White Portland cement is essentially the same as grey cement except that it has a white colour produced by iron and manganese metal oxides. It is primarily produced in the specifications of Type I and Type III. White Portland cement is used in exacting architectural and artistic applications, and its final mixture and colour depend on added pigment; colour; cleanliness; amount and size of mixed-in aggregates; and proportion of water added.
Choose your application. Type I cement is used for general-purpose projects. Type III cement is used when early high strength is needed.
Choose your fine aggregate. For brightest applications, use white pool sand or silica sand. Check with your local distributor to see what types of white sand aggregates are available.
Choose your coarse aggregate. Stones or gravel strengthen concrete.
Measure out the cement. The cement should make up about 10 per cent to 12 per cent of the final mix. Each batch you use should be made exactly the same way. If you are going to need more than one batch, make sure you know exactly how much of each ingredient goes into each batch.
Add the pigment. Refer to manufacturer's specifications for how much pigment to add to the mixture.
Add the fine aggregate. Use about 1/4 fine aggregate for the strongest concrete. Mix the fine aggregate thoroughly into the cement with a shovel or cement mixer.
Add the coarse aggregate. Mix this in with the cement and fine aggregate. Coarse aggregate should be approximately 40 per cent of the final mixture. For casting sculpture or fine detailed structures, coarse aggregate can be replaced with more fine aggregate.
Add the water. Water should be about 15 per cent of the final mixture. Mix thoroughly with a shovel or cement mixer. If the mixture is crumbly, add more water until the consistency is even.
- To know the exact final colour and texture of your finished concrete, make a small test batch and let it dry for more than 24 hours. If it is not the right colour or texture, you can change the aggregates or pigments until you get what you want.
- There are a variety of additives for concrete to change the strength, texture and finish. Concrete is also commonly sealed. All of these materials might change the final look of your concrete, so test a batch before proceeding with an entire project.
- If you are making a quick batch in a wheelbarrow, use one part cement, two parts sand, three parts gravel. Mix the dry materials and add water, mixing until it no longer crumbles off the sides of the wheelbarrow and is a uniform consistency.
- Cement powder can irritate skin, eyes and lungs. Wear protective clothing and avoid breathing the dust.