Recycling lime sludge from CPDC an-shun site as coarse aggregates through cold-bonding technique

This paper shows that a new approach (i.e. cold-bonding technique) to recycle uncontaminated and innocuous lime sludge as coarse aggregates. The cold-bonding technique incorporates the principles of the cement chemistry and composite material to develop recycling coarse aggregates. Herein lime sludge was regarded as the main materials to produce recycling coarse aggregates, which meet the specifications of green building materials in Taiwan, using the cold-bonding technique instead of sintering method in light of the issues of reduction of waste, energy, and CO₂ footprint. The results show that the specific gravity (in the oven-dry state, OD) of recycling coarse aggregate is in the range of 1.20 to 1.23; the absorption capacity is in 40.0 to 44.6 %; the dry loose density (i.e. unit weight) is 811 to 837 kg/m³; the single particle compressive strength at 28-day is in the range of 17.8 to 20.4 MPa; the particle cylindrical crushing strength ranges from 27.9 to 33.8 MPa; other characteristics also satisfies ASTM C33. The developed recycling coarse aggregates could increase the reuse and recycling of lime sludge, reduce the energy consumption and CO₂ footprint, and diminish the impact on the environment and future generations.