Concrete Basics

What is Concrete Made of

Pouring Concrete

Concrete Mix Designs

Aggregates in Ready-Mix Concrete

Building Concrete Slabs

Concrete Testing

Seasonal Pouring Tips

Repairing Concrete

Concrete Repair

Fixing Decorative Concrete

Applications

Staining Concrete

Stamped Concrete

Concrete Countertops

Concrete Patios

Concrete Floors

Commercial Concrete

Special Considerations for Exposed-Aggregate Concrete

Contractors placing decorative exposed-aggregate concrete, where appearance is a prime concern, should pay special attention to the aggregate shape, texture, color, and overall appearance to yield the best looking final product (Photo 8). When placing architectural concrete, you should test trial mixes and place mock-ups to ensure that all parties are satisfied with the materials selected.

Both gravel and crushed stone are generally acceptable for making quality concrete (Photo 9), although gravel is usually preferred for exposed aggregate. The use of recycled concrete, crushed to proper-size concrete aggregate, has also demonstrated successful performance. Recycled concrete will have a higher absorption and lower specific gravity than conventional aggregates. To produce good quality, durable concrete containing a portion of recycled concrete aggregate often requires trial concrete mixes and close monitoring of the properties of the old recycled concrete, with mix adjustments made, as needed.

Photo 8 – Exposed-aggregate concrete pavement.

Photo 9 – Both gravel and crushed stone produce quality concrete. Gravel will have a lower water demand compared to crushed stone. Gravel is preferred for exposed-aggregate concrete in walkways and decorative applications. Crushed stone will usually exhibit a higher paste-aggregate bond. Crushed stone is preferred in pavement mixes since the higher paste-aggregate bond yields higher flexural strengths (Photo courtesy of the PCA)

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