Concrete Testing

The main difference between chloride concrete testing and carbonation concrete Testing is the type of substance which is being tested. A carbonation test of concrete uses a phenolphthalein indicator, which is sprayed onto the concrete structure. This intrusive investigation will indicate the depth of carbonation. Whereas Concrete Chloride Testing involves testing for the level of chloride content, this is obtained a taking a dust sample from the concrete structure by incremental drilling. The dust sample is submitted for laboratory analysis. The methodology can vary between each test, but this is dependent on the structure and environment.

Concrete Testing is vital to understand the safety and condition of an infrastructure asset. Concrete can be damaged by various factors such as: Corrosion Fatigue Overloading Environment

This type of damage may cause issues such as:

• Cracks Delamination
• Scaling
• Spalling
• Abrasions

Concrete Testing can help identify the extent of the damage so that maintenance and repairs can be conducted prior to failure of the asset.

An intrusive investigation directly impacts the area that is tested. For example, Carbonation Measurement requires drilling into the concrete structure to obtain a dust sample for laboratory tests to be conducted. Intrusive methods can be used alongside non-intrusive techniques for comprehensive testing. Non-intrusive investigations inspect and gather information without disturbing the structural asset.

For example, a rebar scanner can observe the depth and size of the reinforcement bars within a concrete asset, without directly impacting the concrete. Non-intrusive methods are considered quicker and more cost-effective, but they cannot offer the same level of in-depth sampling and analysis that intrusive methods provide.

The most common causes of deterioration in concrete are: Overloading and impacts: When concrete structures are subjected to significant loads, they may develop micro-cracks and larger cracks. Such overloading can result from operational changes in the concrete structure that lack appropriate structural upgrades and unusual events like earthquakes. Chemical attack: This can occur when sulfates (of sodium, potassium, calcium, or magnesium) that are dissolved in soil, seawater, or groundwater, permeate the concrete. These compounds react with the hydrated compounds and expand, causing concrete damage. Fire damage: When concrete structures are exposed to high heat, they lose their compressive strength and elasticity. Reinforcement corrosion: This occurs when the concrete’s pH is reduced to 10 or less. The reduction in the pH allows chloride ions, oxygen, and moisture into the pores and micro-cracks. This leads to the rust volume being greater than steel, which stresses the surrounding concrete, resulting in cracks, delamination and spall. Carbonation: This occurs when carbon dioxide penetrates through the pores and micro-cracks of the concrete. The carbon dioxide reacts with the hydroxides, such as calcium hydroxide, which forms calcium carbonate. The product of the reaction reduces the pH in the concrete structure; this exposes the reinforcement bars to corrosion.

Spall is a term used to describe the fragments that fall off or break off a bigger object. Spalling can occur when the concrete structure is exposed to excess moisture, corrosion, and weathering. For example, sometimes small sections of concrete can break off a bridge due to corrosion from excessive wet weather.

Rebar Testing can be an intrusive or non-intrusive method of structural investigation. The intrusive method for rebar testing involves physically exposing the reinforcement bars through drilling or removal of concrete, the asset is then visually inspected or scanned to examine the rebars. The non-intrusive method of rebar scanning involves scanning the surface with scanning equipment, such as a Ferroscan to analyse the distance of the rebar and accurately measure the location and depth of the reinforcement bars.

High Alumina Cement (HAC) is a type of cement that is composed primarily of calcium aluminates. A high amount of alumina cement can cause issues with the concrete structures’ strength and leave it susceptible to chemical damage.

Concrete structures should be inspected regularly to maintain safety standards. The recommendation is to have a routine inspection every five years. Regular concrete testing will ensure the structural integrity of your asset.

Duty holders will typically have a legal obligation to maintain and carry out concrete testing on structures if it has been made part of a contractual agreement. For example, railway companies will often have a contractual obligation to ensure structures are compliant and safe to use.

Depending on where the structure is situated, there may be several external factors which impact access such as weather, heights, water, and remote locations.

We’re proud to provide a variety of Specialist Access Support techniques such as Confined Space Access, Drone Inspections, Rope Access, Suspended Working Platforms and Marine Safety systems to help investigate concrete structures and identify hidden critical elements.