Colour of cement does not play any role in its performance. Appearance of colour purely depends upon the percentage of addition of a particular raw material which goes in the manufacturing of cement.
A ball of cement paste should be made and kept in a shaded environment for 24 hours. If it hardens then cement is good.
Blended cements (PPC) perform better than OPC in Indian climate and weather.
Colour of cement has got no bearing on its strength and durability.
Any cement is governed by initial setting time and final setting time. Indian standards have specified certain timings for these. Initial setting time of cement should not be less than 30 minutes while final setting time should not be more than 600 minutes.
Strong, durable, right setting time and uniform size distribution.
Concrete is a mixture of cement, sand, stone aggregates and water.
A concrete member in which reinforcement is also placed is known as a Reinforced Cement Concrete member (R.C.C.)
Mortar is a mix of cement, sand and water, to be used for brickworks/block works and plaster.
Normally, the amount of water that is required per bag of cement is 21 – 25 litres only.
Quality of cement has nothing to do with its colour.
1:1.5:3, where 1 part of cement is to be mixed with 1.5 parts of sand and 3 parts of coarse aggregates. Ideal water requirement for the mix should be 20 litres per bag of cement.
The ways in which concrete may be spoilt are many, most common of them being:
Freshly prepared mortar at site has to be consumed within 15 to 30 minutes. Same goes with concrete consumption, if concrete is prepared at site. However, concrete prepared in ready mix plants can be used after 2 to 3 hours also because concrete in ready mix plants is manufactured as per specific requirements and controlled conditions.
Compaction is essential in order to properly compress the concrete by removing entrapped air inside it. If compaction is not done properly then the strength of concrete will be compromised.
The concrete is liable to become weaker and more prone to seepage.
Sand volume should be increased and the water volume should be reduced with some approximation.
It results in heavily segregated concrete
Steel bars are placed because concrete is weak in tension
Curing of Concrete is a method by which the concrete is protected against loss of moisture required for hydration and kept within the recommended temperature range. Curing also increases the strength and decreases the permeability of hardened concrete.
Walls: Water should be sprinkled on masonry walls twice a day for 7 days
Water Ponding, periodical sprinkling of water, covering R.C.C. member with a wet hessian cloth, sprinkling of curing compound which hardens to form a thin protective membrane, are some of the methods by which concrete can be cured.
Curing should be started just after the R.C.C. surfaces begin to harden. Curing should be done for a minimum of 7 days.
Ideal curing period in case of concrete as well as mortar is 7 days
Best method for curing sloped slab is covering it with wet hessian cloth and periodically sprinkling water on it for a period of 7 days.
Formwork is the term used for the process of creating a temporary mould into which concrete is poured and formed. Traditional formwork is fabricated using 18mm thick plywood, but it can also be constructed from steel, timber and other materials.
Camber in the upward direction is provided in the formwork for horizontal members to counteract the effect of downward deflection which will be caused due to the weight of reinforcement and concrete placed over that.
Shuttering boards/Planks should be properly oiled or greased with Deshuttering oil before the placement of reinforcement. The oil film sandwiched between concrete and formwork surface not only helps in easy removal of shuttering but also prevents loss of moisture from the concrete through absorption and evaporation.
Indian standard IS: 456 has given a timeframe for stripping of formwork for different R.C.C. members when sufficient curing is done and ambient temperature is more than 15°C. Details are given below:-
Column casting should be done upto beam bottom (i.e. 8 feet) in one lift under normal circumstances when floor to floor height is 10 feet.
Procedure of deshuttering a cantilever slab remains same as regular slab. But props will have to be kept for a minimum of 14 days for span less than 4.5m and 21 days for span more than 4.5m.
Steel reinforcement also known as rebars are made of different diameters and come in 6m and 12m lengths. They are provided in conjunction with concrete to make the member strong. Any member will be subjected to compressive as well as tensile forces. Concrete helps in resisting compressive forces whereas steel reinforcement helps in resisting tensile forces.
Bar-bending-schedule is a format used to calculate exact requirement of reinforcement in a particular project.
Steel reinforcement is available in various sizes and grades (yield strength). There are 4 different grades of reinforcement that can be used in construction. They are Fe250, Fe415, Fe500 and Fe550. Number denotes the yield strength of reinforcement in N/mm². Fe500 is most widely used nowadays because it gives high yield strength and design becomes economical by the use of Fe500 reinforcement. Bars of various diameters are available in markets from 8mm to 40mm. Diameter of the bar used at site should be as per structural design requirements.
Cover blocks are provided between the formwork and reinforcement. Main purpose of providing cover block is to protect reinforcement from getting exposed to atmosphere and in turn protect it from getting corroded. Indian Standard IS:456 suggests use of different size of cover for different elements and different hours of fire resistance.
Yes. You can receive the test certificate of the batch of materials supplied at our site. The certificate will confirm the compliance of the quality of supplied materials as per the requirement of relevant Indian Standard Code.
Normally, the bricks are tested for compressive strength, water absorption, dimensional tolerances and efflorescence. However, at small construction sites, the quality of bricks can be assessed based on the following, which is prevalent in many sites.
The following precautions should be taken:
The brickwork should be cured with water and kept moist for a minimum 7 to 10 days period for proper development of strength.
Dry bricks will absorb water from the cement mortar and make the joints of brickwork weak.
Plaster protects the structure from temperature variations, external attacks of sulphates, chlorides, etc. Plaster also provides smooth & aesthetic surface on RCC & Brickwork surface.
The following precautions should be taken:
For inside wall plaster it is 1 cement : 6 medium sand by volume and the thickness should not be more than 12 mm. For ceiling plaster it is 1 cement : 3 medium sand by volume and the thickness should not be more than 6 mm.
There are many options like copper/brass pipes, galvanized iron (GI) pipes, plastic pipes, etc. However, GI pipes are more commonly used in India. But PVC pipes should be used as they can be easily replaced during repairs.
Only small-diameter pipes used for the supply of water for domestic purpose can be concealed. During the laying of pipes, care should be taken to see that the nodes or the joints are properly fixed without any chance of leakage. But it is always recommended to conceal pipes only in unavoidable situations and limit it to small lengths.
Following precautions would be necessary before painting the internal surface of the house:
Cracks will appear at the junction of door frame and joints if lintel is also not provided above the opening.
The following precautions should be taken for safety and quality purposes:
Use of RCCB/ELCB (Residual Current Circuit Breaker / Earth Leakage Circuit Breaker) prevents accidental shocks and also keeps a check on the earthing system of the house. In case of leakage of very small current in milliamperes, the circuit would trip and prevent the mishap.
Earthing is required to bypass the overrated current caused due to fluctuation in circuit parameters such as phase-frequency, line voltage, etc., to save human life and electrical assets from short circuits.
No, the concealed wiring will not weaken the concrete structure