Types of Bricks and Details

Arrangement of bricks continuously in a row or horizontal way is known to be course. Depending on the arrangement of bricks there are some types of course.

Stretcher course – When the long and narrow faces of bricks are arranged in the direction of the length of wall, then that course is called as stretcher course. The narrow and lengthy faces of the bricks are seen from the front elevation of the course.

Header course – When the shorter faces of bricks are arranged in the direction of the length of wall, then that course is called as header course. The front elevation of header course resembles the shorter faces of the bricks.

Soldier course –When the long and thin faces of bricks are arranged in the direction of the length of wall, then that course is called as solider course. The front elevation of solider course resembles the long and thin faces of the bricks.

Sailor course – Same as soldier course but the difference is here, long and thick faces of bricks are visible from front elevation of this type course.

Rowlock course –When a 90 degree turn is applied to the header course front elevation, the rowlock course is achieved.

Shiner course – When a 90 degree turn is applied to the stretcher course front elevation, the shiner course is achieved.





Types of bricks

Types of bricks depending on their manufacturing method. The bricks are type Burnt bricks, Sundried bricks etc.

Burnt Bricks

By burning the brick mould with the mixture in the kiln, the burnt bricks are produced. These are the commonly used bricks in the construction field as they possess some good qualities or properties. These burnt bricks further classified into 4 different types namely, 1st class, 2nd class, 3rd class and 4th class.


Sun-dried bricks or unburnt bricks

Sun-dried or unburned/unburnt bricks are moulded/molded and let-to dry in sunlight instead of burning them in a kiln or clamp. These types of bricks are not enough strength, less fire & water resistance. Widely these types of bricks are not used in construction but sometimes this type used to construct cheap & temporary structures.

Details and Type of contracts

The contract is various types, for execution of civil engineering works. The contract are
» Lump Sum or Fixed Price Contract
» Measurement contract
» Turnkey Contract
» Design and BuildCost Plus Contracts
» Unit Price Contracts
» Time and Material ContractsItem rate contract
» Percentage rate contract
» Labour contract
» Piece-Work agreement
» Target Contract

1. Lump Sum or Fixed Price Contract :-

 The contractor agrees to perform the work specified and described in the contract for a fixed price. The price of a fixed contract can only be changed upon the execution of a change order, under which the owner and the contractor either

2. Measurement contract :-

A measurement contract might also be appropriate on projects where the design has not been completed in sufficient detail for bills of quantities to be produced.It should be possible to describe the works in sufficient detail to determine a programme and to  obtain rates from tenderers.  Generally tenderers rates will be based on drawings and approximate quantities.

3. Turnkey Contract :-

A turnkey contract is a business arrangement in which a project is delivered in a completed state. Rather than contracting with an owner to develop a project in stages. The developer is hired to finish the entire project without owner input.

4. Design and Build :-

Design and Build procurement works on the basis that the main contractor is responsible for undertaking both the design and construction work on a project, for an agreed lump-sum price. Design and build projects can vary depending on the extent of the contractor’s design responsibility and how much initial design is included in the employer’s requirements.

5. Cost Plus Contracts :-

The Cost Plus Contract is a type of a construction contract under which the owner agrees to pay the complete cost of the materials and labor needed to needed to build the project along with a fee for the contractor’s overhead and profit. This contract type is favored where the scope of work is highly uncertain or indeterminate and the type of labor, material, and equipment needed to build the project is also uncertain in nature.

6. Unit Price Contracts :-

Unit Price Contracts are based on anticipated quantities of items which are counted in the project in addition to their unit prices. The final price of the project depends upon the quantities required to carry out the work. Generally, these types of contracts are suitable only for construction and supplier projects which involve accurate identification of different types of items, but not their numbers, in the contract documents. These types of contracts are oftentimes used on excavation projects.

