How Do Aggregate Properties Affect My Ready-Mix Concrete?

Posted by on Dec 16, 2015 in News | 0 comments

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Concrete aggregate shapes and sizes have an effect on the properties of wet, dry and cured forms of ready-mix concrete. An ideal mixture will have the right blend of workability, strength, durability and absorption for your intended project.

Aggregate size, shape and properties directly influence the workability, strength, durability and absorption rate of your ready-mix concrete. The largest concrete aggregate pieces in the mix can range from small, smooth bits to large, jagged chunks. The remainder consists of smaller pieces that act as filler between the larger chunks.

When the right mixture is selected, concrete suppliers can create your desired concrete end product with ease. The ability to select the right concrete aggregate type every time begins with learning about how the properties affect the final mixture.

Workability

The size of the concrete aggregate determines the amount of water required to make your mixture workable. Large chunks of concrete aggregate keep water requirements low due to their minimal absorption rate. As the aggregate size goes down, the mixture requires more water to suspend the particles and create a workable solution.

However, as the liquid composition increases, the strength of the final mixture decreases. When selecting an appropriate aggregate size, it is important to balance workability with strength to find your perfect mixture.

Strength

Just as large aggregate chunks increase your concrete’s strength by requiring less water in the mixture, the pieces also reduce voids, which act as weak points in your cured concrete. Although the tiny particles fill up the voids, they are just not as strong as solid aggregate.

The shape of your aggregate also plays a role in the strength of the finished concrete product. Angular aggregate offers the most strength with rounded pieces coming in a close second. The strength of your chosen concrete aggregate mixture plays a huge role in the required spacing and size of reinforcement bars when creating load-bearing structures.

Durability

Overall, the rock particles used for ready-mix concrete are selected for their high crush strength, impact value and abrasion resistance characteristics. As a result, most aggregate shapes and sizes offer high durability for a wide range of structures and other projects.

To keep durability high, avoid using flaky, elongated pieces of concrete aggregate. These irregular pieces tend to require more water in the mixture, which reduces the overall strength and durability of the final product. Furthermore, the pieces may segregate during the drying and curing process, leaving weak spots throughout your concrete.

Absorption

Even with the completion of a thorough curing and sealing process, aggregates absorb moisture, especially when saturated with water frequently or for a long period of time. Coarse aggregate mixtures tend to remain in the 1% absorption range when mixed with the proper amount of moisture for setting the concrete. Fine mixtures may soak up to 5% of standing water, even with perfect mixing ratios during the initial install.

Since the properties of ready-mix concrete have an influence on each other, it is wise to receive professional advice on aggregate size before acquiring concrete mix, especially in large quantities. A knowledgeable concrete professional can use your project assessment to identify the best concrete aggregate shape and size for each construction phase.

To get in touch with a concrete aggregate supplier in Arkansas, contact Razorback Concrete at 870-455-0700 for a free aggregate estimate.

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