I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard

On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Angular aggregates are quarried and are uniform hence stronger because they are purposed for concrete..

So the strength of the concrete is not because of the shape of the aggregate but in the strength of the aggregate.

If you look at broken concrete, the break line is always through the aggregate. The supplier should be able to tell you the mix that will give maximum strength. Which depends on the strength of the aggregate.
Putting more cement in that this serves no purpose.

Tricky Dicky Wrote in message:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


How much of a vehicle potentially?
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Jim K


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harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

How much of a vehicle potentially?

An SUV, it is only a small section to connect the original concrete hard standing to the new garage base. Flat at one end and tapering at a slight angle at the other with a width of approx. 400mm. I will be mixing it my self, I think I calculated it at approx. 0.1m3.

Richard

Tricky Dicky Wrote in message:

How much of a vehicle potentially?

An SUV, it is only a small section to connect the original concrete hard standing to the new garage base. Flat at one end and tapering at a slight angle at the other with a width of approx. 400mm. I will be mixing it my self, I think I calculated it at approx. 0.1m3.

Richard


If you've got ballast just use that but don't skimp on the cement
- you don't want to do it twice!
If buying in, I'm 100% sure bags of Wickes eg pebbly aggregate &
sand will be more than fine & upto the job.

0.1m3 ? 100litres?
--
--
Jim K


----Android NewsGroup Reader----
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There is also the point that the preparation and thickness are crucial as
concrete is strong in compression but weak in tension.
Thus any voids that might happen over time under the concrete are going to
enable cracks. Tree roots and draining water etc.
Brian

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This newsgroup posting comes to you directly from...
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Note this Signature is meaningless.!
"harry" wrote in message
...
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support
some edgings and noted that the coarse aggregate/gravel tended to be
rounded and smooth. I am about to lay a more critical section over which a
vehicle will pass, I have always understood that angular gravel is best
because it tends to "lock" together. Which should I use? I have consulted
the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate
strength runs out.

Pebble types of aggregate all originally came from glacier action and are
recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in
the mix.

Angular aggregates are quarried and are uniform hence stronger because they
are purposed for concrete..

So the strength of the concrete is not because of the shape of the aggregate
but in the strength of the aggregate.

If you look at broken concrete, the break line is always through the
aggregate. The supplier should be able to tell you the mix that will give
maximum strength. Which depends on the strength of the aggregate.
Putting more cement in that this serves no purpose.

On Thursday, 6 September 2018 08:20:35 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

The best way to buy it is as "X" mm down to dust.
This should give the best mix/range of aggregate sizes for maximum strength..
Only cement need then be added.

It's important not to have too much water in the mix and to ensure no air bubbles. Vibrator or well paddled with a shovel.

Also don't do the work in very hot weather and keep it wetted down for around a week. Ideally cover with plastic sheet to keep damp.

harry Wrote in message:
On Thursday, 6 September 2018 08:20:35 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

The best way to buy it is as "X" mm down to dust.
This should give the best mix/range of aggregate sizes for maximum strength.
Only cement need then be added.

I don't recall that being a recommended method? Who controls the
proportions of X and all sizes to dust?
You want enough sand & cement mixture to fill gaps between larger
aggregate, not sure I'd trust some random mixture of crushed old
****e to have the proportions right. X to dust is usually used as
sub base under concrete slabs etc as it compacts
well...

It's important not to have too much water in the mix

Equal amounts of water & cement maximum.
Less water is better (stronger set) but harder to handle & finish
- Google plasticisers but for 0.1m3 I don't think it's worth
arsing about too much.

and to ensure no air bubbles. Vibrator or well paddled with a shovel.

In practical diy terms "well tamped" with a bit of 4x2 should
amply suffice the OPs needs...

--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Thursday, 6 September 2018 17:03:57 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:20:35 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

The best way to buy it is as "X" mm down to dust.
This should give the best mix/range of aggregate sizes for maximum strength.
Only cement need then be added.

