Concrete Information

[asudavew]

Just wanted to post an article that I found helpful.

Chapter 6 Concrete

[Frances]

I put this question elsewhere, but I'll repeat it here, because I really would like an answer:

I've got a book on making concrete sculptures, and it mentions that if you add a squirt of washing-up liquid to the cement you can use less water and so get stronger concrete. This is because washing-up liquid reduces the surface tension of the water. I have tried it and it works, so it would seem like a really good idea, yes?

But I never saw this trick mentioned anywhere else (not in Dave's interesting article either), so I'm thinking maybe it has a bad effects as well. Can anyone help??

Thanks,
Frances

[asudavew]

I've heard that before too.

And if it helps........ I don't think it would hurt anything.

[asudavew]

Sugar Mountain Farm: Float My Concrete Boat

This guy uses dish soap as a surfactant and he claims his insulating concrete floats!

[Unofornaio]

Originally Posted by Frances

I put this question elsewhere, but I'll repeat it here, because I really would like an answer:

I've got a book on making concrete sculptures, and it mentions that if you add a squirt of washing-up liquid to the cement you can use less water and so get stronger concrete. This is because washing-up liquid reduces the surface tension of the water. I have tried it and it works, so it would seem like a really good idea, yes?

But I never saw this trick mentioned anywhere else (not in Dave's interesting article either), so I'm thinking maybe it has a bad effects as well. Can anyone help??

Thanks,
Frances

Adding soap to cement in quantities mentioned in most references to this certainly will not hurt the mix. However I don't believe it makes it stronger. This is a common practice in the UK from what I gather but Ive seen mostly mention of the addition in mortar. It will add some workability to the mix but in my opinion its really not necessary. People do things different around the world so perhaps some of the UK members can shed some light on this practice.

Some grass roots groups in this country have been toying with the addition of adding dishwasher or laundry detergent to concrete to serve as air entrainment additive but again I really have not seen any valuable changes in end product. The theory is that the detergent will add bubbles to the concrete making it less susceptible to cracking because the holes take up expansion in the slab. This does work in ready mix and has been proven over years. The additive in ready mix is a foaming agent but its not quite the same.

Concrete in its simplest form cement, gravel, sand is more than strong enough for any application that doesn't require special engineering. If you make your mix in a proper ratio and keep the water to a reasonable level enough to work it but not so much as to make it soup it will be just fine. In applications where a larger amount of water is needed to make it flow as in grouting block cells or a pump mix the cement content is upped to compensate.
If you are into sculpting with concrete you may want to google "papercrete"
this is basically paper mache' using cement as the binder. I have been toying with different mixes recently for a wall at my house, the results are impressive, the supposed R-value is 2-3 per inch. This is an Excellent medium for sculpting and the best part is it cost pennys to make.
It has been in use in the US for years and many, many homes..yes, whole houses have been built out of it.

[Archena]

Thanks, A!

[Archena]

Papercrete links:

ArchitectureWeek - Building - Building with Papercrete - 2002.1113

September, 2007 Papercrete Workshops and Papercrete Construction, Papercrete Information

Papercrete - Wikipedia, the free encyclopedia

[Frances]

Thank you for the answers.

That sounds really cool, I'll definitely have to try Papercrete!!

Frances

[barbarian]

Adding (water based) latex paint to your batch of concrete will not only color it but also make it more tolerant to ice and cold it's kind of like an acrylic fortifier with the added bonus of the color I have done some experimenting with it even to brushable consistency and it's very impressive I did my whole porch with a mix of latex and portland cement, squeegeed to about 1/4" and carved a tile like pattern for a finished look similar to terracotta. Now I wonder what it would happen if the latex is mixed to refractory concrete and used to finish a oven dome...

[Mojoe]

Latex paint, sounds interesting. For colored masonry there are two primary types of pigment used in blending colored masonry products, natural earth and synthetic. We use five different colors of pigment to manufacture our 49 primary colored masonry cements; one is a natural earth (excavated in Georgia) and the other 4 are iron oxides and are considered "paint grade".