Some major cement ingredients and their uses

Cement is considered as strong binding material for building construction. So, there should be proper knowledge on the composition of cement. The functionality of cement constituents plays a major role for cement composition. To attain the superior quality of cement, the amount of constituents should be modified at the time of producing cement.

Formation of Cement - The following constituents are part and parcel of cement. Given below, the common percentage of these constituents in cement:

Constituents : Percentage in cement

Lime 60-65
Silica 17-25
Alumina 3-8
Magnesia 1-3
Iron oxide 0.5-6
Calcium Sulfate 0.1-0.5
Sulfur Trioxide 1-3
Alkaline 0-1

Functions of Cement Constituents - Given below, the detail characteristics of these constituents :

Lime: Lime stands for calcium oxide or calcium hydroxide.
The existence of lime should be adequate to develop silicates and aluminates of calcium.
Inadequacy in lime minimizes the strength of property to the cement.
Inadequacy in lime leads to quick setting of cement.
Surplus in lime quantity makes cement weak.
With the existence of lime excessively, cement will be inflated and decomposed.
Silica: Silicon dioxide is called as silica, chemical formula SiO2.
There should be adequate quantity of silica in cement to dicalcium and tricalcium silicate.
Silica contributes strength to cement.

Normally, the percentage of silica is about 30 percent in cement.

1. Alumina: Alumina is Aluminium oxide. The chemical formula is Al2O3.
a. Alumina contributes rapid setting property to the cement.
b. Clinkering temperature is reduced with the existence of the necessary quantity of alumina.
c. Excess alumina makes the cement weak.

2. Magnesia: Magnesium Oxide. Chemical formula is MgO.
a. Existence of Magnesia should not be in excess of 2% in cement.
b. The strength of the cement will be decreased significantly with excessive magnesia.

3. Iron oxide: Chemical formula is Fe2O2.
a. Iron oxide assigns color to cement.
b. It functions as a flux.
c. At a very high temperature, it imparts into the chemical reaction with calcium and aluminum to develop tricalcium alumino-ferrite.
d. Tricalcium alumino-ferrite brings hardness and strength to cement.

4. Calcium Sulfate: Chemical formula is CaSO4
a. It exists in cement in the form of gypsum(CaSO4.2H2O)
b. It delays or retards the setting action of cement.

5. Sulfur Trioxide: Chemical formula is SO3
a. It should not exist in excess of 2%.
b. Excess Sulfur Trioxide makes cement to become weak.

6. Alkaline:
a. It should not exist in excess of 1%.
b. Excess Alkaline matter leads to efflorescence.



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Rajib Dey
www.constructioncost.co
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Details of Sieve Analysis Method

Sieve analysis is conducted to establish the particle size distribution of the coarse and fine aggregates. This is performed with sieving the aggregates according to IS: 2386 (Part I) – 1963. Here, various types of sieves are applied as recommended by the IS code and then the aggregates are passed through them and thus the particles with different sizes are obtained which are abandoned on various sieves.

The following equipments are utilized for sieve analysis.

i) A set of IS Sieves of sizes – 80mm, 63mm, 50mm, 40mm,31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 6.3mm,4.75mm, 3.35mm, 2.36mm, 1.18mm, 600µm, 300µm, 150µm and 75µm.

ii) Balance or scale with a precision to calculate 0.1 percent of the weight of the test sample. The sample for sieving is created from the bigger sample either by quartering or with the help of a sample divider.

Sieving Test Method as per British standard

Materials Required
Specimen, sieve shaker, BS410 Standard sieves, 0.1g accuracy balance, oven, porcelain dish and spatula, receiving pan, cleaning brush and clock.

Method:
Cleanse the sieves of sieve shaker with cleaning brush to check whether any particles are blocked in the openings.

Note down the weight of each sieve and receiving pan.
Dry the specimen in oven for 3-4 minutes to obtain the dried specimen (overlook, if the specimen is already dried).
Weigh the specimen and note down its weight.

Place the sieves in such a manner that the smaller openings sieve remains to the last and larger openings sieve remains to the top. (Just, organize them to the ascending order of sieve numbers – No.4 sieve on top and no.200 sieve at bottom).

Retain the weight recorded specimen on the top sieve and then provide the complete sieve stack on the sieve shaker along with the lid and receiving pan.
Let the shaker to function 10-5 minutes – Utilize the clock here.
Detach the sieve stack from the shaker and note down the weight of each sieve and receiving pan individually.

Download the following sample sheet for sieve analysis.



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Published By
Rajib Dey
www.constructioncost.co
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Some vital construction documents for a construction project

If it is required to develop a new building or refurbish surviving property, the owner should have arranged a document so that the work & other portions of the construction project can be performed systematically. Each construction project should comprise of crucial documents that generally form the part of every construction contract.

In the design and construction part, various types of construction documents are utilized. Given below, some vital construction documents which should exist in every construction project.

1. Contract Agreements and Contracts: It should be utilized by the contracting officer (owner) as well as the contractor. It is considered as the vital part of the contract documents.

2. Statement of Work (SOW): A solid scope is very helpful throughout the bidding process and soon after throughout the construction sequence. A well-defined scope should have been utilized to define the amount of work necessary for the completion of work.

3. General Conditions: This contract document will be applied to determine the obligations and rights for accomplishing any project. This type of document also involve overhead costs, what to claim and your rights.

4. Special Conditions: It is normally an extension of the contract and supported with the general conditions. In this part, specific conditions and clauses to each particular project or job should be indicated. It provides special attention to particular instructions and requirements which are essential to give guidelines for executing the work in a perfect way.

5. Bill of Quantities: It is developed with the list of various trades, and materials which create the part of the construction. This document may not be essential for the contracting officer.

6. Drawings: In this document, there are all set of drawings which are essential to execute the part of the job. These drawings generally comprise of the latest drawings and should be under possession of the contractor before starting the project. It should contain all drawings from consultants and will compose the whole project being contracted.

7. CSI MasterFormat Outline: The technical requirements are described in this document to finish, carry out and/or perform each nominal task or material being included in the construction projects. It will add intelligence to the construction drawings; indicate common standards, deviations accepted, materials accepted and the compulsory testing for all materials. Normally, specifications are formed with referencing construction standards and codes.


8. Creating Construction Schedule: The construction schedule belongs to a significant piece of the document. In this part, the contracting office will be able to recognize how and when the project will be finished.

9. Costs in the Construction Industry: This document includes the break-ups of all items being incorporated in the construction project.

10. List of Common Types of Construction Insurance: It is treated as the vital part of the contracting officer as it will provide assurance to the owner that the contractor has the means and the financial support to execute the construction contract.



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Published By
Rajib Dey
www.constructioncost.co
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