Why Do You Put Lime in Cement? Benefits and Drawbacks Covered

Lime has been used in construction for centuries, and for good reason. It has a number of properties that make it an ideal material for use in mortar and concrete. Adding lime to cement can be beneficial and it helps to increase sustainability, durability, and so on.

In this article, we’re going to dig deep into the world of cement and lime, exploring the reasons behind adding lime to cement mixtures and whether it’s truly beneficial. So, grab your hard hat, and let’s dive into the world of lime-infused cement!

Is Adding Additional Lime Beneficial?

Yes, adding lime to cement can be highly beneficial for various reasons. This combination of lime and cement is often referred to as lime-cement mortar or simply lime mortar. However, it’s essential to understand the science behind it and when it’s most advantageous to use lime in cement mixtures.

To explain further, we’ll break down the benefits and drawbacks of incorporating lime into cement mixes. 

1. Improved workability 

Lime makes mortar and concrete more workable by reducing the amount of water needed to mix the mix. This makes it easier to spread and apply the mix, which can be especially beneficial in cold weather or when using a high percentage of coarse aggregate.

2. Increased water retention 

Lime helps mortar and concrete retain water, which is important for proper curing. This is because lime creates a more porous mix that allows water to be absorbed more slowly. This can be especially beneficial in hot weather or dry climates, where mortar and concrete can dry out too quickly and become weak.

3. Improved durability

Lime can improve the durability of mortar and concrete by making them more resistant to sulfate attack and efflorescence. A sulfate attack is a chemical reaction that can occur when mortar and concrete are exposed to sulfates in the soil or water. This reaction can cause the mortar and concrete to crack and deteriorate. Efflorescence is a white or gray powder that can form on the surface of mortar and concrete when salts are brought to the surface by moisture. Lime can help to reduce the risk of both sulfate attack and efflorescence.

4. Increased sustainability

Lime is a more sustainable material than cement, as it produces less carbon dioxide during production. This is because lime is made from limestone, which is a naturally occurring material. Cement, on the other hand, is made from calcium carbonate, which is mined and then processed at high temperatures.

Drawbacks of Adding Lime in Cement

Here is a more detailed look at the drawbacks of adding lime to cement:

1. Reduced strength

Lime can reduce the compressive strength of mortar and concrete. This is because lime is not as strong as cement. However, the reduction in strength is typically not significant, and it can be offset by using a higher-strength cement or by adding more cement to the mix.

2. Increased shrinkage 

Lime can increase the shrinkage of mortar and concrete. This is because lime creates a more porous mix that allows water to evaporate more easily. Shrinkage can lead to cracking, so it is important to use the correct amount of lime and to take steps to reduce shrinkage, such as curing the mortar or concrete properly.

3. Cost

Lime can be more expensive than cement, so adding additional lime can increase the cost of the project. However, the increased cost is often offset by the benefits of adding lime, such as improved workability and durability.

Where Lime should be Added in Cement: In Mortar or Concrete

Now that we’ve explored the advantages and disadvantages of adding lime to cement, let’s tackle the question of where it’s best to incorporate lime—mortar or concrete

Mortar Lime is commonly added to mortar mixes. It enhances the workability of the mortar, making it easier to lay bricks or stones. It also contributes to the mortar’s longevity, ensuring that your masonry work remains strong and resilient.

Concrete While less common, lime can also be added to concrete mixes. This is typically done when you need improved workability, better adhesion, or enhanced durability in your concrete structures.

In both cases, the addition of lime should be carefully measured and controlled to achieve the desired results.

Final Thoughts

In the world of construction, the decision to add lime to cement is not a matter of tradition but one of practicality and performance. Lime can significantly enhance the workability, durability, and adhesion of your cement mixtures, making it a valuable tool in the construction toolbox. However, it’s essential to weigh the benefits against the costs and consider the specific needs of your project.

So, the next time you see a construction project involving lime-infused cement, you’ll know that it’s not just a whimsical choice but a calculated decision to create structures that stand the test of time. Happy building!

Frequently Asked Questions and Answers

Q. Is lime a common additive in modern construction?

Yes, lime remains a valuable additive in modern construction due to its ability to enhance workability, durability, and adhesion in cement mixtures.

Q. Can lime-infused cement be used for eco-friendly construction?

Absolutely. Lime production has a lower carbon footprint compared to other additives, making it a sustainable choice for eco-conscious construction projects.

Q. Where can I purchase lime for construction purposes?

Lime can be purchased from construction supply stores, and it’s available in various forms, including hydrated lime and quicklime, depending on your project’s requirements.