Collapsing Buildings and the wrong use of Cement

The spate of collapsed buildings in Nigeria’s cities has become alarming. This has given everyone a cause for worry. Prior to this time, the issue of collapsed buildings was associated with old mud houses which had become weak and were unable to stand any form of stress or tension. Back in those days, there used to be a general belief that any house or structu

re built with cement block is not collapsible, except unless it is deliberately demolished.

Owing to this popular belief, it has become an irony as we see seemingly well structured and physically healthy buildings collapse like the great walls of Jericho. Some of these buildings are either still under construction or already in use for residential or commercial purposes.

Many lives and properties worth millions of naira have been lost to different collapsed buildings in the country. Cases of homelessness have been recorded in great measures. Some survivors now have psychological trauma as they have lost dear ones while some have lost all they had laboured for. There are also victims who have been forced to relocate and start life all over, while others have taken to social vices as a result of frustration.

Following the enormous trauma heaped on its victims by the issue of building collapse, experts are now raising some  questions about the standard of cement in the Nigerian market. If cement is a fine powder that, when mixed with water, becomes solid, it is then quite very probable that substandard cement has flooded the Nigeria market leading to the erection of weak structures at the peril of innocent occupants or workers on site.

Responding to the question of standard of cement in the country recently, Dr Joseph Odumodu, Director General of the Standards Organisation of Nigeria (SON), cleared the doubt, saying that there is no sub-standard cement in the Nigerian market but intoned that people may be misapplying cement. He disclosed that the Honorable Minister of Industry, Trade and Investment, Mr Olusegun Aganga, recently announced the adoption of new standards for the use of cement and expressed SON’s resolve to implement the new policy.

Inquiry showed that Ordinary Portland Cement (OPC), which is the most commonly used cement, comes in different grades: 32.5, 42.53, 52.5 and 53-S (Sleeper Cement) and every grade is meant for a particular type of construction work. Grade 32.5 is suitable for plastering; grade 42.5 is appropriate for concrete, brick masonry, plastering, pointing, flooring and general construction works. Grade 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.

The cement grade is determined by measuring its strength after 28 days. If the strength is less than 33N/mm2 after 28 days, then it is grade 33 cement; If it is between 33 to 43 N/mm2 after 28 days then it is 43grade cement and if it is between 43 to 53 N/mm2, it is 53 grade cement.

One question that should concern us is: do our site guys, ranging from the common labourers to the site supervisor who is most likely going to be a graduate of civil engineering know the different grades of cement and their appropriate usage?  From all indications, it seems not. The misuse or misapplication of cement grades in Nigeria is largely due to ignorance or inadequate enlightenment. The 35.2 grade cement manufacturers and their distributors do not educate their customers on the appropriate use of their products but leave these uninformed buyers to their fate.

Another reason for abuse of cement is economic. A site supervisor recently told me that, “as much as one thinks of the strength of the building, one should also think of the economy.” I was shocked to hear this from a site engineer and it dawned on me that most of the site contractors are more after the profit they will make than delivering a standard building for safe habitation.

I was disappointed as I got a clearer picture of the caliber of site contractors and supervisors we have as professionals. The mediocrity has to be changed, there has to be proper implementation of the new policy on cement standardization to ensure the appropriate use of cement. Who will steer this ship? Regulation bodies like SON, Cement Manufacturers Association of Nigerian (CMAN) and others have to rise to the task of ensuring safety in building construction.

For these reasons, it only makes sense for the harmonization of the cement standard in the country to 42.5 and an outright ban of the 32.5 grade of cement. This is the best way out of the danger posed by this misuse/misapplication of cement grades in Nigeria. This is the way most other countries of the world have dealt with the issue of poor implementation of cement standards in their climes.

The issue of cement standardization is just a step to ameliorating the menace of building collapse in our cities.  There should be proper check at work sites to ensure that cement is applied based on the approved standard. Regulators should not fold their arms after setting the required standard but should make efforts to ensure strict adherence by contractors. The general public should understand the grades of cement and their right application in construction works.