Technically, yes, you can use cement without mixing it with sand, but practically speaking, it is highly ineffective and unstable for most applications.
Why Pure Cement Isn't Recommended
Using cement purely on its own results in a material with significantly different properties than the commonly used mixtures like mortar or concrete.
As noted in the reference:
- You could use pure cement, but "it would probably break just from handling it, not need to put anything on it."
- Cement by itself "has a very very limited flexural strength."
- Even a cement mortar made with sand and cement would be very weak compared to concrete.
This means a material made of just cement binder would be brittle and lack the structural integrity needed for building or repair work.
Here's a breakdown of the issues:
- Lack of Flexural Strength: Pure cement cures into a hard, but brittle, material. It has almost no resistance to bending or pulling forces (flexural strength), making it prone to cracking and breaking easily, even from minor stresses like handling or temperature changes.
- High Shrinkage: As pure cement dries and cures, it undergoes significant shrinkage. This shrinkage causes internal stresses that lead to severe cracking.
- Cost: Using pure cement is much more expensive than using mixtures that incorporate aggregates like sand or gravel, which make up the bulk of the material.
- Workability: Mixing pure cement with just water creates a paste or slurry. While useful in specific niche applications (like injection grouting or as an additive), it doesn't have the body or consistency needed for typical mortar or concrete work like laying bricks, plastering, or pouring slabs.
The Role of Sand (Aggregate)
Sand, acting as a fine aggregate, is crucial when mixing with cement to create mortar or concrete.
- Provides Bulk: Sand fills the space, reducing the amount of expensive cement needed.
- Reduces Shrinkage: The presence of sand significantly reduces the overall shrinkage of the mix during curing, minimizing cracks.
- Increases Strength (Compression): While cement provides the binder, the aggregate (sand and gravel) carries the compressive load. A well-graded aggregate mix provides internal structure and increases the overall strength of the cured material.
- Improves Workability: Sand gives the mix body and texture, making it easier to trowel, spread, and work with for specific tasks.
Comparison: Pure Cement vs. Mortar vs. Concrete
Here's a simplified comparison of how different mixtures perform:
| Mixture Type | Components | Primary Use Cases | Relative Strength (Approximate) | Practicality for General Use |
|---|---|---|---|---|
| Pure Cement | Cement + Water | Very specific grouting, thin coatings (often with additives), binder in other mixes | Very Low (Poor flexural) | Impractical |
| Mortar | Cement + Sand + Water | Laying bricks/blocks, rendering/plastering, pointing | Low to Medium (Compressive) | High (for bonding/coating) |
| Concrete | Cement + Sand + Gravel + Water | Slabs, foundations, beams, columns | High (Compressive) | High (for structural elements) |
Note: The reference indicates even mortar is relatively weak compared to other materials, highlighting the critical role of aggregates beyond just sand for higher strength applications.
Practical Implications
If you were to use pure cement paste for something like trying to fill a crack or bond two items, it would likely crack and crumble over a short period due to shrinkage and lack of strength. For almost all construction, repair, or crafting purposes where cement is involved, it must be mixed with appropriate aggregates.
Using cement without sand is not a viable method for creating durable or strong building materials.
