Any concrete mix is normally made up of sand and rocks of various sizes held together by a mixture of water and cement. The concrete aggregates displace a large portion of the volume of a cubic yard of concrete. Aggregate is considered inert filler but it is a necessary component that defines the concrete's thermal and elastic properties and dimensional stability. In most mixes, aggregate will account for 70 to 85 percent of the weight and 60 to 80 percent of the volume.
The gradation and overall fineness of the aggregate used will affect the physical properties and the cost of the mix. Mineralogical and physical properties of aggregation must be known before mixing concrete to obtain a desirable mixture. Properties to be considered include moisture content, specific gravity, shape and texture, size gradation, soundness, reactivity and bulk unit weight. These characteristics not only determine the concrete's strength but also its longevity at w.w. clyde.
The gradation of the aggregate or the distribution of the particles sizes should meet the specifications outlined in the "Standard Specification for Concrete Aggregates" which suggests that the gradation curve be smooth. The concrete granule gradation document suggests that the aggregate be consisted of smooth edged granules rather than angular or long and jagged grains. This is so since the shape will affect the characteristics of the wet concrete hence the final result when the concrete finally sets. The shape and texture of the aggregate affects the properties of fresh concrete more than hardened concrete. Read http://www.huffingtonpost.com/news/green-building/ for tips in creating eco friendly houses.
The surface texture of the aggregate can either be rough or smooth. A surface that is smooth will improve the workability but a surface that is rough generates a strong bond between the paste and the aggregate creating a higher strength. Crushed stone produces much more angular and elongated aggregate, which have a higher surface to volume ratio better bond characteristic but needs more cement paste to produce a workable mixture. Size or grading distribution of aggregate is an important factor because it determines the paste requirement for workable concrete.
The total surface area to be covered and the amount of void spaces to be filled is what determine the amount of concrete paste needed. The space to be filled up will not only determine how much concrete you use but how rough you can have it since bigger volume surface can take two to three layers of different coarseness concrete without breaking the quality or inflating your budget.
The moisture content of an aggregation is an important factor when developing a proper structural concrete ratio. Using the right amount of water will not only give the mix the right stickiness and workability but also alter the way it dries up hence its strength. Finally, aggregate are most commonly known to be inert filler in concrete but it has a large impact on the economy of concrete given the different properties it has shown.