If I want to achieve a reasonably good flow rate with home-mixed concrete, so that it flows down into some narrow crevices easily. I seem to have two options:
a) Use a litre or so more water per mixer load, to make the mix more runny. or b) Use a relatively tiny amount of plasticiser to make the mix more runny.
I'm finding conflicting advice on the pros vs cons of using plasticiser in concrete. On one hand, some say it increases the strength of concrete becau se it enables the use of less water. Others say that plasticiser reduces th e strength of concrete!
I bought a bottle of Bostic mortar plasticiser, but was dismayed to read in the small print that it should not be used in "load-bearing" concrete! (I thought almost all concrete ends up being load-bearing!) Although, in my ca se, it's not going to be bearing much load - only a course or two of 9" x 9 " x 18" concrete blocks
One of you suggested that plasticised should be avoided because it inhibits water from leeching to the surface during the settling process. But couldn 't this simply be because less water is present in the mix?
Any insights or clarifications on this? I googled it, and found very little evidence to convince me one way or the other. Most of the information onli ne seems to be from companies selling plasticiser and is therefore possibly biased. I was hoping to find some actual test results.
It's not really a life-or-death situation, in my case - I'm just interested in knowing the truth!
Thank you!
Al