Tricel Novo UK10, Technical Manual

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5.7 Concrete specification
Semi dry concrete 25n grade with a ratio of 4.5 aggregate to 1 cement.
Important:
• Standard concrete mixes should not be used, where sulphates or similarly aggressive
chemicals are present in the groundwater.
• Lift height (rate of rise): Determine the lift height (m), or rate of rise (m/h) for the specific
type of concrete used to ensure that you do not exceed the design pressure (P max) of
15kN/m2 on the tank.
•
Vibration: The tank design assumes minimal compaction of the surrounding concrete.
Where necessary, this may be extended to include internal light vibration. Never use deep
reverberation which will substantially increase the pressure on the tank, possibly causing
failure.
•
Impact of concrete on discharge: Under no circumstances should concrete be discharged
directly onto the tank.
5.8 Topsoil requirements
Clean native top soil shall not contain rocks larger than 36mm in the largest dimension.
Note:
The use of geo textile barrier fabrics surrounding the primary backfill material is considered
good installation practice. The fabric must be chosen to allow the flow of water in and out
of the excavation but to prevent the movement of fine soil particles into the primary
backfill material.