What effect would too much or too little plasticiser have on mortar?

isnottheword

Quick query....


If too much or too little plasticiser was used in a mortar mix on a blockwork wall, what are the effects of same?

i.e. would it mean that the strength of the mortar would be compromised? Is this something that can be easily tested for in a lab? (i.e. they could provide a definitive answer)?


I assume there's a reason why a blocklayer would use too much or too little? Does either case make life easier for him?

What would be the effect of substituting plasticiser with fairy liquid or the likes?

dfader

isnottheword wrote: »

Quick query....


If too much or too little plasticiser was used in a mortar mix on a blockwork wall, what are the effects of same?

i.e. would it mean that the strength of the mortar would be compromised? Is this something that can be easily tested for in a lab? (i.e. they could provide a definitive answer)?


I assume there's a reason why a blocklayer would use too much or too little? Does either case make life easier for him?

What would be the effect of substituting plasticiser with fairy liquid or the likes?

Plasticiser is whats called an admixture designed to impart certain properties to the hardened mortar such as watertightness, flexibility. Fairy liquid is designed to make dishes nice and clean and your hands soft.
Some plasterers or blockies might like to use it as in makes the wet mix more workable, but its terrible practice and if it were my house they d be ran. Will result in a brittle mortar that will crack and let in water or renders that will crack and even fall off. Too much or to little dosage not good either, its designed for certain dosage.

SC024

Fairy Liquid is a big no no over time it degrades the mortar & makes it go soft.

isnottheword

Thanks both.

So if such mortar was tested in a lab - say 8 years later, would it not have the same compressive strength as per whatever the normal parameters are for that?

dfader wrote:

Fairy liquid is designed to make dishes nice and clean and your hands soft.

I'm all for blocklayers having soft hands if that's that they're into - but not at the expense of seriously defective workmanship.:D

Are we also in agreement that too much plasticiser would have major implications?

How bad could the outcome be in either of those scenarios?

Is there a guideline/standard for same or is it vague? i.e. just indicates recommended mortar mix ratio?

Calahonda52

isnottheword wrote: »

Thanks both.

So if such mortar was tested in a lab - say 8 years later, would it not have the same compressive strength as per whatever the normal parameters are for that?

I'm all for blocklayers having soft hands if that's that they're into - but not at the expense of seriously defective workmanship.:D

Are we also in agreement that too much plasticiser would have major implications?

How bad could the outcome be in either of those scenarios?

Is there a guideline/standard for same or is it vague? i.e. just indicates recommended mortar mix ratio?

As to quantity, it is set out very clearly on the container

The problem with these questions is they are too vague.
IIRC this approach is one you have used before, so rather than sase the reason for your questions, you start this wide-ranging what if line of ....:D:D:D:D

isnottheword

@Calahonda52: I'm not sure how I can put it any clearer. The question is what effect would too much or too little plasticiser have on mortar?

Anyway, from what I've learnt in the meantime, it seems that too much would lead to a weakening of the mortar.


I'm in the process of getting tests done on a core sample. Now, I could ask what are the norms one would expect in terms of compressive strength of mortar i.e. is there a range set out somewhere ...in building regs, etc. ?

Can you extend me the courtesy of being able to pose that question without the commentary? If you don't know the answer or don't want to answer, that's entirely fine. At the end of the day, we all use message boards to exchange information...something that cuts both ways depending upon the subject area/topic/query.

Metric Tensor

Assuming a "old fashioned" 5N block you would expect the mortar to be 4N.

If you can lay your hands on the old BS 5628 masonry standard there's some good reading in it. It's not current anymore (Eurocode 5 is in place) but it's better reading for the lay person and indeed non lay people too. It's less "codified". There was a companion document and an Irish document too whose numbers escape me now. If I get a chance tomorrow I'll find their names.

Metric Tensor

Additional references:

PD 6678
PD 6697
SR 325

There have been various updates and superseding activity since the introduction of Eurocode 6 so some/all of the above may have multiple versions and may also be in or out of date. Regardless - if background reading and an understanding of how these things are specified is what you are after all of the above will be of help.

isnottheword

Thanks MT. Will check those out.