

CPM vs PERT

Pier vs Abutment

Culvert vs Bridge

Whole Circle Bearing vs Quadrantal Bearing

Lintel level vs Sill level vs Plinth level

Construction Joint vsExpansion Joint

One way slab vs two wayslab

Site Engineer vs SiteSupervisor

For Testing:

Slump cone test, Silt content, Water absorption, Bulking of sand
Compaction factor test of concrete
Los Angeles Abrasion test on Aggregates