{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:40:54Z","timestamp":1760143254765,"version":"build-2065373602"},"reference-count":45,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2024,1,27]],"date-time":"2024-01-27T00:00:00Z","timestamp":1706313600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia (FCT), under LAETA","award":["UIDB\/50022\/2020","CIMPOR\/ADIST 006\/2016","2022.10652.BDANA"],"award-info":[{"award-number":["UIDB\/50022\/2020","CIMPOR\/ADIST 006\/2016","2022.10652.BDANA"]}]},{"name":"CIMPOR SGPS","award":["UIDB\/50022\/2020","CIMPOR\/ADIST 006\/2016","2022.10652.BDANA"],"award-info":[{"award-number":["UIDB\/50022\/2020","CIMPOR\/ADIST 006\/2016","2022.10652.BDANA"]}]},{"name":"FCT","award":["UIDB\/50022\/2020","CIMPOR\/ADIST 006\/2016","2022.10652.BDANA"],"award-info":[{"award-number":["UIDB\/50022\/2020","CIMPOR\/ADIST 006\/2016","2022.10652.BDANA"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"To ensure the acceptable mechanical strength of amorphous wollastonitic hydraulic binders (AWHs), activation with a sodium silicate solution is necessary. However, the use of this type of activator increases the final cost and the complexity of the product\u2019s overall use. In this work, we focus on enhancing the manufacturing of the alkaline activator by producing three Na2SiO3 powders using cost-effective raw materials. The procedure consisted of heating a mixture of NaOH pebbles with either sand, glass, or diatomite to a temperature of 330 \u00b0C for 2 h. After synthesis, the powders were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) techniques. Finally, mortars made with AWHs were activated using the synthesized powders that were added either as a solid or dissolved in an aqueous solution. The compressive strength results in these mortars show that the lab-made activators are competitive with the traditional sodium silicate activators. Furthermore, the synthetized activators can be added in either solid form or pre-dissolved in a solution. This innovative approach represents a more economical, sustainable and easy-to-use approach to enhancing the competitiveness of AWHs.<\/jats:p>","DOI":"10.3390\/ma17030626","type":"journal-article","created":{"date-parts":[[2024,1,30]],"date-time":"2024-01-30T07:49:47Z","timestamp":1706600987000},"page":"626","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["The Use of Solid Sodium Silicate as Activator for an Amorphous Wollastonitic Hydraulic Binder"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6914-4606","authenticated-orcid":false,"given":"M\u00f3nica","family":"Antunes","sequence":"first","affiliation":[{"name":"Intituto Superior T\u00e9cnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"},{"name":"IDMEC\u2014Instituto de Engenharia Mec\u00e2nica, University of Lisbon, 1649-004 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4675-7696","authenticated-orcid":false,"given":"Rodrigo Lino","family":"Santos","sequence":"additional","affiliation":[{"name":"CIMPOR\u2014Cimentos de Portugal, SGPSS.A., Praceta Te\u00f3filo Ara\u00fajo Rato, 2600-540 Alhandra, Portugal"}]},{"given":"Jo\u00e3o","family":"Pereira","sequence":"additional","affiliation":[{"name":"CIMPOR\u2014Cimentos de Portugal, SGPSS.A., Praceta Te\u00f3filo Ara\u00fajo Rato, 2600-540 Alhandra, Portugal"}]},{"given":"Ricardo Bay\u00e3o","family":"Horta","sequence":"additional","affiliation":[{"name":"Intituto Superior T\u00e9cnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5529-1621","authenticated-orcid":false,"given":"Rog\u00e9rio","family":"Cola\u00e7o","sequence":"additional","affiliation":[{"name":"Intituto Superior T\u00e9cnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"},{"name":"IDMEC\u2014Instituto de Engenharia Mec\u00e2nica, University of Lisbon, 1649-004 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1675","DOI":"10.5194\/essd-11-1675-2019","article-title":"Global CO2 Emissions from Cement Production, 1928\u20132018","volume":"11","author":"Andrew","year":"2019","journal-title":"Earth Syst. Sci. Data"},{"key":"ref_2","first-page":"1305","article-title":"Alkali-Activated Binders: A Review. Part 1. Historical Background, Terminology, Reaction Mechanisms and Hydration Products","volume":"22","author":"Jalali","year":"2008","journal-title":"Constr. Build. Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1315","DOI":"10.1016\/j.conbuildmat.2007.03.019","article-title":"Alkali-Activated Binders: A Review. Part 2. About Materials and Binders Manufacture","volume":"22","author":"Jalali","year":"2008","journal-title":"Constr. Build. Mater."