Concrete floor for new grain store

[nt farm]

Hi All.

Putting up a new grain store at the moment and looking at the floor.

Option 1. rc 35 with weld mesh over the whole store and entrance apron and columns tied in to floor with v shape rbar.

option 2. use rc35 with added fibre and just put sheet of weld mesh by each column and column tied in again with v shape rbar.

my main question is are we ok to use fibre in grain store concrete.

Cant find answer in red tractor guides, also called NFU callfirst and they did not know either. any help would be gratefully received.

\cheers

 

[BobGreen]

If you use full structural fibres and the floor is a power floated finish you will have fibres stuck out of floor which I guess will end up in the grain when bucket scrapes along floor so I would use steel mesh. It’s cheaper anyhow

 

[Steevo]

Option 1 for sure!!

 

[dannewhouse]

Use polymer fibres?
I'm sure the micro fibres are the way forwards?

 

[Steevo]

Use polymer fibres?
I'm sure the micro fibres are the way forwards?

No substitute for mesh.

 

[Tractor Tim]

Mesh is far superior to fibres also a rc 35 relates to the amount of cement in the mix so 35 kg of cement per cube which isn't that strong

 

[goodevans]

350 kg so about a 6 to 1 in old terms when we used to chuck it in the belle,mind you there was always more sand and gravel on the shovel than cement though

 

[Case290]

That 35 is for footings yourd be better with s3 40 in the summer 50 in the winter straight Portland cement + fibres 110slump

 

[BobGreen]

Mesh is far superior to fibres also a rc 35 relates to the amount of cement in the mix so 35 kg of cement per cube which isn't that strong

It’s 350kg cement/ cu m

 

[Steevo]

Mesh is far superior to fibres also a rc 35 relates to the amount of cement in the mix so 35 kg of cement per cube which isn't that strong

350 kg so about a 6 to 1 in old terms when we used to chuck it in the belle,mind you there was always more sand and gravel on the shovel than cement though

It’s 350kg cement/ cu m

I was always told it's nothing to do with the amount of cement in the mix.

A C35 is the strength measurement i.e. 35N/mm2 at 28 days.

 

[goodevans]

Interesting as 2 different Google searches gave an answer that was both correct for my assumption and yours @Steevo

 

[nt farm]

Just been on Hansons website looking at there different mix's for grainstore floor. They have section about farm concrete for different uses. What they don't say is how strong the mix is but do say that it does not need mesh in it!!!

 

[nt farm]

The way forward will come done to cost I suppose. Had quote for weld mesh so will get some prices for different grades of concrete and compare.

 

[Steevo]

Just been on Hansons website looking at there different mix's for grainstore floor. They have section about farm concrete for different uses. What they don't say is how strong the mix is but do say that it does not need mesh in it!!!

Annoys me when companies do that - keep the nitty gritty info secret and just try to sell you a "name" on trust that you can't properly compare. Must confuse their staff a bit too I would think.

 

[BobGreen]

Annoys me when companies do that - keep the nitty gritty info secret and just try to sell you a "name" on trust that you can't properly compare. Must confuse their staff a bit too I would think.

That’s because they reduce cement content by using chemical additives so they can reduce the water content but still keep water/cement ratio the same

 

[Steevo]

That’s because they reduce cement content by using chemical additives so they can reduce the water content but still keep water/cement ratio the same

Ah I see, purely to cut cost?

I wonder if volumetric mixer trucks pull the same trick so they aren't carting quite so much water around.

 

[BobGreen]

Ah I see, purely to cut cost?

I wonder if volumetric mixer trucks pull the same trick so they aren't carting quite so much water around.

I don’t know about the volumetric ones. I know they mainly use op cement not a blend but the water addition is a bit hit and miss

A local independent firm I know puts 350kg in a cube whereas a national one has less than 300kg in the same mix by reducing the water by use of additives. That is why if you add water onsite you have to sign for it as if the concrete fails you have no comeback as basically you’ve turned a c35 into a c20/25
That is why it’s best to specify a minimum cement content with a specific water/cement ratio

 

[solo]

I was always told it's nothing to do with the amount of cement in the mix.

Interesting as 2 different Google searches gave an answer that was both correct for my assumption and yours @Steevo

A C35 is the strength measurement i.e. 35N/mm2 at 28 days.

I had some tenants who worked for Ready Mix some years ago. One of their jobs was to attend sites to take 8cm cubic samples of the concrete being laid. Once dried these were then put in a press which gave the NM pressure at which the sample crumbled. These results would be kept in case of any disputes.
I guess you could make your own device using a torque wrench.

 

[Forever Fendt]

I was always told it's nothing to do with the amount of cement in the mix.

A C35 is the strength measurement i.e. 35N/mm2 at 28 days.

correct the figure given is nothing to do with the amount of cement its the compressive strength achieved at 28 days there are many ways achieving this with varying amounts cements

 

[Forever Fendt]

I don’t know about the volumetric ones. I know they mainly use op cement not a blend but the water addition is a bit hit and miss

A local independent firm I know puts 350kg in a cube whereas a national one has less than 300kg in the same mix by reducing the water by use of additives. That is why if you add water onsite you have to sign for it as if the concrete fails you have no comeback as basically you’ve turned a c35 into a c20/25
That is why it’s best to specify a minimum cement content with a specific water/cement ratio

Exactly how we see it