Importance of Curing Compound

Curing Compound – Essential Chemical for Strong Concrete

Curing compound is an essential construction chemical to make concrete stronger and enhance its other properties.

Curing is all about controlling the moisture level in concrete after it is poured/placed so that the concrete’s properties are improved. Curing affects the concrete’s overall strength, durability, volume stability and water tightness. A curing chemical also helps to make the concrete resistant to abrasion and the freeze-thaw cycle as well as de-icing salts. These properties tend to be lower or diminished in concrete when curing compound is not added sufficiently.

Importance of Curing Compound

Hydration is the chemical reaction that occurs when Portland cement is mixed with water. Cement hydration allows the density, durability, and strength of the concrete to become enhanced. Appropriate hydration ensures the cement shows improved properties.

The process of hydration usually takes significant time and is not just limited to the concrete surface’s hardening. In theory, the cement hydration process can go on for years. If the cement mix has sufficient water content, then the first 3 days only allow about 30% of the hydration process to be completed. This way, it is estimated that it takes around 28 days for the concrete to be 98% hydrated.

Mostly, fresh concrete contains excessive levels of water. This water tends to get released in the first few days through the “bleeding” process and evaporation, which reduces the overall water content. With this, the hydration process slows down or stops completely. Hence, it is crucial that water evaporation is restricted to ensure long-term durability of concrete.

Excessive loss of water can cause shrinkage, which creates unwanted tensile stress within the concrete. In case the stress becomes significantly high before the concrete achieves optimal strength, it causes cracks to develop on the surface.

Use of Curing Compound

Concrete basically retains water in two different ways –

1 – Wet curing process requires keeping the concrete wet for at least 7 days. To do this, construction experts use immersion, ponding, fogging and spraying methods. Additionally, they may also apply saturated wet coverings, such as burlap sacks over the concrete surface to retain moisture for a longer time.

2 – Sealing fresh concrete surface is another way to retain water for a longer time. To do this, construction experts usually cover the concrete with impervious plastic or paper sheets. However, the most common method involves applying a concrete curing compound which forms a thin seamless film over the surface.

Both curing methods have their benefits and drawbacks. Depending on the size and shape of the concrete, availability, location and environment, you can use one or combine multiple curing methods. However, experts recommend using a high-quality curing chemical to achieve optimal strength and durability for concrete. The best way to cure concrete is to add a curing compound and flood the concrete with water. For this, you need to soak the fresh concrete surface with water for a minimum of 7 days.

It is crucial to maintain the moisture level during the curing process and avoid letting the concrete surface get dry. However, frequent watering and drying tends to damage the concrete. Hence, it is advisable to combine curing compounds with soaking.

Types of Curing Compounds

There are several types of curing compounds available on the market. For example, a membranous curing chemical comes in two types – white pigmented and clear. White pigmented curing chemicals reflect light clearly which helps to ensure complete coverage of the concrete surface. On the other hand, a clear curing compound comes with a special dye that helps to ensure complete coverage of the concrete. The dye fades away after several days and leaves the concrete surface smooth and stain-free.

Difference between Water-based and Solvent-based Curing Compounds

A good quality curing compound, such as those manufactured by Sakshi Chem Sciences Pvt Ltd are highly effective in retaining moisture in the concrete. However, the application and situation dictate the best-suited curing chemical to use. Water-based and solvent-based curing compounds can be used for interior applications. Still, there are significant differences between the two.

For instance, water-based curing chemicals have lower VOC (volatile organic compounds) and odor, hence they are more preferred for indoor applications. Experts do not recommend using water-based curing compounds in areas where the temperature can go below 50 Degree Fahrenheit before drying. This can result in cracks in the curing membrane and provide insufficient coverage. Besides, when you use water-based curing chemicals you will need to clean the surface with water and soap.

However, solvent-based curing compounds can be quickly cleaned using mineral spirits. The type of spraying equipment used to apply the two is also different.

Application of Curing Compound

It is recommended to apply curing compounds immediately following the final finish to the concrete surface, as soon as the visible sheen disappears. This ensures that the spraying will not affect the concrete surface.

Curing compounds are usually applied using power-driven or hand-held spraying equipment that has a fan-tip nozzle. However, brushes or rollers are also used, depending on the surface. Irrespective of the type of curing compound or method of application being used, you need to ensure that the curing chemical forms a thin and continuous layer over the surface to ensure optimal retention of moisture.

The best-suited curing compound depends on the level of solid particles in it. A higher number of solid particle content ensures that the layer of curing compound is thicker and stronger, which helps to retain moisture more effectively.


Optimal curing requires retaining the water level in the fresh concrete for as long as possible. For this, it is essential to choose a curing compound that forms a thick, strong and continuous layer over the concrete surface after it is applied.

Construction experts recommend using curing chemicals that contain a higher concentration of solid particles as these create a firm and seamless film upon application. This ensures that the concrete retains water for maximum duration, thus enabling the concrete to be stronger and more durable.