Effect of construction and demolition waste on the long-term geo-environmental behaviour of cemented paste backfill

Yılmaz T., Erçıkdı B.

INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY, cilt.19, sa.5, ss.3701-3714, 2022 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 19 Sayı: 5
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1007/s13762-021-03359-2
  • Dergi Adı: INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), Biotechnology Research Abstracts, CAB Abstracts, Compendex, Environment Index, Geobase, INSPEC, Pollution Abstracts, Veterinary Science Database
  • Sayfa Sayıları: ss.3701-3714
  • Anahtar Kelimeler: Construction and demolition waste, Geo-environmental behaviour, Heavy metal, Groundwater quality, Microstructure, Cemented paste backfill, ACID-MINE DRAINAGE, RECYCLED CONCRETE, GROUNDWATER, LIMESTONE, STRENGTH, SULFATE, RICH, ASH
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

The construction and demolition waste (CDW) could be used as backfill material to fill the voids created during the ore production in underground mining. However, there is a need to clarify the impact of CDW on groundwater pollution when it is used as backfill material in cemented paste backfill (CPB) of sulphide-rich tailings (S-rT). This study presents the influence of CDW on the long-term geo-environmental behaviour of CPB samples (CPBs) when used as replacement (10 wt.%) to S-rT. For this reason, the dynamic-tank leaching test was conducted on CPBs and pH, conductivity (Ec), sulphate (SO42-) and heavy metals (HMs) analyses were executed for leachates over 30-360 days of leaching period. The effects of mineralogy and microstructure on the geo-environmental behaviour of CPBs were also analysed via X-ray fluorescence (XRD) and mercury intrusion porosimeter (MIP). The utilisation of CDW in CPB mixtures was found to reduce the SO42- release (up to 13.89%), neutralise the acid generated and lower the Ec (up to 22.16%). Furthermore, the HMs releases (except As, Cu and Zn) were prevented (Ni and Cr) or reduced up to 92%, which is compatible with the improved CPB microstructure. Only the release of arsenic (As) exceeded the limit value for groundwater in CPB of CDW leachate. These findings suggest that not only the cost, strength and stability but also the impact on groundwater pollution should be considered when disposing of CDW as CPB material in underground voids.