How to Make Waterproof Cement Concrete: Techniques and Additives

Waterproof cement concrete is essential for ensuring the durability and longevity of structures, particularly for flat roofs and basement walls. This article discusses the various methods and additives that can be used to enhance the water resistance of cement concrete, ensuring that your construction projects remain protected against water ingress.

Introduction to Waterproofing Methods

Waterproofing techniques vary from simple surface treatments to the incorporation of specialized additives. Different methods are suitable for different types of constructions. This section will cover four common methods and one additive-based approach.

Method 1: Rough Surfacing with Concrete

For ordinary buildings, the finishing of the roof surface is done simultaneously with the laying of the cement concrete. This involves using a cement mortar ratio of 1:4 (one part cement to four parts sand by volume).

The steps are:

Roughen the surface of the R.C.C. (Reinforced Cement Concrete) slab. Apply a concrete layer of up to 100 mm in thickness. This layer may include brickbats or a specific cement ratio like 1:2:4 or 1:6:12. Cover the surface with a suitable flooring material such as tiles, terrazzo, or Indian patent stone.

Method 2: Hot Mastic Asphalts and Jute Cloth

This method involves using hot mastic asphalt. A layer of this asphalt is applied to the roof surface. Over this, jute cloth is spread, followed by another layer of mastic asphalt. Sand is sprinkled over the entire surface to improve grip. Lead sheets can be inserted at the junction of the parapet wall and the roof for an extra grip.

Method 3: Waterproofing Compounds

There are several waterproofing compounds available in the market, such as pudlo and Impermo. These compounds can be added to the cement during construction, preventing seepage, leakage, and dampness caused by capillary absorption. The typical quantity required is around 2%, meaning a bag of cement would need approximately 10 N of such compound.

Adding Additives to Cement Mix

In addition to the above methods, you can also modify your cement mix to make it more waterproof by incorporating specific additives. Here are some techniques:

1. Use Waterproofing Agents

Chemical additives like acrylics, latex, and silicones can be added to the cement mix. These agents form a protective barrier around the cement particles, making them more resistant to water. Some available additives include:

Acrylic Coatings Latex Additives Silicone-based Sealants

These agents can significantly improve the overall water resistance of your cement concrete.

2. Use Waterproof Cement Mix

Some cement mixes are specially formulated to be more waterproof than standard mixes. Look for a cement mix that contains a waterproofing agent or is labeled as 'waterproof.' These mixes are designed to provide better resistance to water penetration.

3. Reduce Water Content

The amount of water added to the cement mix is crucial. Excess water can weaken the mixture, reducing its structural integrity. Try to use the minimum amount of water required to create a workable mixture. This ensures that the concrete maintains its strength while resisting water.

4. Apply Waterproof Membranes

If you need to create a completely waterproof surface, such as a basement wall or swimming pool, you may need to apply a waterproof membrane over the concrete. Membranes can be made from various materials including rubber, plastic, or bitumen. These materials form a protective layer that prevents water from penetrating the surface.

Conclusion

Enhancing the water resistance of cement concrete is crucial for the longevity and protection of your construction projects. By using the appropriate methods and additives, you can ensure that your structures remain dry and structurally sound. Whether you choose surface treatments, special cement mixes, or chemical additives, the key is to follow the manufacturer's instructions and consider professional advice if needed.

Keywords: waterproof cement, waterproofing agents, cement concrete