7. Time and Material Contracts :-

Time and Material Contracts are usually preferred if the project scope is not clear, or has not been defined. The owner and the contractor must establish an agreed hourly or daily rate, including additional expenses that could arise in the construction process. The costs must be classified as direct, indirect, mark-up, and overhead. Sometimes the owner might want to establish a cap or specific project duration to the contractor that must be met, in order to have the owner’s risk minimized.

8. Item rate contract :-

For this contract, contractors are required to quote rates for individual items of work on the basis of schedule of quantities furnished by the client’s department.

9. Percentage rate contract :-

In this form of contract, the client’s department draws up the schedule of items according to the description of items sanctioned in the estimate with quantities, rates, units and amounts shown therein.

10. Labour contract :-

This is a contract where the contractor quotes rates for the item work exclusive of the elements of materials which are supplied by the client’s Department.

11. Piece-Work agreement :-

This is that for which only a rate is agreed upon without reference to the total quantity of work to be done or the quantity of work to be done within a given period.

12.Target Contract :-

This is the type of contract where the contractor is paid on a cost-plus percentage work performed under this contract. In addition, he receives a percentage plus or minus on savings or excess effected against either a prior agreed estimate of total cost or a target value arrived at by measuring the work on completion and valuing at prior agreed rates.

Factors Affects Air Content of Concrete

Concrete air entrainment is not an easy process since it is influence by several factors. These factors shall be properly investigated to be able to obtain designated air entrainment.

Factors Affecting Air Content of Concrete

» Water content
» Fine aggregates grading
» Coarse aggregates
» Temperature of concrete
» Mixing action of concrete
» Use of admixtures other than air entrained admixture
» Cement content of concrete
» Fly ash content
» Vibration or compaction of concrete

1. Water Content :-

Increase of water content in the mixture will lead to increase concrete air content and vice versa. This is because the increase of water content would increase fluid mixture into which air bubbles could be integrated easily through mixing operation. Hard water such as well or quarry water, which contain minerals, would reduce air content if they are used to dilute air entraining admixture.

2.  Fine Aggregate Grading :-

Air entrainment will be carried out easily as the percentage of fine aggregate is increased. Fine aggregate sizes ranges from sieve No. 30 to sieve No. 100 will create small voids that can contain air bubbles. However, other fine aggregate sizes will require greater quantity of air entraining admixture to reach the same air content.

3. Coarse Aggregate :-

Presence of dust on coarse aggregate surface decreases air content. Crushed aggregate would entrain lesser air compare with gravel aggregate.

4. Temperature :-

For constant amount of air entraining admixture, the increase of temperature will lead to decline concrete air content. So, if temperature varies considerably during mixture production, it would be required to adjust air entraining admixture to achieve designated air content. Temperature reduction from 21C to 5C will increase air content by 40% whereas increase of temperature from 21C to 38C will decline air content by 25%.

5. Mixing Action :-

Air content increase by mixing for up to 15 minutes and mixing beyond this time will decrease air content. Entrained air will vary with type, physical condition, speed of the mixer and quantity of concrete that is being mixed. Seriously worn mixer will increase difficulty of air entrainment operation. Similarly, mixer with significant amount of hardened concrete buildup on mixer blades or in a drum increase air entrainment operation.

6.  Admixtures other than Air Entrained Admixture on :-

There are number of admixtures that have air entraining capacity for example retarding admixture and water reducing admixture. So, smaller quantity of air entraining admixture will be needed when these admixtures are also provided in the mixture.

7. Cement :-

Air content of concrete reduces with the increase of cement fineness. For the same air content, concrete produced using Type I cement need considerably lesser quantity of air entrainment admixture compare with concrete made with Type III cement.

8. Fly Ash :-

Air content reduces as the fineness or surface area of fly as increases. Increase of fly ash per unit concrete reduces air content of concrete and increase in fly ash carbon content reduces concrete air content.

9. Vibration :-

Vibration reduces concrete air content. For example, half of air content will be lost if vibration is applied for more than three minutes.