Use of Vietnamese rice husk ash for the production of sodium silicate as the activator for alkali-activated binders

By Kien Ton Tong, R. Vinai, M. Soutsos. Journal of Cleaner Production, 2018

229 citations recorded by the source corpus.

Abstract Geopolymer and Alkali-Activated Binders (AAB) has recently emerged as a new, green material with the potential to replace Portland cement in several applications. They can reduce the CO2 footprint of concrete by up to 80% and this is in addition to being more durable in certain aggressive environments. However, commercial alkaline activators contribute significantly to the cost and CO2 footprint of AAB concrete mixes. This research investigated the production of a low cost, low environmental impact sodium silicate solution (waterglass) from Rice Husk Ash (RHA) and more specifically RHA from Vietnam. A hydrothermal process for the dissolution of RHA in sodium hydroxide solution was developed. Sodium hydroxide solution concentration, process temperature and duration were studied. Optimised procedure parameters were found to be: NaOH concentration 3M, heating temperature 80 °C and heating duration 3 h. The obtained solution was used for the production of AAB mortar made with a blend of fly ash and ground granulated blast furnace slag. Obtained compressive strength of mortar was in the range of 60 MPa at 28 days, matching the strength obtained from control samples produced with commercially available activators. Microstructural investigation (isothermal calorimetry, infrared spectroscopy, X-ray diffraction and thermogravimetric analysis) on pastes confirmed the equivalence between the solution produced with the optimised method and commercially available options. Cost analysis indicated that the proposed method could allow a reduction of almost 55% of the cost for the activation of AAB. Results from a simplified preliminary environmental analysis suggested increased sustainability of the RHA-derived solution when compared with commercially available waterglass.

Subfields: Building and Construction, Civil and Structural Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/997cfcfe674b639c5bd308722097e54c10a8b177

How researchers see this paper

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In Building and Construction

1. Mariam Abdulkareem
2. Jouni Havukainen
3. J. Nuortila‐Jokinen
4. Mika Horttanainen

In Civil and Structural Engineering

1. Mariam Abdulkareem
2. Jouni Havukainen
3. J. Nuortila‐Jokinen
4. Mika Horttanainen

In Materials Chemistry

1. Mariam Abdulkareem
2. Jouni Havukainen
3. J. Nuortila‐Jokinen
4. Mika Horttanainen

Citations in the corpus

• Environmental and economic perspective of waste-derived activators on alkali-activated mortars (2021, methodology): “By and large, AABs are produced by reacting solid aluminosilicate raw materials (precursor) with an alkaliactivator to form a hardened binder (Tong et al., 2018; Vinai and Soutsos, 2019).”
• Production of sodium silicate powder from waste glass cullet for alkali activation of alternative binders (2019, unknown): “A literature analysis of hydrothermal methods for the extraction of silicate from waste in aqueous alkali solutions was detailed in a previous study [18].”