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Concrete Testing

Concrete Condition Surveys

OnSite Specialist Maintenance Limited carry out all types of concrete sealant applications. We are an approved concrete sealant company for many concrete sealant manufacturers.

What are Concrete Condition Surveys?

Reinforced concrete itself is a complex composite material. It has low strength when loaded in tension, hence it is common practice to reinforce concrete with steel for improved tensile mechanical properties. Concrete structures such as bridges, buildings, elevated highways, tunnels, parking garages, offshore oil platforms, piers and dam walls all contain reinforced steel (rebar). The principal cause of degradation of steel reinforced structures is corrosion damage to the rebar embedded in the concrete.

The two most common causes of reinforcement corrosion are:

  • 1. Localised breakdown of the passive film on the steel by chloride ions
  • 2. General breakdown of passivity by neutralisation of the concrete, predominantly by reaction with atmospheric carbon dioxide, commonly known as CARBONATION.

Sound concrete is an ideal environment for steel but the increased use of de-icing salts and the concentration of carbon dioxide in modern environments due to industrial pollution has resulted in corrosion of the rebar.

Onsite Specialist Maintenance Ltd carry out full or part concrete condition surveys in order to determine the corrosion rate. Our documents and accompanying remedial specifications are often used by our clients to form tender documents for any remedial works required following our survey.

Concrete Testing:

  • Carbonation depth testing
  • Acoustic sounding survey
  • Cover-metre survey
  • Chloride analysis
  • Half cell potential
  • Petrographic analysis
  • Sulphate content
  • HAC content
  • Cement content

Contact us online now or call us on 0115 933 5010

Recent Concrete Testing Project -

Network Rail Over Bridge, Norwich


Acting on behalf of Pick Everard Leicester, Onsite Specialist Maintenance Ltd was awarded the contract to undertake a concrete condition survey on behalf of National Grid. The bridge which forms the main access to the local National Grid Depot spans the Network Rail lines. The bridge was showing signs of deterioration and the survey was undertaken to identify all defects and the causes of deterioration.

Concrete repair solution:

Utilising OnSite Specialist Maintenance’ direct employed PTS trained operatives we carried out a full acoustic hammer survey of all concrete elements, numerous carbonation depth tests, chloride samples, cover metre survey, half cell potential survey and petrographic analysis of two concrete cores as Alkali Silica Reaction was a concern in one column. The report allowed the structural engineers Pick Everard to make a calculated assessment of the structure and the repair specification and budget costings provided proved useful to both engineer and client for planning their repair strategy.

The level of information provided was excellent which in turn made our job easier. OnSite Specialist Maintenance direct employed staff and especially the PTS trained operatives made working alongside a live railway a little less daunting.

David Lennon
Pick Everard
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