What is Type II GGBS in concrete? Explain in details of Type II GGBS in concrete, purpose of Type II GGBS in concrete and where to use of Type II GGBS in concrete.

Type II GGBS, or Ground Granulated Blast Furnace Slag, is another type of supplementary cementitious material used in concrete. It is also known as low heat GGBS because it generates less heat during the hydration process compared to other types of GGBS.

The purpose of Type II GGBS in concrete is similar to that of Type I GGBS, which is to replace a portion of the Portland cement in the mix. When used in concrete, Type II GGBS reacts with the calcium hydroxide in the cement to form additional calcium silicate hydrate, which improves the strength and durability of the concrete.

Type II GGBS is particularly suitable for use in concrete applications where a low heat of hydration is required. This can include:

1. Large concrete pours: In large concrete pours, the heat generated during the hydration process can cause cracking and other problems. The use of Type II GGBS can help to reduce the heat of hydration and minimize these issues.
2. Mass concrete: Like Type I GGBS, Type II GGBS is also used in mass concrete applications, such as bridge piers and dam construction, to reduce the risk of thermal cracking.
3. Infrastructure projects: Type II GGBS is often used in infrastructure projects, such as highways and airport runways, where a low heat of hydration is required to ensure the durability and longevity of the structure.
4. Precast concrete: The use of Type II GGBS in precast concrete can reduce the risk of cracking and improve the overall quality of the finished product.

The use of Type II GGBS in concrete offers several benefits, including:

1. Low heat of hydration: Type II GGBS generates less heat during the hydration process compared to other types of GGBS, which can help to reduce the risk of cracking and other issues.
2. Improved durability: Like Type I GGBS, the use of Type II GGBS in concrete can improve the long-term durability of the structure.
3. Cost savings: The use of GGBS in concrete can reduce the overall cost of the project, as GGBS is often less expensive than Portland cement.
4. Improved workability: Type II GGBS can improve the workability of concrete by reducing the water demand and increasing the flowability of the mix.

Overall, the use of Type II GGBS in concrete is a sustainable and cost-effective solution for improving the durability and performance of concrete structures, particularly in applications where a low heat of hydration is required.