I don't recall that being a recommended method? Who controls the
proportions of X and all sizes to dust?
You want enough sand & cement mixture to fill gaps between larger
aggregate, not sure I'd trust some random mixture of crushed old
****e to have the proportions right. X to dust is usually used as
sub base under concrete slabs etc as it compacts
well...

It's important not to have too much water in the mix

Equal amounts of water & cement maximum.
Less water is better (stronger set) but harder to handle & finish
- Google plasticisers but for 0.1m3 I don't think it's worth
arsing about too much.

and to ensure no air bubbles. Vibrator or well paddled with a shovel.

In practical diy terms "well tamped" with a bit of 4x2 should
amply suffice the OPs needs...


It's not a random mix. It's supposed to be carefully graded.
Only cement needed.

"Tamping" it is not good.
It brings the fine aggregate and cement to the surface so weakening the bulk concrete underneath.

On Thursday, 6 September 2018 19:18:30 UTC+1, harry wrote:
On Thursday, 6 September 2018 17:03:57 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:20:35 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

The best way to buy it is as "X" mm down to dust.
This should give the best mix/range of aggregate sizes for maximum strength.
Only cement need then be added.

I don't recall that being a recommended method? Who controls the
proportions of X and all sizes to dust?
You want enough sand & cement mixture to fill gaps between larger
aggregate, not sure I'd trust some random mixture of crushed old
****e to have the proportions right. X to dust is usually used as
sub base under concrete slabs etc as it compacts
well...

It's important not to have too much water in the mix

Equal amounts of water & cement maximum.
Less water is better (stronger set) but harder to handle & finish
- Google plasticisers but for 0.1m3 I don't think it's worth
arsing about too much.

and to ensure no air bubbles. Vibrator or well paddled with a shovel.

In practical diy terms "well tamped" with a bit of 4x2 should
amply suffice the OPs needs...


It's not a random mix. It's supposed to be carefully graded.
Only cement needed.

"Tamping" it is not good.
It brings the fine aggregate and cement to the surface so weakening the bulk concrete underneath.

The size of the aggregate depends on the thickness of the concrete.
It should be no more than one tenth of the concrete thickness.
So 100mm thick concrete needs 10mm aggregate down to dust.

harry Wrote in message:
On Thursday, 6 September 2018 17:03:57 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:20:35 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

The best way to buy it is as "X" mm down to dust.
This should give the best mix/range of aggregate sizes for maximum strength.
Only cement need then be added.

I don't recall that being a recommended method? Who controls the
proportions of X and all sizes to dust?
You want enough sand & cement mixture to fill gaps between larger
aggregate, not sure I'd trust some random mixture of crushed old
****e to have the proportions right. X to dust is usually used as
sub base under concrete slabs etc as it compacts
well...

It's important not to have too much water in the mix

Equal amounts of water & cement maximum.
Less water is better (stronger set) but harder to handle & finish
- Google plasticisers but for 0.1m3 I don't think it's worth
arsing about too much.

and to ensure no air bubbles. Vibrator or well paddled with a shovel.

In practical diy terms "well tamped" with a bit of 4x2 should
amply suffice the OPs needs...


It's not a random mix. It's supposed to be carefully graded

Says who? Reference/link please?


"Tamping" it is not good.
It brings the fine aggregate and cement to the surface so weakening the bulk concrete underneath.


It's worked for generations!

Your recommended "banging it with the back of a shovel" is
somehow superior?!
Bollix
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

harry Wrote in message:
On Thursday, 6 September 2018 19:18:30 UTC+1, harry wrote:
On Thursday, 6 September 2018 17:03:57 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:20:35 UTC+1, JimK wrote:
harry Wrote in message:
On Thursday, 6 September 2018 08:00:27 UTC+1, Tricky Dicky wrote:
I have been using ballast recently for none critical concrete to support some edgings and noted that the coarse aggregate/gravel tended to be rounded and smooth. I am about to lay a more critical section over which a vehicle will pass, I have always understood that angular gravel is best because it tends to "lock" together. Which should I use? I have consulted the Paving Expert but cannot seem to find an answer.