},{"key":"ref_4","unstructured":"Provis, J.L., and Rees, C.A. (2009). Geopolymers: Structures, Processing, Properties and Industrial Applications, Woodhead Publishing."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1016\/j.jclepro.2015.12.010","article-title":"Development of Greener Alkali-Activated Cement: Utilisation of Sodium Carbonate for Activating Slag and Fly Ash Mixtures","volume":"113","author":"Abdalqader","year":"2016","journal-title":"J. Clean. Prod."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1617\/s11527-013-0211-5","article-title":"Geopolymers and Other Alkali Activated Materials: Why, How, and What?","volume":"47","author":"Provis","year":"2014","journal-title":"Mater. Struct.\/Materiaux Constr."},{"key":"ref_7","unstructured":"Glukhovsky, V.D. (1981). Slag-Alkali Concretes Produced from Fine-Grained Aggregate, Vishcha Shkola."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1016\/j.cemconres.2013.12.005","article-title":"Use of Glass Waste as an Activator in the Preparation of Alkali-Activated Slag. Mechanical Strength and Paste Characterisation","volume":"57","author":"Puertas","year":"2014","journal-title":"Cem. Concr. Res."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Antunes, M., Santos, R.L., Horta, R.B., and Cola\u00e7o, R. (2023). Novel Amorphous-Wollastonitic Low-Calcium Hydraulic Binders: A State-of-the-Art Review. Materials, 16.","DOI":"10.20944\/preprints202306.1134.v1"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"865","DOI":"10.1016\/S0008-8846(02)00717-2","article-title":"Sodium Silicate-Based, Alkali-Activated Slag Mortars-Part I. Strength, Hydration and Microstructure","volume":"32","author":"Brough","year":"2002","journal-title":"Cem. Concr. Res."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Sasui, S., Kim, G., Nam, J., van Riessen, A., Eu, H., Chansomsak, S., Alam, S.F., and Cho, C.H. (2020). Incorporation of Waste Glass as an Activator in Class-C Fly Ash\/GGBS Based Alkali Activated Material. Materials, 13.","DOI":"10.3390\/ma13173906"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.conbuildmat.2013.01.023","article-title":"Carbon Dioxide Equivalent (CO2-e) Emissions: A Comparison between Geopolymer and OPC Cement Concrete","volume":"43","author":"Turner","year":"2013","journal-title":"Constr. Build. Mater."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"102010","DOI":"10.1016\/j.jobe.2020.102010","article-title":"Ribeiro Application of Eco-Friendly Alternative Activators in Alkali-Activated Materials: A Review","volume":"35","author":"Mendes","year":"2021","journal-title":"J. Build. Eng."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"189","DOI":"10.3151\/jact.21.189","article-title":"A Review of Recent Advances in Alkali-Activated Materials from Silica-Rich Wastes Derived Sodium Silicate Activators","volume":"21","author":"Lin","year":"2023","journal-title":"J. Adv. Concr. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1016\/j.jclepro.2018.08.025","article-title":"Use of Vietnamese Rice Husk Ash for the Production of Sodium Silicate as the Activator for Alkali-Activated Binders","volume":"201","author":"Tong","year":"2018","journal-title":"J. Clean. Prod."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Handayani, L., Aprilia, S., Rahmawati, C., Aulia, T.B., Ludvig, P., and Ahmad, J. (2022). Sodium Silicate from Rice Husk Ash and Their Effects as Geopolymer Cement. Polymers, 14.","DOI":"10.3390\/polym14142920"},{"key":"ref_17","unstructured":"Oktavia, B., Ramadhani, I., and Zainul, R. (2023). Proceedings of the AIP Conference Proceedings, American Institute of Physics Inc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/j.conbuildmat.2016.03.184","article-title":"Geopolymer Binders from Metakaolin Using Sodium Waterglass from Waste Glass and Rice Husk Ash as Alternative Activators: A Comparative Study","volume":"114","author":"Kong","year":"2016","journal-title":"Constr. Build. Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1235","DOI":"10.1111\/ijac.14004","article-title":"Bio-Derived Sodium Silicate for the Manufacture of Alkali-Activated Binders: Use of Bamboo Leaf Ash as Silicate Source","volume":"19","author":"Vinai","year":"2022","journal-title":"Int. J. Appl. Ceram. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"P\u00e9rez-Casas, J.A., Zald\u00edvar-Cadena, A.A., \u00c1lvarez-Mendez, A., Ruiz-Vald\u00e9s, J.J., Parra-Arciniega, S.M.d.l., L\u00f3pez-P\u00e9rez, D.C., and S\u00e1nchez-V\u00e1zquez, A.I. (2023). Sugarcane Bagasse Ash as an Alternative Source of Silicon Dioxide in Sodium Silicate Synthesis. Materials, 16.","DOI":"10.20944\/preprints202306.2233.v1"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"106397","DOI":"10.1016\/j.jobe.2023.106397","article-title":"Sodium-Based Activators in Alkali-Activated Materials: Classification and Comparison","volume":"70","author":"Guo","year":"2023","journal-title":"J. Build. