The durability and environmental properties of self-compacting concrete incorporating cold bonded lightweight aggregates produced from combined industrial solid wastes

Several industrial solid wastes are integrally recycled to produce cold bonded artificial aggregates (CBLA) using the pelletizing technique, and incineration bottom ash fines (BAF, 0-2 mm) are innovatively used to strengthen the pellet strength. Three types of CBLAs are produced, in which BAF, nano-silica produced by olivine dissolution and polypropylene fibre are applied to improve the aggregates' properties (strength, etc.), respectively. The influence of these different types of CBLAs on the designed self-compacting concretes (SCCs) are experimental study and compared. The fresh and hardened properties of the concrete with and without CBLAs are investigated, including slump flow diameter, t500 time, V-funnel time, bulk density, flexural and compressive strength, etc. Moreover, the durability of the concretes is studied through water penetration and freeze-thaw tests. Additionally, the leaching behaviour of heavy metals and salts from the concretes are evaluated through different leaching tests according to environmental legislation. The results show that the roundish particle shape of CBLAs benefit the flow of concrete in fresh stage, and the strength of concrete with CBLAs has linear relation with its bulk density, and the cumulative mass loss profiles during freeze-thaw tests were influenced by the types of CBLAs. The leaching tests show that the concretes containing CBLAs are environmental non-hazardous.