Influence of replacing Portland cement with three different concrete sludge wastes

• Published in: Construction & building materials 2021-10, Vol.303, p.124519, Article 124519
• Main Authors: Martins, Juliana Vieira, Garcia, Dayana Cristina Silva, Aguilar, Maria Teresa Paulino, dos Santos, White José
• Format: Article
• Language: English
• Subjects: Cement with addition of residue; Characteristics of concrete sludge waste; Filler; Ready-mixed concrete plant sludge
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.124519

•Influence of characteristics of concrete sludge waste on the performance of Portland cement composites.•Results of replacement of cement by concrete sludge waste on fresh state properties, mechanical properties, and durability.•Technical feasibility of using concrete sludge waste in non-structural cementitious composites. Ready-mixed concrete manufacturing consumes a lot of cement and generates millions of m3 of concrete sludge waste (CSW). It is known that CSW is heterogeneous and has different chemical and physical properties. This paper evaluates the influence of fine CSW fractions on the properties of structural mortars by partially replacing cement with fine fractions of concrete sludge waste. CSW samples were collected from three different concrete batching plants (CBPs) and 25% of cement used in concrete production was replaced by fine fractions of sludge – maintaining the water/fines ratio and no additives were used. The results showed that the variation in characteristics of the three CSWs influenced the properties of the mortars produced. Results at hardened state, with cement replacement by fine sludge waste, were close to those recorded for mortars composed with the addition of limestone filler – values were within the ranges set by the standard for composite cement with filler. The results became closer as calcite content increased in the sludge samples.