REPEATED REUSE OF DEMOLISHED CONCRETE WASTES AS AGGREGATES

Concrete industry has come to the stage of reconsidering the effective way of using natural quality aggregates as well as the technology for reusing demolished concrete as aggregates. The annual cement output has reached 730 million tons in China and around 4 billion tons of concrete was fabricated last year, which equals a need for about 3 billion tons of aggregates. This paper discusses the possibility of repeated reuse of crushed concrete as recycled aggregate and introduces the preliminary results of tests. Different proportions of recycled aggregates were used to replaced natural aggregate, the workability of fresh concrete and properties of hardened concrete were studied and compared with reference concretes. Recycled aggregates from original high strength concrete could be used to make relative high strength concrete, recycled aggregate from crushed low strength concrete could only be used to make lower strength concrete. A digital camera was employed to take the pictures of broken surfaces of concrete specimens. Test results showed that crushed concrete can be used as recycled aggregate to make new concrete, but the reuse of concrete as recycled aggregate is influenced by the quality of the original concrete.

• INTRODUCTION

• MATERIALS AND EXPERIMENTS

• RESULTS AND DISCUSSION

• CONCLUSIONS

• REFERENCES