**6. Conclusion**

116 Sintering of Ceramics – New Emerging Techniques

**Age (days)**

Fig. 13. The single particle compressive strength growth of recycling coarse aggregates with

According to an approach to estimate energy consumption, CO2 emission, and prime cost of sintering recycling aggregates (Shiao et al., 2002), the cold-bonding recycling aggregates also was evaluated and compared with primitive and sintering aggregate. Table 6 shows the comparisons of properties, energy consumption, CO2 emission, and prime cost of three various aggregates (primitive, sintering, and cold-bonding recycling aggregates). The results show that the recycling aggregate produced by using cold-bonding technique can reduce about 65 % CO2 footprint than using sintering technique (Shiao et al., 2002). The prime cost of sintering recycling aggregate is 5 to 6 times higher than cold-bonding recycling aggregate. Even if the prime cost of cold-bonding recycling aggregate is lower than the primitive aggregate in Taiwan. The gradation of cold-bonding recycling aggregate is controllable and its single particle compressive strength at 91-day is 1.5 to 3 times higher than sintering

Item Aggregate type

Gradation Incontrollable Single size Controllable

strength (MPa) 60.0 to 500.0 <7.0 10 to 22

Energy consumption Low High Low CO2 emission (kg/m3) - 62.89 20.59 Cost (NTD/ m3) 850 4,000 650

L-50 L-100 L-200

Primitive Sintering Cold-bonding

1 10 100

**Single particle compressive strength (MPa)**

0

**5.3 Comparisons of various aggregates** 

lime sludge.

recycling aggregate.

Single particle compressive

Table 12. Comparisons of various type aggregates.

5

10

15

20

25

