A Visual Scale of Concrete Deterioration A Visual Scale of Concrete Deterioration

A Visual Scale of Concrete Deterioration

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29 March 2018

CSC Services specialise in applying protective coatings that minimise deterioration of concrete. Properly applied, a protective coating can stop the deterioration of concrete before it progresses to reinforcing steel. Protection of this rebar is essential for the long-term durability of any concrete structure.

Coating deteriorated concrete is possible but it is considerably more difficult than coating new concrete. To do this effectively a contractor will need to consider the extent of deterioration and substrate condition. There are a range of tools available to assess this, but a contractor must understand the deterioration process to specify the optimum remedial solution.

As exposed reinforcing steel, rust staining and spalled concrete are all clear indicators of the loss of structural strength, a visual scale of deterioration can be used. Here Mick Flounders, CSC Services’ Contracts Director looks at some of the the key factors to look for and explains why…

Concrete deterioration
At the start of the deterioration process, concrete may look nearly new. If acid attack has occurred the deteriorated concrete can however be chipped easily.

Concrete deterioration
With initial surface deterioration some exposed aggregate will be present.

Concrete deterioration
Exposed aggregate will be widespread with advanced surface deterioration. There is likely to be moderate cracking too.

Concrete deterioration
As deterioration continues, lowering the pH of the concrete surrounding the reinforcing steel, rusting and spalling occurs, exposing the rebar. Rust staining will be evident and there will be significant cracking too. Hammer testing is widely used to identify rebar corrosion below the surface. Concrete that sounds hollow when struck may indicate a void.

Concrete deterioration
At the far end of the deterioration scale there will be widespread exposed aggregate. In addition, advanced surface deterioration with reinforcing deterioration can also be evident through widespread cracks and widespread rust staining.  

Refurbishment solution

Following the assessment of the concrete condition, the refurbishment solution can be specified. Typically cementitious or epoxy mortars are used to rebuild the concrete surface.

CSC Services have many years of experience installing cementitious coatings to reinstate concrete cover. There are a range of different coating products available depending upon substrate compatibility, life span and the film thickness required to provide the necessary cover.

CSC Services will often specify a waterborne, cementitious modified polymer coating. A 2mm coating is equivalent to 100mm of good quality concrete cover, and provides a complete barrier to water under 10 bar pressure. Being cement based, it chemically reacts with the substrate to form an integral part and will have a design life equivalent to that of the concrete to which it is applied.

Not only does this high performance cementitious coating reinstate cover it provides structures with additional protection against freeze/thaw cycles, de-icing salts, water and chloride ion penetration, thus ensuring that the life span of the structure is both achieved and extended.

Call CSC Services today on 0191 410 3444 for more information about concrete repairs or cementitious coatings.