Cement 'Shelf-life' Expired - Still OK To Use Though?

[Tozzy]

Hi there,

Just a quick question. I've had a bag of unopened portland cement for a good couple of months after the expiry date. I really need this for an urgent pointing job so I could really do with knowing asap if it's still ok to use.

It says something about the reducing agents becoming ineffective after this date so they won't be able to react with water as before.

Please could someone clear this up for me. I've tried searching, but didn't find any results related to my query. Also, not much on the web to give me a direct answer .

Would really appreciate.

Thank you.

 

[JohnD]

I remember from a Concrete Association guide: "if the cement is free of lumps that cannot easily be broken up in the fingers" it is OK to use.

Of course this was not for any of the calculated strength mixes, just for common raft and garden work.

So if you are using it for a garden path, or non-structural pointing, not a column or a foundation, and it hasn't gone hard from damp, it should be OK. I would take care to keep it damp while it cures to maximise your chances of success.

If it is for anything important, splash out a few quid on some new.

 

[Tozzy]

Thanks very much your quick reply JohnD. I can now start my work today so I'm very grateful for your help. Sorry my post is a bit late, but I had connection problems last night.

Thanks again.

If it is for anything important, splash out a few quid on some new.

Nah, it's just for the outside pointing on a wall . Wall is already there, but mortar has cracked. Doesn't have to be really strong.

 

[RigidRaider]

Just don't use it for building.... I've seen a few collapsed houses in Nigeria that were made from gone off cement that had sat for months in ships outside the port.

All the squatters living inside were killed.

 

[masona]

Just a quick question. I've had a bag of unopened portland cement for a good couple of months after the expiry date. I really need this for an urgent pointing job so I could really do with knowing asap if it's still ok to use.

It's recommended to use lime when repointing, see here to help you.

 

[Tozzy]

Just don't use it for building.... I've seen a few collapsed houses in Nigeria that were made from gone off cement that had sat for months in ships outside the port.

Damn!! In that case, it looks like I'd better pull the house down before it falls down ....

just kidding there mate . Nah, it was just to repoint some bricks where the mortar had cracked; it was very badly cracked actually .

It's recommended to use lime when repointing, see here to help you.

Thanks for the tip masona . Unfortunately the work has already been done, but nevertheless, I will refer to this link in the future.

Cheers for your replies guys.

By the way:

Use sharp sand with lime, and soft sand with cement.

Until now, I didn't know you could use both lime and cement together.

So if I use the ratio, 6:1:1 mix of sand/lime/cement, do I use sharp sand or soft sand?

Thanks in advance.

 

[masona]

Soft sand for repointing, unless it's really deep.

 

[Tozzy]

Soft sand for repointing, unless it's really deep.

It's recommended to use lime when repointing.

Use sharp sand with lime,

So if I use lime, I don't use soft sand. You mean use soft sand with cement? But you was the one that suggested using lime and it says above to use sharp sand with lime. But, if use lime and cement together at the same time, do i use soft sand or sharp sand? Does it matter what grade of sand is used if you're using both lime and cement?

Sorry if I'm confusing you.

Oh and the consistency, is it supposed to be like runny paste or soft where it doesn't stick to your fingers? I have a bad feeling that I've not added enough water . It seems like I can scrape the sand off with my fingers . I thought it was a good mix though because I used 3:1 soft sand and cement and managed to roll the whole thing into a pattie ball .

 

[masona]

If the pointing is less 12mm then use soft sand/lime/cement 6:1:1 ratio, if it's more than 12mm deep then best to use sharp sand instead of soft sand as it will help for strength.

The idea of using lime is to make it soft & more flexible rather than hard and rigid, the cement on it own without lime will cracks eventfully

 

[Tozzy]

Cheers Masona!

That's very helpful. I understand now . Problem is though, the gaps were deeper than 12mm and I used soft sand lol . Ah well, I'd never done repointing before so I will know for next time .

Thanks again .