Vagueness and the Aftermath - A sporadic diary

[RED-DOG]

Why is concrete stronger than mortar when, barring a few pebbles, it's the same thing?

Imagine sticking a couple of reinforcing a 6in square strip of mortar and using it to replace a concrete fence post....

[RED-DOG]

As for my play, as a famous scribe so eloquently writes, that's for another day...

Eloquent Schmeloquent. Was he having an off day?

[tikay]

Why is concrete stronger than mortar when, barring a few pebbles, it's the same thing?

Imagine sticking a couple of reinforcing a 6in square strip of mortar and using it to replace a concrete fence post....

Mortar does not contain aggregate, Tom. ("Aggregate" is rather different to "a few pebbles").

Mortar is SOFT sand (to bind it), cement, & water. It needs to be LESS strong than the bricks, so that it can "give". If you see a fractured piece of brickwork, the fracture invariably starts with the mortar.

Concrete contains, usually, SHARP sand, & aggregate, both being crucial. The difference between so-called" soft" sand & "sharp" sand is immense. You can feel it, too, soft sand feels powdery, sharp sand is exactly that, sharp, with a very gritty feel. That "grit", & the aggregate, are the components which, along with the OPC, create concrete, & give it strength. That strength is compressive ONLY, not tensile. Compressive & tensile strength are completely different. Unreinforced concrete has almost no tensile strength - reinforcement bars, or mesh, are required to be included for tensile strength.

I cannot begin to imagine anyone who would be dumb enough to try to construct a fence post out of mortar.

[tikay]

As for my play, as a famous scribe so eloquently writes, that's for another day...

Eloquent Schmeloquent. Was he having an off day?

It's a euphemism Tom. It means "not for discussion, so you can piss right off".

[RED-DOG]

Why is concrete stronger than mortar when, barring a few pebbles, it's the same thing?

Imagine sticking a couple of reinforcing a 6in square strip of mortar and using it to replace a concrete fence post....

Mortar does not contain aggregate, Tom. ("Aggregate" is rather different to "a few pebbles").

Mortar is SOFT sand (to bind it), cement, & water. It needs to be LESS strong than the bricks, so that it can "give". If you see a fractured piece of brickwork, the fracture invariably starts with the mortar.

Concrete contains, usually, SHARP sand, & aggregate, both being crucial. The difference between so-called" soft" sand & "sharp" sand is immense. You can feel it, too, soft sand feels powdery, sharp sand is exactly that, sharp, with a very gritty feel. That "grit", & the aggregate, are the components which, along with the OPC, create concrete, & give it strength. That strength is compressive ONLY, not tensile. Compressive & tensile strength are completely different. Unreinforced concrete has almost no tensile strength - reinforcement bars, or mesh, are required to be included for tensile strength.

I cannot begin to imagine anyone who would be dumb enough to try to construct a fence post out of mortar.

I know the difference between sharp sand and soft, or 'builders' sand, as we call it in the trade.

The difference is, sharp sand is composed of bigger pebbles.                

[tikay]

Why is concrete stronger than mortar when, barring a few pebbles, it's the same thing?

Imagine sticking a couple of reinforcing a 6in square strip of mortar and using it to replace a concrete fence post....

Mortar does not contain aggregate, Tom. ("Aggregate" is rather different to "a few pebbles").

Mortar is SOFT sand (to bind it), cement, & water. It needs to be LESS strong than the bricks, so that it can "give". If you see a fractured piece of brickwork, the fracture invariably starts with the mortar.

Concrete contains, usually, SHARP sand, & aggregate, both being crucial. The difference between so-called" soft" sand & "sharp" sand is immense. You can feel it, too, soft sand feels powdery, sharp sand is exactly that, sharp, with a very gritty feel. That "grit", & the aggregate, are the components which, along with the OPC, create concrete, & give it strength. That strength is compressive ONLY, not tensile. Compressive & tensile strength are completely different. Unreinforced concrete has almost no tensile strength - reinforcement bars, or mesh, are required to be included for tensile strength.

I cannot begin to imagine anyone who would be dumb enough to try to construct a fence post out of mortar.

I know the difference between sharp sand and soft, or 'builders' sand, as we call it in the trade.

The difference is, sharp sand is composed of bigger pebbles.                

Yes, for reasons which I'm unclear, soft sand is generically known as "builders sand", which is a bit odd rerally.

Stop keep calling sand "pebbles", you are just trying to wind me up, whilst at the same time showing your ignorance.


SAND DOES NOT CONTAIN PEBBLES.

Do I make myself clear?

Pebbles are exactly that, pebbles. Little lumps of rock, or stone, round or oval but predominantly smooth, completely absent of the smaller granules which are in aggregate.

Aggregate can contain pebbles, pebbles cannot contain aggregate. Sand cannot contain pebbles. Pebbles cannot contain sand.

Pebbles. Sand granules. Different things.

We don't WANT pebbles in aggregate really, as pebbles are round, & don't add much strength. We need sharp bits, of varying sizes & angularity, to give strength.    



PEBBLE

Click to see full-size image.

SAND

[tikay]

Look, NO PEBBLES.

[Tal]

Cementitious

We'll see if we can slip that into a post today...

[tikay]

Cementitious

We'll see if we can slip that into a post today...

If Tom's not careful I'll slip a pebble right up his arse.

[theprawnidentity]

Concrete thread delivers

[RED-DOG]

Sand is just a lot of little tiny pebbles. Fact.

[tikay]

Sand is just a lot of little tiny pebbles. Fact.

Wrong.

By definition, a pebble has a minimum particle size of 2 millimetres. The maximum pebble size is 64 millimetres, larger than that is a cobble.

Sand consists of granules, which, by definition, are smaller.

Fact.

[tikay]

And pebbles are round, or oval, whereas sand is angular.

Be told.

[RED-DOG]

Close-up (1×1 cm) of sand from the Gobi Desert, Mongolia.




I suggest you try the duck test.

[tikay]

Stop digging Tom.

Just accept you were wrong, apologise unreservedly, bow to my superior whatsit, and I'll call it a draw.

Can't be fairer than that.

Off for a kip now, might poodle up to DTD for the £30 thing tonight, you going?