When looking to complete a project using cement, the question often arises about whether a project can use only pure cement. Understanding the properties of cement and the aggregates mixed in to conjure up concrete can help answer whether or not pure cement is appropriate for a job.
One can use pure cement, but it won’t be as strong as concrete due to a lack of aggregates. The compressive strength of pure Portland cement typically does not exceed 3500 psi, even after 28 days of curing. Concrete, however, can exceed 10,000 psi with the proper additives.
Cement is like a glue that binds the sand and stone aggregates added to make concrete. The bulk of the strength of concrete is not in this bond but the aggregates themselves.
We’ll dive a lot deeper a little further into this article, so keep on reading. But before we do, have you wondered yet why pure cement couldn’t take as much compression force as concrete? Let’s find out!
Is Pure Cement Stronger Than Concrete?
Pure cement is not stronger than concrete. The strength of concrete resides in the matrix of strong aggregates bound in place by the cement (powdered clinker, gypsum, and added water). But, can you use pure cement?
As discussed above, cement is the glue that binds concrete together. But it is not the strength of the concrete. The strength of concrete comes from the strength of the aggregates used to make the material.
However, Portland Cement is a finely ground powder that is created by grinding clinkers and adding gypsum. With such a fine, baby-powder-like consistency, the cement is not nearly as strong as the stone and sand particles added to make the final product, concrete.
The real strength of concrete is determined by the mixture of aggregates in the product. That is, the ratio of cement to aggregate to water. Ideally, there should be about 60% – 75% aggregate, 10% – 15% Portland Cement and water.
Can I Mix Cement With Just Water?
A similar question to our main topic here, as discussed, we’ll dive a little deeper into the subject.
Cement may be used purely with water to form a grout. The finished product’s compressive strength will be significantly less than if it were made of a mixture of cement and aggregate.
Another thing to consider about cement is that the cost of pure cement compared to concrete cost is quite different. Using pure cement is not only creating a weaker building material than concrete, but it is also significantly more expensive pound for pound.
When you mix cement with water and no aggregate, the finished product is not only weaker in terms of the compression strength mentioned above it also has a much higher tendency to crack or fracture during the drying process.
On the other side of the equation, should you mix too much aggregate and not enough water with the cement, a honeycomb-like finished product is created. This porous concrete would be weak and not have much compression strength to speak of to maintain any longevity.
To conclude, cement mixed solely with the water will be a lot easier to apply and form but will be significantly weaker than it’s concrete counterparts.
Should I Use Pure Cement Or Concrete?
Depending on the scope of work, pure cement may be required. Most jobs involving these building materials call for concrete, a much stronger finished product than cement alone. But that isn’t to say that pure cement cannot take the form of grout or small patch repair.
Cement is an ingredient of concrete. Sand, pebbles, and stone aggregates constitute the remaining typical ingredients of concrete. Cement is made of gypsum and clinker, ground to a fine powder.
When water adds to cement, it becomes a paste that can fill cracks and do minor repairs to concrete surfaces. However, as mentioned earlier, cement alone does not have the compression strength that you will find concrete has. But if the concrete isn’t the solution, then cement might be able to do the job on its own.
Commonly used in situations where concrete is not feasible, such as underwater applications, pure cement finds its place.
Can I Make Concrete With Just Sand And Cement?
Standard concrete is a mixture of Portland cement and aggregate commonly in the sand and small pebbles forms. Water is a requirement to bind the cement to the aggregate to form the finished product: concrete.
When you add just sand to cement and no stone, the finished product is known as mortar. Often employed to bond brickwork, mortar is strong, but not as strong as concrete.
So, adding sand to cement can be done if you need a smooth, easy to work with wet mixture, but if you want it to have strength, add stone to the mix to make concrete.
Which Sand Is Best For Concrete?
Two commonly used types of sand are M-Sand and River Sand. Both of these types are common for concrete. However, the M-Sand, which is artificial sand made by crushing aggregates, is superior sand for concrete use.
Another consideration for the sand type is the amount of clay. Sand with higher levels of clay is often referred to as ‘fatty’ sand. When mixed with cement, the mixture gains a greater ‘stickiness’ than its clay-free counterparts.
A higher clay content works well for use in making mortars and grouts where the application may be such that one needs the extra cohesion to hold the wet mortar in place. An example of this would be patching a vertical concrete wall. A sticky mortar would be better suited for this application than a runny mortar or does not stick well.
Can I Mix Cement With Soil?
If you’ve done any online investigations regarding soil and cement, you’ll find some information that, at first glance, can be misleading.
You can mix cement with soil, but the result will be an inferior quality product. There will be a lack of compression strength, and water will erode and damage the finished result.
There is a cement product known as soil-cement, and this is what I was referring to when I stated that an online search could be misleading at first glance. Soil-cement is used widely across North America and abroad for roadways and many other construction projects. But despite the name, it isn’t actual soil like that in your garden, which makes the bulk of soil-cement.
When referring to soil-cement, the idea is that several different types of aggregates might make use of the building material. These may contain certain organic matter levels, but for the most part, ‘clean’ aggregates are preferred.
The cement industry often uses soil-cement as a base for roadways, loading zones, and more according to PCA – America’s Cement Manufacturers. The ‘soils’ used are often by-products of mining, such as screenings or even re-claimed roadways. The ‘soil’ is not dirt that you would plant your shrubs into in the spring.
Can I Pour Concrete On Dirt?
Pouring concrete directly on top of the dirt is possible, but ill-advised. Dirt can quickly fill with cavities created by run-off from heavy rainfall. With a concrete slab floating on top of the dirt, mini rivers of water under that slab can erode channels and voids in the dirt underneath.
If you decide you’re going to go ahead and keep a dirt base, there are a couple of things you can do to improve your odds of success better. First, make sure the dirt packs down well.
Next, lay at least two inches of sand or gravel on top of the dirt and pour the concrete on top of the sand or gravel. It will allow a layer under the concrete where water can quickly drain without significant erosion eating away at your concrete’s base.
Can I Use Pure Cement? – Conclusions
Now that you know all about Portland cement, mortar, and concrete, you should be in a well-prepared position for a project involving these materials. Using cement alone works well for small patch and repair work, as the powder forms a grout-like product before it cures. Cement with sand creates mortar. The sand can be of various types, but types including higher clay particulates will cause the mortar to be more sticky than made with clay-free sand.
Cement added to a mixture of sand and stone, pebbles, or other particulates creates the most robust concrete forms once the proper amount of water completes the mixture and curing finishes. And now that you know all about cement and concrete, what type will you use on your project?
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