Tarmac Toproc Ready-Mix Concrete - Forth Road Bridge - Edinburgh

The project required concrete with a minimum strength of 60 MPa combined with a high workability and long workability life to strengthen the bridge’s legs and foundation. Toproc AA was specified due to its excellent plastic properties and the material was placed into the legs of the bridge using a combination of boats, trolleys, ships and chutes. The Toproc AA flowed into place easily without any segregation and the precise formulation techniques devised by Topmix’s Special Products staff provided the site with a workability life of 3 hours. Target strengths were substantially exceeded and total performance confidence was provided by specifying Toproc AA.


Whilst its superb hardened characteristics and high strength are its most striking features, Toproc AA is frequently specified for its beneficial properties. Often, when a high strength concrete is specified, there are placement restrictions which requires a mix that must be both highly workable and provide 2 hour workability life on site to enable the concrete to be slowly poured or pumped into position. These somewhat conflicting demands cannot easily be accommodated by conventional concrete. But with Toproc AA, the unique formulation optimising the performance of microsilica, produces a cohesive mix with no segregation or bleeding which also provides the specified high strength.

Mix Used: High Flow Toproc AA ready-mix concrete

Workability: 350mm flow

Beneficial Features: Easy placement, high strength, low shrinkage, high bond

Strength Achieved: 80 MPa in 28 days

This information has been sourced, reviewed and adapted from materials provided by Tarmac Ltd.

For more information on this source, please visit Tarmac Ltd.


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