Secondary and Recycled Aggregates

BRMCA Member Companies have the technical expertise to produce and supply concrete containing a range of secondary and/or recycled aggregate, and at a range of percentage replacement levels (i.e. replacing primary aggregate).

BRMCA advice to specifiers is engage with ready-mixed concrete companies to ensure the availability, best and most effective use of secondary and recycled aggregate prior to specification. The Area/Regional, or in some cases National Technical Manager/Director should be contacted in this regard.

For most practical applications recycled aggregates should only be introduced as a replacement for the coarse aggregate element of fresh concrete and at a percentage that does not adversely affect the concrete fresh or hardened properties.

Consideration should be given as to whether or not the introduction of secondary and/or recycled aggregate into concrete will provide a more sustainable and environmentally sound project, as their introduction into other forms of construction material and applications may provide more viable options in both economic and environmental terms. 

Consideration should be given to:

• Availability and subsequent transportation distance
• Increase in cement/combination content of concrete when secondary or recycled aggregate is introduced as a result of the potentially wide variation in material quality.
• Production, processing, screening, washing and grading of recycled materials to improve their consistency and quality to a level that they may be considered suitable for introduction into concrete.
  Note - Alternative uses may require significantly less processing.

Technical considerations include:

• Be in accordance with the requirement set out in the British Standard for Concrete, BS 8500.
• Recycled concrete aggregate may not be suitable for aggressive ground or severe freeze-thaw conditions (see BS 8500).
• Recycled concrete aggregate may increase the creep of hardened concrete.
• Recycled aggregates (excluding recycled concrete aggregate) require the specifier to include source specific requirements with respect to ASR and sulfate limits (see BS 8500).

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