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1077","DOI":"10.1016\/j.conbuildmat.2018.08.096","article-title":"Extensive Reuse of Soda-Lime Waste Glass in Fly Ash-Based Geopolymers","volume":"188","author":"Toniolo","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.cemconres.2018.11.008","article-title":"Production of Sodium Silicate Powder from Waste Glass Cullet for Alkali Activation of Alternative Binders","volume":"116","author":"Vinai","year":"2019","journal-title":"Cem. Concr. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"11708","DOI":"10.1038\/s41598-022-15882-4","article-title":"Comparing Amorphous Silica, Short-Range-Ordered Silicates and Silicic Acid Species by FTIR","volume":"12","author":"Ellerbrock","year":"2022","journal-title":"Sci. Rep."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2209","DOI":"10.1557\/JMR.1990.2209","article-title":"The Infrared Transmission Spectra of Four Silicate Glasses before and after Exposure to Water","volume":"5","author":"Husung","year":"1990","journal-title":"J. Mater. Res."},{"key":"ref_26","unstructured":"Garcia, M.D. (2018). Synthesis by Supercritical Fluids Methods of Advanced Additions for Cementitious Materials. [Ph.D. Thesis, Universit\u00e9 de Bordeaux]."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1007\/s12034-011-0064-x","article-title":"IR and Raman Spectroscopic Studies of Sol-Gel Derived Alkaline-Earth Silicate Glasses","volume":"34","author":"Kalampounias","year":"2011","journal-title":"Bull. Mater. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/1065-7355(94)00031-X","article-title":"Determining Cement Composition by Fourier Transform Infrared Spectroscopy","volume":"2","author":"Hughes","year":"1995","journal-title":"Adv. Ceme. Based Mater."},{"key":"ref_29","first-page":"811","article-title":"FTIR Quantitative Analysis of Calcium Carbonate (Calcite) and Silica (Quartz) Mixtures Using the Constant Ratio Method. Application to Geological Samples","volume":"16","author":"Adelantado","year":"2002","journal-title":"Talanta"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4158","DOI":"10.1111\/jace.15554","article-title":"Alkali Activation of a Novel Calcium-Silicate Hydraulic Binder","volume":"101","author":"Santos","year":"2018","journal-title":"Am. Ceram. Soc."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"525","DOI":"10.1007\/s40996-019-00336-1","article-title":"Geopolymer Synthesis with Low Sodium Hydroxide Concentration","volume":"44","author":"Arioz","year":"2020","journal-title":"Iranian J. Sci. Technol.\u2014Trans. Civil. Eng."},{"key":"ref_32","unstructured":"Madavarapu, S.B., Neithalath, N., Rajan, S., and Marzke, R. (2014). FTIR Analysis of Alkali Activated Slag and Fly Ash Using Deconvolution Techniques, Arizona State University."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"13135","DOI":"10.1039\/C9CP01306G","article-title":"Alkali Carbonates Promote CO2 Capture by Sodium Orthosilicate","volume":"21","author":"Liu","year":"2019","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"651","DOI":"10.1016\/j.cemconres.2011.03.026","article-title":"Hydration of Cementitious Materials, Present and Future","volume":"41","author":"Scrivener","year":"2011","journal-title":"Cem. Concr. Res."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1016\/j.cemconres.2018.08.005","article-title":"The Needle Model: A New Model for the Main Hydration Peak of Alite","volume":"115","author":"Ouzia","year":"2019","journal-title":"Cem. Concr. Res."},{"key":"ref_36","first-page":"300","article-title":"Assessment of the Performance of Alkali-Activated Slag\/Fly Ash Using Liquid and Solid Activators: Early-Age Properties and Efflorescence","volume":"13","author":"Gong","year":"2023","journal-title":"J. Sustain. Cem. Based Mater."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"903","DOI":"10.1107\/S2052520614021982","article-title":"Model Structures for C-(A)-S-H(I)","volume":"70","author":"Richardson","year":"2014","journal-title":"Acta Crystallogr. B Struct. Sci. Cryst. Eng. Mater."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"4960","DOI":"10.1038\/ncomms5960","article-title":"Combinatorial Molecular Optimization of Cement Hydrates","volume":"5","author":"Krakowiak","year":"2014","journal-title":"Nat. Commun."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.cemconres.2016.03.006","article-title":"Novel High-Resistance Clinkers with 1.10