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Concrete Grade details like M25, Initial Setting Time, Block making Machine & Road Construction

Concrete Grade, M25, Setting Time, Block Machine & Road Construction

Concrete Grade details of different strength like M25 etc. Also some information on the Concrete initial setting time. Some detailed specification on Concrete Block making Machine. Also, stages of Concrete Road Construction. All of these are explained below to have a wider knowledge of the same.

Concrete Grade details like M25, Initial Setting Time, Block making Machine & Road Construction

Concrete Grade :

Concrete Grade is defined as the minimum strength the concrete achieved in 28 days of initial construction. The grade of concrete is measured in MPa, where M represents mix and the MPa denotes the overall strength. There are different types of concrete grades which are suggested as per the applications. Details are as follows:

Concrete GradeMix Ratio (cement : sand : aggregates)Compression StrengthUse
Basic Concrete Grade
M51 : 5 : 105 MPaPCC
M7.51 : 4 : 87.5 MPaPCC
M101 : 3 : 610 MPaPCC
M151 : 2 : 415 MPaBedding
Medium Concrete Grade
M201 : 1.5 : 320 MPaRCC
Concrete Grade M251 : 1 : 225 MPaRCC
M30As Per Mix30 MPaRCC
M35As Per Mix35 MPaRCC
M40As Per Mix40 MPaCommercial RCC
M45As Per Mix45 MPaCommercial RCC
High Concrete Grade
M50As Per Mix50 MPaCommercial RCC
M55As Per Mix55 MPaCommercial RCC
M60As Per Mix60 MPaCommercial RCC
M65As Per Mix65 MPaCommercial RCC
M70As Per Mix70 MPaCommercial RCC

Concrete Grade M25 :

Concrete Grade M25 is used in construction of Slabs, Beams, Footings, Columns etc. This is one of the most recommended in residential Construction works. It is also used in commercial areas but as per suggested by the Structural Engineer.

  • Type of cement : OPC 53 Grade
  • Maximum nominal size of aggregate : 20mm
  • Minimum cement content : 300 kg/m3
  • Maximum water-cement ratio : 0.50 (Table 5 of IS 456:2000)
  • Workability : 100-120mm slump
  • Exposure condition : Moderate
  • Method of concrete placing : Pumping
  • Type of aggregate : Crushed Angular Aggregates
  • Maximum cement content : 340 kg/m3
  • Chemical admixture type : Super Plasticizer

These are the Specifications for Concrete Grade M25 mix.

Concrete Initial Setting Time :

Concrete Grade details like M25, Initial Setting Time, Block making Machine & Road Construction

Concrete initial setting time is that time from which the water is added to cement till the time at which 1 mm square section needle does not penetrate the cement paste. This can be easily done with any grade like Concrete Grade M25.

Cement TypeConcrete Initial Setting Time
High alumina30
Super sulphated30
Low heat60
Masonry cement90

Concrete Block Making Machine :

Concrete Grade details like M25, Initial Setting Time, Block making Machine & Road Construction

Concrete block making machine comes in different specifications like output of number of blocks per hour, different size of blocks, cycle time etc. It all depends on the requirement and scale of the project. It come in a option of Manual and Hydraulic. A good Concrete block making machine comes at a value from Rs. 2,50,000.00 to Rs. 4,50,000.00 as a good startup cost. You can use any grade like Concrete Grade M25 which is a too overwhelmed grade. Sample specification is as follows:

Brick TypeSolid
Automation GradeSemi-Automatic
Capacity (bricks per hour)500-1000
MethodHydraulic Pressure

This sample is of is heavy duty model an egg laying type hydraulic operated Machine. It will lay block on the concrete Floor and move to the next laying. Any type of concrete blocks can be produced with Consistent quality , high strength and pressure with accurate sizes by fixing different types of concrete mould and ram in the machine.

Total Power7 H P
`3 Phase 415 V 
Hydraulic Motor3 H.P 1440 rpm
Vibrator Mould Motor2 H.P 2880 rpm
Vibrator Ram Motor1 H.P.2880 rpm
Travel Motor1 H.P 1440 rpm
Weight1600 kg (Approx)
Operating Pressure140 kg/cm³
MethodHydraulic Pressure
Warranty1 Year
Motor MakeKirloskar/Crompton/Havells
Hydraulic Cylinders2
Hydraulic Tank25 Litres
MaterialMild Steel Vizagukku Brand
Block TypeSolid/Hollow
Interchangable mouldYes
Production capacity 50-60 stroke/hour

Concrete Road Construction :

Concrete road construction has been used extensively for paving highways and airports as well as city internal roads. These pavements are of 3 types:

  • Jointed Plain Concrete Pavement (JPCP)
  • Jointed Reinforced Concrete Pavement (JRCP)
  • Continuously Reinforced Concrete Pavement (CRCP)

The thicknesses typically range from 200mm to 400mm for roadways and highways, depending on traffic, environment, soils. Stresses due to temperature variations and loading are the primary factors in deciding the thickness of road. Steps in the Concrete road construction are as follows :

  • Preparation of sub-base
  • Placing form work
  • Batching materials
  • Concrete Grade Design mix
  • Preparation of mix
  • Laying the mix
  • Compaction
  • Joints
  • Finishing the surface
  • Curing