<p>Roller-compacted concrete derives its name from the construction method which is used to construct it. It's placed with conventional asphalt paving equipment,then compacted with rollers.</p>
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<p>Roller-compacted concrete has the same basic components as conventional concrete: cement, water, and aggregates, such as gravel or crushed stone.</p>
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However, unlike conventional concrete mix, it's much drier and usually stiff enough to be compacted by vibratory rollers. Typically, roller-compacted concrete is constructed without joints. It needs neither forms nor finishing, nor does it contain dowel bars or steel reinforcement.
These characteristics make roller-compacted concrete simple, fast, and economical.
For more info: Roller compacted concrete