Instructables

Can portland cement be mixed without sand or gravel?

I'm planning to switch from wood to cement because we are soon moving into a condominium where noise should be kept to a minimum. If yes, what is the ratio of water to cement? if no, can i mix it with sand only and what is the ratio. Thanks

If I was making stepping stones of a purely decorative nature, would I be able to mix just the cement & water. and if so, what is the best ratio?

Don't worry about ratios. Portland cement is anhydrous and forms a hydraulic cement when water is added. This called hydration (hardening) of the concrete

When using Portland cement alone, you only need add enough water to completely hydrate it, causing the clinker sulphates and gypsum to dissolve; producing a pourable alkaline, sulfate=rich solution. Use enough water to achieve the desired consistency for pouring.

Dry powdered pigments can be added before the water, If you are going to be walking about bear footed, choose a light colored pigment. The amount of heat gain between a white colored stone and a light grey is startling..

Decorative stones such as quartzite, small river pebbles or crushed glass are sometimes added to the surface of concrete for a decorative "exposed aggregate" finish, I live near the Pacific Coast and use crushed glass that has been submerged on the beach in a nylon bag with a little bit of sand. I wind up with polished glass pebbles.

If you are going to be using these stones where they are exposed to high levels of ultra-violet light and freezing winter temperaturs, you might consider adding an adipate-based plasticizer.

It's a wee bit more than you asked but I think fore knowledge is better than hind sight. I hope that this helps.

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Re-design3 years ago
What are you going to do with it? Tell us what your plans are and we might be able to send you in a different direction.
lemonie3 years ago

You can, but cement on it's own is not a good material for anything really.
What is wrong with mixing in sand (which is much cheaper than cement)

L
caarntedd3 years ago
Yes.
Burf3 years ago
Not knowing what you are going to do with it makes giving you a useful answer difficult, if not impossible, so I can only give you some information.
Aggregate is added to cement to give it strength. Without aggregate, you're basically going to have grey plaster with little inherent strength for both tension and compression. Even small aggregate, sand and pea gravel, will make a significant difference in the strength.
Aggregate to cement proportions should be about 3 parts aggregate to 1 part cement by volume for field/hand mixed concrete. Only enough water should be added to afford workability and eliminate voids in the mix. The less water you use, the higher the strength of the cured concrete.
There are additives you can mix with the concrete for additional workability and strength. Check with your retailer for information on this.
Last, you can buy ready mixed, dry concrete, usually called Reddy-mix and Sackcrete. Easier to use but significantly more expensive than buying the components and preparing the mix yourself.
rickharris3 years ago
Mmmm? You can, and people do mix cement with sand (often by hand) 6:1 gives the mix generally used for mortar to hold bricks together.

Do I really understand that you can see yourself mixing cement inside your house?? Tolerant wife is all I can say.
orksecurity3 years ago
I haven't worked with cement enough to have a valid opinion, but I did want to point out that moving into an apartment/condo doesn't mean you have to give up working with wood. Hand tools, screws, and some power tools (electric drill, some sanders, ...) are much quieter than a full-scale powered woodshop, and really can do just about everything that the fancier tools will -- they may take more time and require a bit more skill, but that means you can take more pride in the result. Even unpowered woodturning is possible, with a treadle lathe.

+1

You can whittle a stick over a waste-paper bin in almost absolute silence.