Importance of Steel Reinforcement in Concrete Slab

Importance of Steel Reinforcement in Concrete Slab

Posted By: Fundi Mjanja on 31st of October 2013

People have most often misunderstood the importance of steel reinforcement in concrete structures.  Most laymen in the construction industry are unaware that there is no substitute for concrete steel reinforcement in a structural building. The design/construction principal being responsible to the owners of the building project has a professional and moral responsibility to ensure that there are no substitutes for specified materials in the in the construction project. Contractor-Client conflicts over failures which arise because of plain concrete slabs are being reported more frequently than ever before. More often than not clients complain of being shortchanged by the contractors as they are not getting what was promised in the way of protection from wide cracks, the surface quality is poor and difficult to finish, and incurring excessive maintenance costs in repairing unravel joints and cracks. Clients end up spending a lot of money, either in tearing up and replacing with steel reinforced concrete or placing additional concrete topping to repair the poor quality surfaces. Concrete slab without reinforcement steel always result into extensive cracks over -time causing structural weakness.  Concrete steel reinforcing has been in the construction marketplace over 100 years, and it has never disappointed whenever it is used properly.  While most construction workers know that all steel reinforcement must be properly positioned in the concrete and be provided with sufficient cover, some steel ends up in the wrong place. In a slab on grade (ground slab on top of stable compacted hardcore fill) with one layer of reinforcement, the bar mats should be placed on supports which are 1/3 the depth from the top of the slab or a minimum concrete cover of at least 51 mm. Construction experts believe that the steel area should be reduced or terminated with slip steel dowels at construction joints to allow for free contraction and load transfer at those locations. This is a good measure especially where large concentrated loads are applied to floors. So what is wrong with just using plain concrete slabs and paving without incorporating reinforcement steel? All concrete will crack at some point due to some shrinkage that take place at control and construction joints, but many times you will find out that the slab has already “decided” to crack more randomly or at intermediate locations. If the steel reinforcement is left out and the sub-grade settles there is nothing to prevent the cracks from widening when the slab settles.