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 :
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 Grade | Mix Ratio (cement : sand : aggregates) | Compression Strength | Use | |
| Basic Concrete Grade | ||||
| M5 | 1 : 5 : 10 | 5 MPa | PCC | |
| M7.5 | 1 : 4 : 8 | 7.5 MPa | PCC | |
| M10 | 1 : 3 : 6 | 10 MPa | PCC | |
| M15 | 1 : 2 : 4 | 15 MPa | Bedding | |
| Medium Concrete Grade | ||||
| M20 | 1 : 1.5 : 3 | 20 MPa | RCC | |
| Concrete Grade M25 | 1 : 1 : 2 | 25 MPa | RCC | |
| M30 | As Per Mix | 30 MPa | RCC | |
| M35 | As Per Mix | 35 MPa | RCC | |
| M40 | As Per Mix | 40 MPa | Commercial RCC | |
| M45 | As Per Mix | 45 MPa | Commercial RCC | |
| High Concrete Grade | ||||
| M50 | As Per Mix | 50 MPa | Commercial RCC | |
| M55 | As Per Mix | 55 MPa | Commercial RCC | |
| M60 | As Per Mix | 60 MPa | Commercial RCC | |
| M65 | As Per Mix | 65 MPa | Commercial RCC | |
| M70 | As Per Mix | 70 MPa | Commercial 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 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 Type | Concrete Initial Setting Time |
| OPC(33) | 30 |
| OPC(43) | 30 |
| OPC(53) | 30 |
| SRC | 30 |
| PPC | 30 |
| PSC | 30 |
| High alumina | 30 |
| Super sulphated | 30 |
| Low heat | 60 |
| Masonry cement | 90 |
Concrete Block Making Machine :
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 Type | Solid |
| Automation Grade | Semi-Automatic |
| Capacity (bricks per hour) | 500-1000 |
| Method | Hydraulic Pressure |
| Material | Cement |
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.
| 906 MODEL | TRIPLE VIBRATOR |
| Total Power | 7 H P |
| `3 Phase 415 V | |
| Hydraulic Motor | 3 H.P 1440 rpm |
| Vibrator Mould Motor | 2 H.P 2880 rpm |
| Vibrator Ram Motor | 1 H.P.2880 rpm |
| Travel Motor | 1 H.P 1440 rpm |
| Weight | 1600 kg (Approx) |
| Operating Pressure | 140 kg/cm³ |
| Method | Hydraulic Pressure |
| Warranty | 1 Year |
| Condition | New |
| Motor Make | Kirloskar/Crompton/Havells |
| Hydraulic Cylinders | 2 |
| Hydraulic Tank | 25 Litres |
| Material | Mild Steel Vizagukku Brand |
| Block Type | Solid/Hollow |
| Interchangable mould | Yes |
| 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