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HAC Investigations

Investigating the presence and conversion of HAC

Our investigation proposals & approach regarding High Alumina Cement has been adopted by Network Rail and other large civil engineering consultants to ensure a correct diagnosis of the HAC condition is achieved.

HTA utilise various NDT technologies to remove & minimise the risk of causing damage to the structure such as utilising impulse radar to avoid pre-stressing strands and post tensioning systems.

In addition HTA have significant experience using Ultrasonic testing to assist with the assessment of the concrete strengths and any potential weakening caused by HAC conversion.

HTA have been involved with a number of projects investigating the presence and conversion of HAC and its effects on strength. HTA in one instance has been monitoring and testing a structure over a 30 year period.

Understanding HAC to ensure a correct diagnosis

HAC condition investigations with from HTA

HAC concrete can be unaffected by any strength reductions for a number of years.

However changing exposure conditions many years after construction (eg, leaking waterproofing systems) can activate the conversion process and dramatically reduce the strength of the concrete.

High Alumina Cement (HAC) was first used in 1925, and more commonly used in the 50’s, 60’s and 70’s. The HAC concrete gained strength rapidly and meant fast manufacture became possible.

The material was widely used in the construction of precast beams, which were then used to construct buildings and bridges.

In certain instances a crystalline re-arrangement (conversion) to the HAC concrete could take place, which could result in a reduction of concrete strength, and in the most extreme case, failure of element, which could lead to collapse of build / bridges.

Investigate further with HTA

Take advantage of our Open Door Policy

Even if you do not end up using HTA we are happy to advise on the best course of action for the outcome you wish to achieve.

It is impossible for one company to carry out every project, however we can share our expertise far and wide.

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