Use of water treatment sludge in Self-Compacting Mortar (SCM)

Ana Paula Teixeira Da Silva,Mírian De Lourdes Noronha Motta Melo,Valquíria Claret Dos Santos,Marcia Viana Lisboa Martins,Vander Alkmin Dos Santos Ribeiro,Lucas Ramon Roque Da Silva,Michel Henry Bacelar De Souza,Paulo Cesar Gonçalves

doi:10.33448/rsd-v11i2.25112

Ana Paula Teixeira Da Silva, Mírian De Lourdes Noronha Motta Melo + Show 6 more

Open Access

https://doi.org/10.33448/rsd-v11i2.25112

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Abstract

This paper aims to analyze the characteristics of self-compacting mortar (SCM) with the partial replacement of cement by water treatment sludge (WTS). This replacement aims to contribute to minimize environmental degradation arising from the production of materials used in construction and to give a sustainable destination to the sludge generated in water treatment plants. In this study, the substitution of cement in 10 and 20% for the WTS from the Itajubá Water Treatment Plant in Minas Gerais was analyzed. The residue was collected, filtered, dried and ground, so that the granulometric analyses could be performed and the data inserted in the EMMA particle packing software. Regarding the mortar, the properties in the fresh state were verified through the spreading and flow tests, in which all mixtures could be defined as self-compacting. Regarding the mechanical properties, compression, flexural tensile and modulus of elasticity tests were performed after 28 days of curing. In the mixtures containing WTS, the mechanical strengths and modulus of elasticity decreased. Furthermore, in the hardened state, a reduction in specific mass and an increase in the voids index and absorption was observed in the traces containing WTS. The results indicate that WTS could be used only for non-structural function. However, the results obtained reinforce the need for further studies on the subject, maintaining the possibility of using the WTS in civil construction.

Highlights

Idealized as the revolutionary advance of conventional concrete, whose particular characteristic is self-compaction in the molds without the need for mechanical vibration, self-compacting concrete (SCC) was originally developed to compensate for a growing shortage of skilled labor (Okamura & Ouchi, 2003)
Tests of reference concrete and concrete with addition of dried sludge in the fresh state and in the hardened state were performed and the results showed that the slump values, in general, were higher than those obtained in the reference concrete and the compressive strength tests, all specimens with addition of dried sludge from Andesita showed a reduction of values when compared to the reference concrete
In light of the above, this study aims to analyze the replacement of cement in 10 and 20% by water treatment sludge (WTS) in the production of mortar, in order to reduce the impact of the extraction of materials for construction and give an appropriate destination for the sludge generated in the water treatment plant of Itajubá Minas Gerais

Summary

Introduction

Idealized as the revolutionary advance of conventional concrete, whose particular characteristic is self-compaction in the molds without the need for mechanical vibration, self-compacting concrete (SCC) was originally developed to compensate for a growing shortage of skilled labor (Okamura & Ouchi, 2003). The main property that differs SCC from conventional concrete is its full compaction capacity even in structures with high reinforcement density or narrow sections and this property is governed by the high fluidity and cohesion mechanisms of the mixture (Dinakar, 2012). Another important property of SCC is the stability and resistance to segregation ensuring the viscosity of the paste and mortar, components of SCC. An alternative to the high consumption of cement as a fine material in the production of SCC is the addition of minerals that contribute to selfcompacting, resistance to segregation, viscosity and improves workability in the fresh state

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