cement

[b21playa]

Hi all

I bought 20bags if cement a few months ago and stored them indoors.

Now the expiry was feb 2009. The bags are hard but when opened it crumbles.

Is this ok to use for bricklaying?

 

[hotrod]

No, it's gone off

 

[Richard C]

I understand the use by dates are mainly to do with skin irritants in the cement, apparently they get worse with as the cement ages; but if it's started to go hard, damp has got to it & in that case the chemical reaction associated with curing has already begun. Personally I wouldn’t take the chance but, in reality, I don’t know how much difference it makes; as a very famous cop once said, “do ya feel lucky, punk”.

 

[b21playa]

I understand the use by dates are mainly to do with skin irritants in the cement, apparently they get worse with as the cement ages; but if it's started to go hard, damp has got to it & in that case the chemical reaction associated with curing has already begun. Personally I wouldn’t take the chance but, in reality, I don’t know how much difference it makes; as a very famous cop once said, “do ya feel lucky, punk”.

dont know how it got damp., its in the lounge.

i mixed some up yesterday to lay a few bricks ti fit concrete lintel and didnt seem too bad

 

[joe-90]

I think it's the humidity that gets to it. Better stored in the garage on a pallet. Better still to buy it when you need it - no matter how good the deal.

 

[Richard C]

dont know how it got damp., its in the lounge.

Sounds like your lounge is damp then.

i mixed some up yesterday to lay a few bricks ti fit concrete lintel and didnt seem too bad

Well, as I said, do you feel lucky for what the cement costs in comparison to the cost of pulling your project down & starting over again, I certainly wouldn’t risk it But then I only ever buy cement & plaster the day before I'm going to use it

 

[^woody^]

It may feel hard in the bag or if pressed, but if it crumbles easily back to powder, then you can use it.

Strengh wise, it is not a problem, the only issue will be if it remains lumpy, in which case it will be a right pain in mortar as you can't press the bricks down.

Normally, the bits at one or both ends of the bag can be pulled out as a hard lump and discarded if need be, but you can salvage the middle bit

 

[b21playa]

It may feel hard in the bag or if pressed, but if it crumbles easily back to powder, then you can use it.

Strengh wise, it is not a problem, the only issue will be if it remains lumpy, in which case it will be a right pain in mortar as you can't press the bricks down.

Normally, the bits at one or both ends of the bag can be pulled out as a hard lump and discarded if need be, but you can salvage the middle bit

Perfect woody. I will take lumps out and use anything that crumbles down

 

[Richard C]

It may be “perfect” that Woody has given you the answer you were obviously hoping for & really wanted all along but it doesn’t change the facts; you’ve been advised by 3 other contributors it would be ill advised to use it . When cement starts to go hard, the chemical curing action has already begun, it cannot be reversed. The strength & wearing ability of the mortar mix WILL be affected & the surface may be crumbly; whilst it may be suitable for filling fence post holes, I would not advise building a structural wall with it.

But I guess your going to chance it anyway but, remember, you have been warned!

 

[^woody^]

All cement in the paper bags will gradually go hard from the outside in.

Typically, its just the very outer surface which was near the paper bag, and this tends to crumble - it does not mean that the cement has gone off. This is natural with any bags stored for a while

It has only gone off and of no use, if it forms hard clumps of cement. If it is still powdery (albeit a lump of powder), then its usable

If you squeeze a lump and it does not beak apart to powder, then its not usable.

For use in mortar for domestic purposes, then it will be fine. If the OP is worried, then he can throw in another 1/4 shovel per mixer to compensate, but I don't think it will be necessary

The actual setting and hardening of cement is different. The chemical reaction starts as soon as it is made and exposed to the moisture naturally present in the air. The bags prevent rapid escalation of the reaction, but don't stop it. So even in the bag the cement is effectively setting, and until it is one solid mass of cement, then it is still usable as long as it is powdery and can bind the aggregates

AFAIK, the "use by" date relates to the constituents within the cement causing skin dermatitis - a certain date by which the effects are known and after which the effects can affect the skin more - therefore under COSHH regs, the manufacturers are obliged to print a date for H&S purposes. This has nothing to do with the actual usability of the cement.

If its powder, use it.

 

[Richard C]

 

[hotrod]

Woody you cheapskate!

You will be telling him to use a garden sieve next

You can lead a horse to water...................

 

[^woody^]

Save the planet!

BTW, I like the sieve idea - you've done this before haven't you

 

[wavetrain]

Since we are talking about mortar here and not concrete and with mortar, having it too strong is not desirable, I would buy a new bag and do some trial brick to brick mortar joints with old and new at 6:1, leave them damp for a week and test for guessed strength after 2 weeks total time when dried out.

Hardly scientific but more so than many labourers who just guess the amount of cement to chuck in when mixing for the bricky.

Also if the mortar joints are going to be rendered with fresh cement, even less to worry about.


It is the humidty indoors that does this setting in the bag, better to leave outside in an unheated but completely damp free brick outbuilding if stuck with stock to store for a while, or even wrap up in plastic in store?

Are the plastic mastercrete bags any better in this respect woody?

 

[lostplan]

Hello.... I had several Bags cement from jewsons,the mixes were drying to a powder as though id only used sand in the mix. I started using more and more cement to even trying a mix at 2-1. The bags were brand new. One mix was so bad i ditched that bag i was working from and put it outside, in the rain, its still outside now 3 weeks later, and its still POWDER....!! So far ive done a new chimney, rendered a wall, and window reveals that i already had to do twice. Is this Bad cement or am i a moron. Going to Jewsons monday to comlain.