Other Information
How to place concrete
How to fill ICF walls
Curing concrete
Fixing leaks and sealing joints
What too much water does to concrete
Capillary action in concrete
Settlement cracking
Drying cracking
Thermal cracking
Other bad things that happen to concrete
About OPC
About PFA
About GGBS
About silica fume
About interground limestone
Which is stronger, pure OPC or a blend?
Mixing waterproof concrete by hand
Steel fibres in waterproof concrete
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Why Pay For Supervision?
Because the problems listed below are not covered by anyone's guarantee.
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Not any concrete supplier,
Not any additive supplier.
Not any latent defects insurer.
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That means these problems would
- cost someone money
- delay the programme and the finish date of your project
- lead to failure and repair sooner than desired.
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Remember / bear in mind. As soon as someone uses any concrete from a truck, even the tiniest amount, you have accepted that load.
- Incorrect concrete ordered
- Concrete arrives all at once
- Concrete arrives before the pump is ready
- Concrete arrives, it is wrong, no one checks
- Concrete is too dry to pump
- Unauthorised water added to truck
- Vibrating poker fails to start
- Vibrating poker fails during use
- Big delay between truck loads, dry joint through work
- Additive not mixed thoroughly through an 8m³ load
- Workforce linger with poker in one place
- Workforce move poker more than 200mm each time
- Workforce misses whole areas with the poker
- Poker too weak to be effective
- Hydrophylic strip swells too early
- Hydrophylic strip not fixed down properly
- Water bar not joined up properly
- The wall is not blown clean before concrete goes in
- No tremmie pipe to deliver concrete through wall formwork to within 1250mm of the bottom
- Formwork bursts, concrete is out of time before it is back in the wall
- Poker too 'curly' or too short to get to the bottom of wall formwork
- Bolshi pump operator / operator always on his phone
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- by someone at the supplier who does not understand any more than the person who confirms the order
- insufficient time to place or compact it properly
- the concrete may be out of time before it can be used properly
- the concrete will leak
- the truck driver, the pump operator and the workforce will all want to add unauthorised water
- the concrete will leak over a wide area and resin injection will be needed
- the concrete will leak/not be strong enough
- the concrete will leak/not be strong enough
- danger of leaking till repaired/not be strong enough
- Very common. The first concrete will be too workable and segregate while the last concrete will block the pump and fail to compact
- The concrete will segregate as the stones are knocked away and replaced by grout
- Air left in the concrete in columns between pokered spots
- Simple repairs too expensive. Resin injection required.
- Dig it all out; replace the steel; pour a second time
- Joint leaks
- Joint leaks
- Joint leaks
- The joint leaks, structural weakness
- Stones at the bottom for the first few centimetres; any tape or strip fails, leaks
- All sorts of trouble
- Leaks; needs resin injection
- Mess; danger; broken formwork; even death of a worker
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This list will not be exhaustive.
For instance it does not cover if the concreting gang is too small to do the work properly.
So if you don't have the work supervised, how can you not have leaks?
There is a lot to supervise.
Any guarantee you appear to be paying for is most likely to be worthless because the concrete mix design and the chemicals are foolproof. They are concrete that self-heals to make itself watertight to the point where the chemicals make it fully waterproof. If there is a failure it will be a failure of workmanship.
So the reality is, if your project succeeds, it is despite these people and not because of them.
If you pay me to train and supervise them their work that day will be much better - and who knows, they may develop good practices and supervise themselves in future.
Like so many increases in quality it is hard to quantify precisely the value gained or the savings made. But in all probability your concreting team will be starting from a low base, so making up the £200 I generally cost for a day (including hiring you vibrating pokers that work) is very likely.
Indeed, it is beyond belief, really, that my £200 will not save you more than that somehow.
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A day of supervision is defined as your induction, tool box talk with the gang and supervision of concrete pours or joint treatment for a maximum of 8 hours from start to finish with you and including a 30 minute break off site.
I will try to be flexible, for instance if concrete ordered for 11am does not start to arrive until 2pm. But the 8 hours of work including a 30 minute break still applies else there will be a further charge.
disclaimer and copyright
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