Richard


The strength of concrete depends on the aggregate.
More cement makes it stronger but only up to a point where the aggregate strength runs out.

Pebble types of aggregate all originally came from glacier action and are recovered from the sea and from "gravel pits"
They are always mixed stones and hence weaker because of weaker pebbles in the mix.

Those bags of pebbly aggregate in Wickes for eg don't look like
mixed stones to me....
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

The best way to buy it is as "X" mm down to dust.
This should give the best mix/range of aggregate sizes for maximum strength.
Only cement need then be added.

I don't recall that being a recommended method? Who controls the
proportions of X and all sizes to dust?
You want enough sand & cement mixture to fill gaps between larger
aggregate, not sure I'd trust some random mixture of crushed old
****e to have the proportions right. X to dust is usually used as
sub base under concrete slabs etc as it compacts
well...

It's important not to have too much water in the mix

Equal amounts of water & cement maximum.
Less water is better (stronger set) but harder to handle & finish
- Google plasticisers but for 0.1m3 I don't think it's worth
arsing about too much.

and to ensure no air bubbles. Vibrator or well paddled with a shovel.

In practical diy terms "well tamped" with a bit of 4x2 should
amply suffice the OPs needs...


It's not a random mix. It's supposed to be carefully graded.
Only cement needed.

"Tamping" it is not good.
It brings the fine aggregate and cement to the surface so weakening the bulk concrete underneath.

The size of the aggregate depends on the thickness of the concrete.
It should be no more than one tenth of the concrete thickness.
So 100mm thick concrete needs 10mm aggregate down to dust.


?
Reference /link?

--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Just to clarify a few details the old drive and hardstanding had been there since 1975 with no evidence of cracking or movement. It was 150mm thick on limestone hardcore. The new garage base was excavated to the clay until it presented a scraped finish, crushed limestone varying from about 50mm to fine grains was applied with a minimum depth of 150mm followed with a blinding layer and a DPM and a depth of concrete of 150mm.

The intention is to simply fill the gap between the old and new to the same depth. I have used up all the bulk bags of ballast on the edgings and since I already have sufficient cement and grit sand for the job it is only the coarse aggregate I need to get in. Paving Expert does not have a high opinion of ballast rating it only suitable for none critical work such as I have done so far. Hence my concern on which type of coarse aggregate to use as all the ballasts I have seen contain smooth gravel and a considerable spread of aggregate size to boot.

Not wishing to get into an argument I thought tamping was the way to go in order to bring finer particles to the surface for floating smooth, I stand to be corrected.

Richard

Tricky Dicky Wrote in message:
Just to clarify a few details the old drive and hardstanding had been there since 1975 with no evidence of cracking or movement. It was 150mm thick on limestone hardcore. The new garage base was excavated to the clay until it presented a scraped finish, crushed limestone varying from about 50mm to fine grains was applied with a minimum depth of 150mm followed with a blinding layer and a DPM and a depth of concrete of 150mm.

The intention is to simply fill the gap between the old and new to the same depth. I have used up all the bulk bags of ballast on the edgings and since I already have sufficient cement and grit sand for the job it is only the coarse aggregate I need to get in. Paving Expert does not have a high opinion of ballast rating it only suitable for none critical work such as I have done so far. Hence my concern on which type of coarse aggregate to use as all the ballasts I have seen contain smooth gravel and a considerable spread of aggregate size to boot.

20mm gravel from a shed will do fine. You're not building a
reactor containment building :-)


Not wishing to get into an argument I thought tamping was the way to go in order to bring finer particles to the surface for floating smooth

How do you propose to move the concrete around & into the correct
shape & finish for your requirements?

Maybe Google "tamping concrete"...
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Thursday, 6 September 2018 19:18:30 UTC+1, harry wrote:

"Tamping" it is not good.
It brings the fine aggregate and cement to the surface so weakening the bulk concrete underneath.

1. Every method of getting a smooth level finish does this, except compression of dryish mixes. Vibration does it more so than tamping.
2. You need a bit of extra fine stuff at the top otherwise you get a very lumpy finish!


NT