Importance of Steel Reinforcement in Concrete Slab 2

Importance of Steel Reinforcement in Concrete Slab 2

Posted By: Fundi Mjanja on 7th of November 2013

The real questions become:  How can one guard against wide cracks and help maintain aggregate interlock, keeping the slab in one plane? The only answer is to use steel reinforcement. With concrete steel reinforcement the slab thickness is reduced by just replacing the strength of a thicker slab with the strength of the steel. Once there is a well-graded and compacted sub-base, one may want to consider the strength of steel reinforcement as contributing to the moment capacity of slabs and paving. Considerable area of steel reinforcement is necessary to provide structural support for the un-cracked concrete but when dealing with cracked concrete slabs and paving on grade (since the concrete is usually well supported uniformly) only properly positioned steel reinforcement in concrete will greatly improve the structural performance. To develop an area of steel for a reduced cross sectional area of slab or paving—say 1inch (25 mm) or 2 inches (50 mm) difference—we can use the difference in the cracking moments of two slab thicknesses and say the moment capacity of the steel reinforcement will replace the difference in the two moment capacities of the concrete. Even single layers of steel reinforcement will provide the reserve strength to maintain the thicker slab loading after the concrete cracks. As a bonus steel provides the necessary temperature and shrinkage protection as well as crack width control. It is also important to note that fewer control joints can be a consideration when steel reinforcement is used. Benefits of steel reinforced concrete slabs Here are the benefits of steel reinforced concrete slabs: Steel reinforcing is simple to place Steel reinforcing reduces random cracking Steel reinforcing reduces and controls crack width and helps maintain aggregate interlock Displacement and curling can be minimized when steel reinforced concrete is used Strength is increased with steel reinforced concrete—even the smallest cross sectional area of steel reinforcement will provide considerable reserve strength Finally admixtures are not an alternative to steel reinforcement as they both perform different roles in the concrete. Therefore, admixtures cannot be substituted for steel reinforcement and vice versa. The steel reinforcement industry is dedicated to providing quality steel reinforcement to the construction industry. It is essential to have a well-graded and compacted granular sub-base and the steel reinforcement sized, spaced, and placed properly. Of course, total quality can only be achieved when well qualified contractors and workmanship is employed on the construction site.