Effect of washing aggregate sludge waste on the properties of alkali-activated blast furnace slag

Bilici, Senem; Kabay, Nihat; Miyan, Nausad; Ömür, Tarık; Özkan, Hakan

doi:10.1016/j.jobe.2022.105527

Cited by 3 publications

(1 citation statement)

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“…Blast furnace slag is often combined with other co-products (waste) for the manufacture of alkali-activated materials, such as fly ash [27], washing aggregate sludge [29]; boron waste [30]; sludge waste [31,32]. Slags of specific compositions (Fe-rich fayalite slag (FS), ferronickel slag (FNS)) have also been the subject of investigations with the aim of developing alkali-activated materials [33,34].…”

Section: Introductionmentioning

confidence: 99%

Valorization of a Steel Industrial Co-Product for the Development of Alkali-Activated Materials: Effect of Curing Environments

Sarri

Oualit

Kennouche

2023

Advances in Materials Science

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While natural resources are becoming scarce and climate change is accelerating, the recovery and recycling of wastes and by-products is an effective way to deal with the economic and ecological constraints of recent decades. The valorization of industrial by-products in civil engineering is a common practice either by their incorporation during the manufacture of Portland cements or as a partial replacement of cement during the production of concrete. The present work aims to develop waste-based alkali-activated materials WAAMs intended for civil engineering applications as a potential alternative to cement-based materials. A steel industrial by-product called commonly granulated blast furnace slag GBFS was used alone as a solid CaO-rich precursor; two alkaline activators such us sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) were used separately for the production of two-part alkali-activated materials. Besides the microstructure analysis of the hardened samples, the influence of activator/precursor mass ratio, NaOH molarity, and two curing environments (Room temperature and 60°C) on the compressive strength, water accessible porosity, mass loss, and drying shrinkage were assessed. The results showed that a high Liquid/Solid ratio leads to a decrease in the compressive strength of the samples, while high NaOH molarity significantly improves the mechanical properties by reducing the porosity of the specimens. Moreover, alkaline silicate activator provides higher compressive strengths compared to the alkaline hydroxide activator, especially when the samples were cured at room temperature where a maximum 28days-compressive strength value of 105.28 MPa was achieved. For the samples activated using sodium hydroxide solution, the results revealed that their curing at 60°C promotes obtaining high initial-compressive strengths (7 days) before decreasing subsequently as a function of the curing time. As an indication, at high alkaline concentration (NaOH = 9M), a mechanical strength decline of 21% was recorded between a curing time of 7 to 28 days. Moreover, curing at 60°C induced high porosity, significant mass loss and high drying shrinkage. SEM analysis highlighted a dense, homogeneous microstructure without apparent defects, in particular for the samples where the alkali silicate activator was used.

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Section: Introductionmentioning

confidence: 99%

Valorization of a Steel Industrial Co-Product for the Development of Alkali-Activated Materials: Effect of Curing Environments

Sarri

Oualit

Kennouche

2023

Advances in Materials Science

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Innovative use of hazelnut shell ash as an alkali activator: A comparative analysis with commercial activators

Omur,

Kanat,

Kabay

2024

Journal of Building Engineering

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Compressive Strength and Microstructure of Carbide Slag and Alkali-Activated Blast Furnace Slag Pastes in China

Li,

Xu,

Sun

et al. 2024

Buildings

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The alkali-activated blast furnace slag is attracting significant attention in replacing Portland cement due to several characteristics similar to cement hydration. However, there are a few practical problems with commercial alkali activators, such as the fast setting time, relatively high costs, and significant CO2 emissions during preparation. Thus, discovering industrial residues possessing inherent alkalinity are urgent. This study proposes the use of carbide slag at levels of 0%, 5%, 10%, 15%, 20%, and 30% and alkali at levels of 1%, 2%, 3%, 4%, 5%, 6%, 8%, and 10% activated blast furnace slag. The compressive strength and microstructure of carbide slag and alkali-activated blast furnace slag (CAB) pastes were examined using X-ray diffraction analysis (XRD), Differential Scanning Calorimetry/Thermogravimetric Analysis (DSC/TG), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The results revealed that the addition of carbide slag produced more hydrotalcite-like phase as well as decreased the content of ettringite (AFt) and the calcium–silicate–hydrate (C-S-H) gel, which decreased the compressive strength of the CAB pastes. At the age of 28 days, when the dosage was 5%, 10%, 15%, 20%, and 30%, the compressive strength of CAB mixes decreased by 2.1%, 7.1%, 9.2%, 9.8%, and 28.1%, respectively. The addition of NaOH promoted the formation of AFt, and there was an optimum level of NaOH corresponding to the high compressive strength of paste. At the age of 3 days and 7 days, the compressive strength reached its maximum at the dosage of 6% NaOH, which was 24.8 MPa and 36.3 MPa, respectively. However, at the ages of 14 days and 28 days, the compressive strength increased as the dosage of NaOH increased to 5%, which was 43.3 MPa and 44.5 MPa, respectively. The water curing could both enhance the early and later strength, the compressive strength of 23.3 MPa was gained at 3 days, and this increased by 16.3%, 24.0% and 36.9% at 7 days, 14 days and 28 days, respectively. Therefore, water curing was suitable for the strength development of CAB pastes.

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Effect of washing aggregate sludge waste on the properties of alkali-activated blast furnace slag

Cited by 3 publications

References 73 publications

Valorization of a Steel Industrial Co-Product for the Development of Alkali-Activated Materials: Effect of Curing Environments

Valorization of a Steel Industrial Co-Product for the Development of Alkali-Activated Materials: Effect of Curing Environments

Innovative use of hazelnut shell ash as an alkali activator: A comparative analysis with commercial activators

Compressive Strength and Microstructure of Carbide Slag and Alkali-Activated Blast Furnace Slag Pastes in China

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