Recycling of waste river sludge into unfired green bricks stabilized by a combination of phosphogypsum, slag, and cement
Recycling of waste river sludge into unfired green bricks stabilized by a combination of phosphogypsum, slag, and cement
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DOI：
10.1016/j.conbuildmat.2020.120666
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发表时间：
2020-11-10
影响因子：
7.4
通讯作者：
Ahmad, Muhammad Riaz
中科院分区：
文献类型：
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作者：
Maierdan, Yierfan;Haque, M. Aminul;Ahmad, Muhammad Riaz
本研究旨在利用高含水率的废河泥生产经济高效的免烧青砖。为此，创新性地采用半水合磷石膏（HPG）对水渣进行脱水，并将不同连续剂量的普通硅酸盐水泥（OPC）、偏硅酸钠（SMS）和矿渣等火山灰废弃物与水渣混合。试验结果表明，采用6%矿渣、4% OPC、6%矿渣和6% HPG配比，获得的砖体无侧限抗压强度（UCS）在31 MPa左右，表现优异。该硬质混合料的抗吸水性能和单轴比均满足国家标准的要求。此外，扫描电镜（SEM）、x射线衍射（XRD）和热重分析（TGA）通过对水化硅酸钙（CSH）和钙矾石矿物形成的微观结构进行研究，证实了砖的强度发展特性。研究结果表明，采用上述混合料制备的未烧制青砖具有经济可行性。在最佳配比下，废弃物的利用率可达96%。因此，本研究结果在污泥处理领域具有潜在的应用价值，可用于生产经济高效的绿砖。(C) 2020 Elsevier Ltd.版权所有。
The current study is taken an attempt to reuse the waste river sludge (WRS) with high moisture content in the production of cost-effective unfired green bricks. For this purpose, hemihydrate phosphogypsum (HPG) was innovatively applied to dehydrate WRS, and different consecutive dosages of Ordinary Portland cement (OPC), sodium metasilicate (SMS) and pozzolanic waste materials like ground granulated blast-furnace slag were mixed with WRS. The observed results indicated the excellent performance of unconfined compressive strength (UCS) of the brick specimens that was obtained around 31 MPa employing the combinations 6: 4 of WRS and HPG along with the 16% slag and 4% OPC. Water absorption resisting capacity and UCS of this hard mixture satisfied the requirements of the Chinese standard. Moreover, the scanning electron microscopic (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) corroborated the strength development properties of bricks through progressing the microstructures along with calcium silicate hydrate (CSH) and ettringite minerals formations. The result of this study indicated that the unfired green bricks comprising the mixtures mentioned above are economical viable. Furthermore, the utilization rate of waste materials in the optimal ratio can reach 96%. Therefore, the outcomes of this research might be a potential application in the field of sludge treatment for manufacturing the cos-effective green bricks. (C) 2020 Elsevier Ltd. All rights reserved.