Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
J Hazard Mater. 2019 Apr 15;368:689-697. doi: 10.1016/j.jhazmat.2019.01.112. Epub 2019 Feb 1.
In this study, concrete slurry waste (CSW) and fine incineration bottom ash (IBA) (<2.36 mm) were innovatively valorized to produce cold bonded lightweight aggregates (CBLAs) through a pelletizing method. The contribution of CSW to CBLAs as a fresh recycled cementitious paste was investigated and the influences of adding various binders (OPC, GGBS, lime, silica fume) on the properties of CBLAs were explored. Meanwhile, the leaching behaviours of the produced CBLAs were further assessed. The experimental results showed that CSW and IBA had a good compatibility to produce CBLAs by the pelletizing method. The use of fresh and workable CSW collected from ready-mixed concrete plants as a recycled cementitious paste could effectively bond the IBA particles. Due to the residual hydration behaviour of CSW, the produced CBLAs, even without additional binders, had good mechanical properties. The use of small percentages of cement and GGBS as additional binders could significantly increase the strength of CBLAs, while the use of lime and silica fume only showed slight improvement due to the high porosity induced. Moreover, it was found that using GGBS which could react with Ca(OH) in CSW to lower the pH benefited the immobilization of heavy metals in CBLAs.
在这项研究中，创新性地利用混凝土浆废料（CSW）和细焚烧底灰（IBA）（<2.36 毫米）通过制粒法生产冷固轻集料（CBLAs）。研究了 CSW 作为新鲜再生胶凝浆体在 CBLAs 中的作用，并探讨了添加各种粘结剂（OPC、GGBS、石灰、硅灰）对 CBLAs 性能的影响。同时，还进一步评估了所生产的 CBLAs 的浸出行为。实验结果表明，CSW 和 IBA 通过制粒法具有良好的相容性，可以生产 CBLAs。使用从预拌混凝土厂收集的新鲜且可使用的 CSW 作为再生胶凝浆体，可以有效地粘结 IBA 颗粒。由于 CSW 的残余水合作用，即使没有额外的粘结剂，所生产的 CBLAs 也具有良好的机械性能。少量水泥和 GGBS 作为附加粘结剂的使用可以显著提高 CBLAs 的强度，而石灰和硅灰的使用仅由于高孔隙率而略有提高。此外，发现使用 GGBS 与 CSW 中的 Ca(OH)反应以降低 pH 值有利于重金属在 CBLAs 中的固定。
