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Selecting a brand of cement

By Jayantha Bandara

The writer is a Civil Engineer who counts over 10 years' experience in the field. He specializes in cement and concrete structures. He has also delivered over 100 presentations to professionals including fellow Civil Engineers, Architects, Contractors and students in various educational institutions.

When a consumer is faced with the task of purchasing cement, it is more often than not the case that he would have to make his purchase decision in the absence of proper information. This is an unfortunate situation given the large amount of money one has to dole to purchase a commodity such as cement. More unfortunate is that cement used to construct houses and buildings which are expected to last a lifetime, if not many generations, whereas a washing machine which may last about 10-15 years is bought after considering a greater amount of information.

This article attempts to provide information that would assist to make a prudent decision in selecting a brand of cement. It also addresses some myths and fallacies that are commonplace in the hardware industry. In a house-building scenario, approximately 15% of the total cost is spent on cement. However, at the time of spending, consumers are often dissatisfied with having to spend what seem to be large amounts of money, on a commodity such as cement. There are also many fallacies and myths in the market place, which add to such dissonance.

Any house builder will want to live in a strong home, without any cracks, leakage or damages. Thus, the selection of a cement brand of superior quality is the first high priority and a lot of attention. There are many categories of cement available in the market (not to be confused with brands), of which Ordinary Portland Cement (OPC) is the most commonly available and suitable type for general construction purposes such as concrete mortar or plaster. Among the other categories of cement available in the market at present is masonry cement. This type is not suitable for concrete and other heavy duty activity.

From a consumer's point of view, there are many areas he needs to be comfortable with, when making a purchase. The date of manufacture is of great importance.

As a general rule, cement, which has been packed most recently, stands to serve well. Consumers should be careful of any cement, which has been packed beyond eight weeks of the purchase date. It is a legal requirement that the date of packaging is printed on the pack.

Besides the date of packing, it would be prudent to consider the physical properties when selecting a brand. Of the physical properties, compressive strength is of foremost importance. Compressive strength refers to the ability of a particular brand of cement to withstand a load. Cements of superior quality will exhibit high compressive strength and more importantly, the level of strength will remain constant throughout. Some brands available in the market today may indicate high levels of compressive strength when tested, but these levels will fluctuate when cements of different manufacturing dates are tested.

A house that is built with a cement of high compressive strength is likely to have a longer life period, i.e. durability of the building. A house is normally intended to last at least 100 years. Today it is very common to build a two-storey or multi storey houses with concrete slabs, beams and columns. The compressive strength of cement used to cast these elements needs to be sufficiently high to be able to resist the load during the lifetime of the building.

Cement that has 28 days compressive strength of at least 50-60 Newton per square millimetre (N/mm2) will be ideally suited for such construction.

Consumers who are interested in knowing the compressive strength of a brand can ask the manufacturers to produce independent test reports which shows strength results, as well as specified limits by Sri Lanka Standards Institution. In case of a multi storey buildings, this information would be very valuable and of great importance, even if it is a well-known brand to judge the quality of cement supplied to site. Compressive strength of cement can also be tested at any cement testing laboratory.

Another important property one has to look for in cement is fineness. The finer the cement, the better it will perform. The fineness of a cement is extremely significant because cement is always mixed with water and its speed of reaction depends predominantly on the fineness.

Fineness of cement is different from brand to brand. But it can be easily detected by visual appearance. Cement which is finer will have a large volume and the cement bag will appear to look bigger. Cement manufacturers who adopt new manufacturing technology produce cement, which is not only high in fineness, but also consists of well-graded cement particles. This gives overall high performance.

There are other important physical parameters such as setting time of cement but compressive strength and the fineness are the more related physical parameters from a consumer's point of view.

www.eagle.com.lk

Crescat Development Ltd.

www.helpheroes.lk


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