When mixing concrete on the jobsite, it's quite hard to achieve the compressive strength specified on its mix design, especially when you need around 4,000 up to 7,000 psi of compressive strength. This is where admixtures for concrete come in. Ingredients added to concrete, other than Portland cement, aggregates, or water, are referred to as concrete admixtures. While not required, they are sometimes used selectively to improve the concrete mix. Admixtures are used in concrete to alter its properties in various ways. Some common uses include improving workability, increasing or decreasing cure time, and increasing concrete strength. Admixtures can also be used for aesthetic reasons, such as to change the color of the cement. Whenever possible, concrete workability, water tightness, and strength should be achieved by selecting suitable types of ag ...