In concrete, aggregates can change many aspects of the concrete from strength to work-ability; with concrete each particle has to be coated by cement paste. The surface area of the aggregates is what determines how much paste is required. The larger the particle the more volume it will take up. With larger particles the total amount of cement and water required to hydrate the cement is less than with smaller particles, like sand. This will lower the water/cement ratio. By using larger aggregate in the concrete mix the cost of producing the concrete is reduced. A proper mix will have enough rock to increase the strength, and economy of the concrete, while keeping it workable. Too much rock will make the concrete difficult to finish properly. All of our mixes have been tested for strength and work-ability, to provide a mix for every use.

At Pocatello Ready Mix our aggregates are required to meet certain standards to be used in Concrete. All of our concrete aggregates meet or exceed the ASTM C33 standards and are verified at least once a year, and more often if required.

The concrete sand is 100% smaller than 3/8”. 50-85% of the sand is to be larger than 1.18mm, 10-30% larger than .3mm, 2-10% larger than .15 mm, and 0-4% larger than .075mm. We also have a Roberts sand that can be blended with the concrete mix to improve finishing, though it isn’t regulated under state specifications.

The ¾ minus rock is also meets the state specification. 100% is smaller than 25mm, 80-100% is larger than 19mm/3/4”, 10-40% is larger than 9.5mm/3/8”. And 0-4 is larger than 4.75mm. The concrete sand and ¾ minus are the main ingredients in concrete, and are the main aggregates we carry.

These different aggregates consist of Coarse Sand, ¾ minus rock, Fine sand, and 3/8 rock. Our aggregates come from pits within southeast Idaho.