The Effect of Sulfates on Reinforced Concrete Driveways And Balancing Reinforcement

Shane Reinforced Concrete Driveways 0 Comments

This article discusses the effects of one cause of reinforced concrete driveway damage and how it’s essential to balance the reinforcing of any concrete driveway. Scientifically expressed as SO4, Sulfates are found in soil, in reinforced concrete driveways and also in groundwater. If found in concentrated amounts, sulfates can create a chemical reaction with Portland cement inside a reinforced concrete driveway leading to the creation of expansive by-products like ettringite or thaumasite, this can also cause early failure of the concrete driveway slab.

Some of the most common negative effects happen on concrete slabs as well as foundation walls at grade wherein the sulfate ions, through cyclic exposure to wet and dry conditions, may create even more sulfates. When the amounts get higher and higher, the damage inflicted on the Portland cement material gets worse and eventually we get a collapse concrete driveway.

The Definition Of Some Terms Used In Reinforced Concrete Driveways

Reinforced concrete driveways can be flexible during a bending action, these results in a small curvature of the slab. Placed at the outer or tensile face of the bend is where the concrete undergoes tensile stresses, while the other compressive face endures the compressive stresses of the bending action like when a heavy truck is parked on the driveway.

The singly reinforced concrete driveway is a concrete product in which the concrete component is just reinforced at the tensile portion and the reinforcement, known as tension steel, is created to be tension resistant even when under heavy loads.

Concrete driveways with double reinforcement are concrete products that have tensile reinforcing materials on the concrete component are likewise reinforced at the compressive face to aid the concrete become compression proof. Compression steel is the name of the reinforcing material added later on. If the compression area of the reinforced concrete driveway is not enough to be compression proof during the tension action then more reinforcing material has to be given if the designer has made the size and diameter of the concrete portion smaller or limited in some way.

A reinforced concrete driveway which doesn’t contain sufficient reinforcing material is one in which the stress capability of the tensile reinforcing materials is lesser compared to the combined compression resistance of the concrete along with the compression steel in an under-reinforced tensile face. When the reinforced concrete part undergoes progressive bending actions, the stress on the steel becomes pliable whereas the concrete will not attain eventual failure.

Because the tension steel remains pliable and expands, the under-reinforced concrete driveway likewise bends in a ductile manner, displaying big damage which is the warning prior to its final failure and possible collapse. For these cases the bending tension of the steel dictates how the reinforced concrete driveway will be designed.

An over- reinforced concrete driveway is a concrete product in which the tension ability of the steel is greater than the combined compression ability of the reinforced concrete and the compression steel which has been reinforced too much at the tensile area. Hence, the excessively-reinforced concrete driveway will get damaged when the crush of the compressive-zone concrete and prior to when the tension area steel bends, such failure will not give out any warning signs prior to failure since it will come simultaneously.

Now a reinforced concrete driveway deigned and constructed correctly is the one with both the compressive and tensile areas being able to achieve bending while simultaneously imposing a load bearing on the reinforced concrete driveway effectively.

A design like this also has a potential danger as reinforced concrete driveways with too much reinforcement, since concrete failure is very fast as the concrete crushes simultaneously with the bending of the tensile steel and eventually gives way and this provides only a small indication of attaining complete concrete failure due to too much tension on the reinforced concrete driveway.

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