To create a superior concrete mix, the aggregates used must be clean, hard, and strong particles that are free of any absorbed chemicals or coatings of clay and other fine materials that could cause deterioration. This article will provide a summary of the most important factors to consider when selecting and dosing concrete aggregate. The term concrete aggregates encompasses a variety of products, but they are generally divided into coarse-grained and fine grades, such as gravel and crushed stone. Both are generally acceptable for producing quality concrete (Photo), although gravel is usually preferred for exposed aggregate.
Using larger coarse-grated aggregates typically reduces the cost of a concrete mix by decreasing the amount of cement needed, which is the most expensive ingredient. Recycled concrete is created by breaking, removing, and crushing existing concrete to a desired size. Photo 7 - The size distribution of fine to coarse-grained aggregates plays an important role in the workability and performance of concrete. If their absorption is not satisfied, these sponges steal water from the designated amount of mixing water, reducing concrete settling.
Creating good quality, durable concrete containing a portion of recycled concrete aggregate often requires testing different concrete mixes and closely monitoring the properties of old recycled concrete, with mix adjustments made as needed. The use of non-potable water or water of unknown purity can jeopardize the quality and workability of concrete. Aggregates are a broad category of materials, such as sand, gravel, crushed stone, slag, and recycled concrete. Changes in gradation, maximum size, unit weight, and moisture content can alter the character and performance of the concrete mix.
Although the terms cement and concrete are often used interchangeably, cement is actually an ingredient in concrete. Concrete aggregates are produced to Australian standards (AS 275) or to more specific customer requirements. Recycled concrete will have a higher absorption and a lower specific gravity than conventional aggregates. When selecting an aggregate for your next project, it's important to consider all of these factors to ensure you get the best possible results. The quality of your aggregate will have a direct impact on the strength and durability of your finished product.
Make sure you choose an aggregate that meets your needs and is suitable for your application.