By Kayode Olajiga
While the incidence of building collapse increases, same set of manufacturers and experts come up with new themes on how to explain away the shortcomings of the building sector. They bring up new ways to curb these incidences, organize seminars to sensitize the general public, blame substandard and shoddy planning, absolve the sector of blame (shifting it to a few bad, unregistered eggs) while, as usual in Nigeria, we move on and several more buildings join the queue. Maybe it is a conspiracy; maybe not!
The standards we have come to assume for buildings have come from proselytized views milking our ignorance. For someone like me who have never taken the ‘cement talk’ very serious except for the price conspiracy, it is important to share my newfound understanding. To some, it will be elucidative while to others – who understand a thing or two about it – it will support whatever knowledge they already have. Let’s shoot!
What exactly is cement? “Cement is a fine, gray powder which sets after a few hours when mixed with water, and then hardens in a few days into a solid, strong material.” Cement is made from the mixture of heated limestone, sand, clay and/or shale. Its usage as the major component in constructions means it has to be subjected to strict standards with each individual type/grade used according to the prescribed standards.
There are several types of cements with needs dictating their usage for specific purposes. Ultratech Concrete lists the types of cement as Ordinary Portland Cement 32.5, 42.53, 52.5 grade (OPC); 53-S (Sleeper Cement); Portland Pozzolana Cement (PPC), both Fly Ash and Calcined Clay based; Rapid Hardening Portland Cement; Portland Slag Cement (PSC); Sulphate Resisting Portland Cement (SRC); Low Heat Portland Cement; and Hydrophobic Cement.
Here, we are concerned with the OPC and its three main grades, namely, 32.5, 42.5 and 52.5 as they are mostly used in construction. The 32.5 grade OPC is suitable for general concrete works, block making and plastering where the structures are not taken to very high stresses. According to GharExpert, “It is not suitable where ‘Sulphate’ is in the soil or in the ground water”. 42.5 grade OPC on the other hand is notably “used in general civil engineering construction work i.e. brick masonry, plastering, pointing, flooring and in RCC Work”. 52.5 is used where high early strength in the first 28 days is required and it is basically utilized by builders of heavy infrastructure such as bridges, fly overs, large span structures and high rise structures where such structures take on high tensile strength.
There has been a raging storm in the country recently due to the request by professionals for Standard Organization of Nigeria (SON) to standardize the cement market. Cement is not cement as we were made to believe. There are instances where 32.5 grade OPC (that several professionals are bandying against) is the best; there are also situations where cement much lower in strength than 32.5 grade OPC is advised. Such examples are majorly in non-structural usage like masonry and plastering mortals.
The unique Nigerian terrain also ought to be considered. Here is where I identify with and accept these clamours. In a country where adherence to standardization is not a common language, where professionals and hired supervisors cut corners to maximize profit, it is important to have minimum cement grade strength. With all the seminars and sensitization campaigns that have gone into this exercise in the past, the result of such aggressive campaigns have not been seen as most building engineers resort to the cheapest grade in the market for building projects they are not suitable for.
Here is where SON’s 42.5 grade OPC standard makes the most sense. As we can see in the different usages highlighted earlier on, the 42.5 grade can effectively substitute in most cases where we may require the 32.5 grade.
Policies are not what we lack but the required will to effectively make these policies work. How do we enforce the 42.5 grade strength when all the needs of standardization have been taken care of? Who enforces standardization in manufacturing plants? Who supervises building constructions to ensure that the policy on right grades are adhered to (test case is our aviation industry where we still struggle with enforcement)? Are there plans to involve insurance companies (to request for all standardization documents before insuring a building)?
We should all understand that cement standardization is the first step in a long list of procedures aimed at stopping the incidences of building collapses that must be taken serious. The government shouldn’t go to sleep thinking the job is done with standardization as the real war on misapplication of standards starts then. The public must be effectively enlightened on the new standards; made to understand that this policy is about safeguarding their lives and properties and as such must buy wholly into it.
Remember that in building and construction, it is SAFETY FIRST! All other considerations follow.
Olajiga wrote from Lagos
