Improving the Quality of Mixed Recycled Coarse Aggregates from Construction and Demolition Waste Using Heavy Media Separation with Fe₃O₄ Suspension

Table 1

Minimum criteria for recycled aggregate for various applications.

National standard or recommendation	RCA type	Absolute dry density (g/cm^3)	Absorption capacity (%)	Note
AS 1141.6.2 [4]	Class 1A	≥2.1	≤6	Well graded RCA W/brick content < 0.5%
	Class 1B	≥1.8	≤8	Class 1A RAC mixed W/crushed brick < 30%
DIN 4226-100 [6]	Type 1	≥2.0	≤10	Concrete chipping + crusher sand
	Type 2	≥2.0	≤15	Construction shipping + crusher sand
	Type 3	≥1.8	≤20	Masonry chipping + crusher sand
	Type 4	≥1.5	No limit	Mixed chippings + crusher sand
JIS A5021, 5022, and 5033 [7–9]	Class H			No limitations and segment for concrete and structures W/nominal strength 45 MPa or less
	Coarse	≥2.5	≤3
	Fine	≥2.5	≤3.5
	Class M			Members not subjected to drying or freeze-thawing action
	Coarse	≥2.3	≤5
	Fine	≥2.2	≤7
	Class L			Backfill concrete, blinding concrete, and concrete filled in steel tubes
	Coarse	No limit	≤7
	Fine	No limit	≤13
KS F 2573 [5]	Coarse	≥2.5	≤3	Members W/a nominal strength 27 MPa or less
	Fine	≥2.2	≤5
RILEM [3]	Type 1	≥1.5	≤20	Aggregates from masonry rubble
	Type 2	≥2.0	≤10	Aggregates from concrete rubble
	Type 3	≥2.5	≤3	Natural (≥80%) + recycled (≤20%) aggregate