Structural analysis and mechanical behavior of cement mortars with valorization by drinking water treatment sludge as partial replacement

Leila Djekoune, Aziz Maaliou, Dalila Ziani, Abderzak Moussoun

https://doi.org/10.5004/ic202419

Structural analysis and mechanical behavior of cement mortars with valorization by drinking water treatment sludge as partial replacement

Leila Djekoune¹, Aziz Maaliou², Dalila Ziani², Abderzak Moussouni³

¹ University of Science and Technology Houari Boumediene, Faculty of Mechanical and Process Engineering, Laboratory of Sciences and Industrial Process Engineering (LSGPI), PB 32 El-Alia, Bab - Ezzouar, 16311, Algiers, Algeria
² University of Science and Technology Houari Boumediene, Faculty of Civil Engineering, LEGHYD Laboratory, PB 32 El-Alia, Bab - Ezzouar, 16311, Algiers, Algeria
³ University Center of Mila, LEGHYD Laboratory, POBox N°26 RP Mila 43000, Algeria

https://doi.org/10.5004/ic202419

ABSTRACT

The generation of sludge is a byproduct of drinking water production. This study explores using alum sludge (AS) in construction materials as a substitute for cement in proportions of 5%, 10%, 15%, 20%, and 25%. Although alum sludge is not a natural pozzolan based on its chemical composition, it can be classified as a Class N pozzolanic material, making it suitable for replacing cement in concrete. Experimental results show that a 5% substitution is the optimal rate for replacing cement with sludge. XRD and SEM-EDS analyses of the alum sludge-cement mortars identified the formation of hydrated compounds like portlandite (Ca(OH)₂) and calcium silicate hydrate (C-S-H). After 28 d of curing, all sludge mortars achieved compressive strengths that meet the standards for building materials.

Keywords: Reuse; Alum sludge; Mortars; Construction materials; Compressive strength

Abstract