title: Innovative reuse of concrete slurry waste from ready-mixed concrete plants in construction products.
abstract: Concrete slurry waste (CSW) is generated from ready-mixed concrete plants during concrete production and is classified as a corrosive hazardous material. If it is disposed of at landfills, it would cause detrimental effects for our surrounding environment and ecosystems due to its high pH value as well as heavy metal contamination and accumulation. A new method in this study has been introduced to effectively reuse CSW in new construction products. In this method, the calcium-silicate rich CSW in the fresh state was considered as a cementitious paste as well as a CO2 capture medium. The experimental results showed that the pH values of the collected CSWs stored for 28 days ranged from 12.5 to 13.0 and a drastic decrease of pH value was detected after accelerated mineral carbonation. The theoretically calculated CO2 sequestration extent of CSWs was from 27.05% to 31.23%. The practical water to solid ratio in the fresh CSW varied from 0.76 to 1.12, which had a significant impact on the compressive strength of the mixture with CSWs. After subjecting to accelerated mineral carbonation, rapid initial strength development and lower drying shrinkage for the prepared concrete mixture were achieved.
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, Hong Kong.
authors.forename: Dongxing
authors.initials: D
authors.lastname: Xuan
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, Hong Kong.
authors.forename: Baojian
authors.initials: B
authors.lastname: Zhan
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, Hong Kong. Electronic address: cecspoon@polyu.edu.hk.
authors.forename: Chi Sun
authors.initials: CS
authors.lastname: Poon
authors.affiliation: Gammon Construction Ltd, 28th Floor, Devon House, Taikoo Place, Quarry Bay, Hong Kong, Hong Kong.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
keywords: Accelerated mineral carbonation; CO(2) sequestration; Concrete production; Concrete slurry waste