Mechanical, Structural, and Environmental Properties of Building Cements from Valorized Sewage Sludges

IF 7 Q1 ENGINEERING, ELECTRICAL & ELECTRONIC

Smart Cities Pub Date : 2023-04-29 DOI:10.3390/smartcities6030059

R. Zari, A. Graich, K. Abdelouahdi, M. Monkade, A. Laghzizil, J. Nunzi

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引用次数: 1

Abstract

Building materials can enable the recycling of sewage sludge from tannery wastewater treatment by infiltration/percolation over coal and clay waste. The process avoids energy-intensive operations and yields a stable and environmentally friendly product. The sludge under study is mainly composed of SiO2, CaO, Al2O3, and Fe2O3, which is convenient to replace the mortar in cement. Different mortars were made by substituting a variable amount of sludge, from 0 to 30%, into the standard cement. The microstructure and mechanical properties of the mortar specimens were characterized after curing for 7 days and 28 days. The best properties were obtained with 15% sludge. Above 15%, the strength decreases at an early stage, as confirmed by SEM and XRD analysis, with more voids and ettringites at larger sludge content. The leaching tests of the mortar confirm that the cumulative values of heavy metals are far below the Deutsch regulatory limits (NEN 7043), justifying retention of the metals in the matrix. Radiological assessment of the sludge mortars also confirms their safety with the values of naturally occurring radioactive materials, surface radon exhalation and annual effective dose far below the required limits. The study suggests that 15% sludge can be used to sustainably replace cement and meet building safety requirement standards.

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Valorized Sewage Sludges建筑水泥的力学、结构和环境特性

建筑材料可以通过对煤和粘土废物的渗透/渗滤来回收制革废水处理中的污泥。该工艺避免了能源密集型操作，并生产出稳定且环保的产品。所研究的污泥主要由SiO2、CaO、Al2O3和Fe2O3组成，便于取代水泥中的砂浆。通过在标准水泥中加入0至30%的不同量的污泥来制备不同的砂浆。在固化7天和28天后，对砂浆试样的微观结构和力学性能进行了表征。使用15%的污泥可获得最佳性能。SEM和XRD分析证实，在15%以上，强度在早期阶段降低，污泥含量越大，空隙和钙矾石越多。砂浆的浸出试验证实，重金属的累积值远低于Deutsch监管限值（NEN 7043），证明金属在基质中的保留是合理的。污泥灰浆的放射性评估也证实了它们的安全性，因为天然存在的放射性物质、表面氡的呼出量和年有效剂量的值远低于要求的限度。研究表明，15%的污泥可用于可持续地替代水泥，并符合建筑安全要求标准。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Smart Cities Multiple-

CiteScore

11.20

自引率

6.20%

发文量

审稿时长

11 weeks

期刊介绍： Smart Cities (ISSN 2624-6511) provides an advanced forum for the dissemination of information on the science and technology of smart cities, publishing reviews, regular research papers (articles) and communications in all areas of research concerning smart cities. Our aim is to encourage scientists to publish their experimental and theoretical results in as much detail as possible, with no restriction on the maximum length of the papers published so that all experimental results can be reproduced.