What is the main purpose of using supplementary cementitious materials (SCMs) in concrete mixes?

The main purpose of using supplementary cementitious materials (SCMs) in concrete mixes is indeed to improve workability and reduce the carbon footprint. SCMs, such as fly ash, slag cement, and silica fume, serve several functions that contribute to the overall performance of concrete.

By incorporating SCMs, the workability of the concrete can be enhanced due to their fine particles, which can help fill voids within the mix and create a more cohesive material. This can make the mix easier to place and finish, potentially reducing the need for additional water or chemical admixtures.

In terms of environmental benefits, using SCMs can significantly reduce the carbon footprint of concrete. Traditional cement production is energy-intensive and produces a considerable amount of carbon dioxide. By partially replacing cement with SCMs, the total amount of Portland cement needed decreases, thereby reducing the overall carbon emissions associated with the concrete mix. This aligns with sustainable construction practices, which aim to minimize the environmental impact of building materials.

The other options do not represent primary purposes of SCMs in concrete mixes. While weight may increase due to some materials, the focus is not on weight but rather on performance and sustainability. Similarly, accelerating the curing process isn't a typical feature of SCMs; instead, their impact