Characterization of Glass Powder from Glass Recycling Process Waste and Preliminary Testing

[EN] This work studies the possibility of incorporating different proportions of glass powder from the waste glass (rejected material called fine cullet) produced during the glass recycling process into the manufacturing of mortar and concrete. For this purpose, the material is characterized by its chemical composition and pozzolanic activity, and the shape and size of its particles are studied. It is then incorporated as a substitute for cement into the manufacturing of mortar and concrete at 25% and 40% of cement weight, and its effect on setting times, consistency, and mechanical strength is analyzed. Its behavior as a slow pozzolan is verified, and the possibility of incorporating it into concrete is ratified by reducing its cement content and making it a more sustainable material.This research was funded by Agencia Valenciana de la Innovacio (AVI) grant number INNEST/2020/85.Gimenez-Carbo, E.; Soriano Martinez, L.; Roig-Flores, M.; Serna Ros, P. (2021). Characterization of Glass Powder from Glass Recycling Process Waste and Preliminary Testing. Materials. 14(11):1-15. https://doi.org/10.3390/ma14112971S115141

Influence of microwave oven calcination on the pozzolanicity of sugar cane bagasse ashes (SCBA) from the cogeneration industry

[EN] This study evaluates the effects of microwave oven calcining conditions on the pozzolanicity of sugar cane bagasse ashes (SCBA) generated by the electric power cogeneration industry. The calcining temperatures varied between 600 ºC and 800 ºC, and the permanence times were 60 min in an electric oven and 30, 45 and 60 min in a microwave oven. To evaluate the behaviour of the ashes according to different calcining conditions, we carried out the following analyses: granulometric distribution (laser diffraction), oxide percentages (XRF), loss on ignition (LOI), powder X-ray diffraction (XRD), pozzolanic reactivity, determination of amorphous silica content and thermogravimetry of hydrated lime pastes (DTG). The results show that SCBA calcination in a microwave oven results in ashes with greater pozzolanic reactivity and a significantly more efficient burning process than in an electric oven.The authors would like to thank the CNPq-Brazil (Project: 200133/2017-9) for financial support.Rossignolo, J.; Borrachero Rosado, MV.; Soriano Martinez, L.; Paya Bernabeu, JJ. (2018). Influence of microwave oven calcination on the pozzolanicity of sugar cane bagasse ashes (SCBA) from the cogeneration industry. Construction and Building Materials. 187:892-902. https://doi.org/10.1016/j.conbuildmat.2018.08.016S89290218

Air-void system characterization of new eco- cellular concretes

[EN] Cellular concrete is an alternative to conventional concrete as a low-density and high-insulating building material. The eco-cellular concretes (ECCs) based on geopolymer technology have been recently introduced by the scientific community. A form of ECC was studied, in which the fluid catalytic cracking residue and the blast furnace slag were employed as precursors, the rice husk ash was utilized as an alternative silica source in the activator, and the aerating reagent was replaced with recycled aluminum foil. Field emission scanning electron microscopy, optical microscopy, and ImageJ version 1.48 software (National Institutes of Health) were employed to characterize the void distribution. Bulk density and porosity were determined by hydric tests. The results revealed that lowest densities without strength loss were obtained when the cementing matrix had a homogeneous void system: similar spacing between pores, narrow size ranges, and nonconnected pores. A relationship was established between open and closed porosity with density and thermal conductivity.The authors acknowledge the financial support from the Universitat Politecnica de Valencia (UPV) through internal project GEOCELPLUS. The authors are especially grateful to Dr. Josefa L. Rosello Caselles for the recycled aluminum foil, and also to the Electronic Microscopy Service of the UPV. Thanks also go to DACSA, BP Oil, and Cementval for supplying the raw materials.Font-Pérez, A.; Borrachero Rosado, MV.; Soriano Martinez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ. (2021). Air-void system characterization of new eco- cellular concretes. Journal of Materials in Civil Engineering. 33(5):1-10. https://doi.org/10.1061/(ASCE)MT.1943-5533.0003692S11033

Stabilization of soil by means alternative alkali-activated cement prepared with spent FCC catalyst

[EN] Alkali-activated cements are widely studied as alternative and sustainable binder in soil stabilization. In this research work, a mold was designed and constructed, which allowed small cubic specimens to be made (40 x 40 x 40 mm(3)). With the newly designed mold, cubic samples of soil stabilized with portland cement (OPC) and alternative AAC (based on spent fluid catalytic cracking catalyst FCC) were prepared from which compressive strength was obtained. Cylindrical specimens were also prepared using the same binders as in the previous case to obtain their compressive strength. The results obtained in both cases were compared. Greater resistances for cubic samples were achieved. The cubic specimens were selected for being better in terms of standard deviation of compressive strength for AAC stabilized soil. The obtained compressive strength and standard deviation results were compared between the soil specimens stabilized with different stabilizers cured at 7, 14, 28, and 90 days. The method allows small-sized cubic specimens to be prepared. It improves ergonomics. It also facilitates a large number of specimens being obtained with a small amount of sample. Soil stabilized with AAC yielded higher compressive strength after 90 days compared to that with OPC.Spanish Ministry of Economy and Competitiveness, Grant/Award Number: BIA2015 70107-R.Cosa-Martínez, J.; Soriano Martinez, L.; Borrachero Rosado, MV.; Paya Bernabeu, JJ.; Monzó Balbuena, JM. (2020). Stabilization of soil by means alternative alkali-activated cement prepared with spent FCC catalyst. International Journal of Applied Ceramic Technology. 17(1):190-196. https://doi.org/10.1111/ijac.13377S190196171UNE‐EN 12390‐1.Testing hardened concrete ‐ Part 1: Shape dimensions and other requirements for specimens and moulds.2013.UNE‐EN 41410.Compressed earth blocs for walls and partitions. Definitions specifications and test Methods.2008.ASTM D‐18C. ed. STP479‐EB Special Procedures for Testing Soil and Rock for Engineering Purposes: 5th ed. West Conshohocken PA: ASTM International.1970.https://doi.org/10.1520/STP479-EBUNE‐EN 196–1.Methods of testing cement ‐ Part 1: Determination of strength.2005.Auroville Earth Institute Earthen architecture for sustainable habitat and compressed stabilized earth block technology [cited 2019 Sep 2]. Available fromhttp://www.ada.gov.sa/idc/groups/public/documents/AR_ADA_Researches/004568.pdfNLT‐310 90.Vibrating hammer compaction of treated granular. materials.1990.UNE‐EN 13286‐2.Unbound and hydraulically bound mixtures ‐ Part 2: Test methods for laboratory reference density and water content ‐. Proctor compaction.2011.Khadka, B., & Shakya, M. (2015). Comparative compressive strength of stabilized and un-stabilized rammed earth. Materials and Structures, 49(9), 3945-3955. doi:10.1617/s11527-015-0765-5Alrubaye, A. J., Hasan, M., & Fattah, M. Y. (2016). Stabilization of soft kaolin clay with silica fume and lime. International Journal of Geotechnical Engineering, 11(1), 90-96. doi:10.1080/19386362.2016.1187884Zhang, M., Guo, H., El-Korchi, T., Zhang, G., & Tao, M. (2013). Experimental feasibility study of geopolymer as the next-generation soil stabilizer. Construction and Building Materials, 47, 1468-1478. doi:10.1016/j.conbuildmat.2013.06.017Zhang, M., Zhao, M., Zhang, G., Nowak, P., Coen, A., & Tao, M. (2015). Calcium-free geopolymer as a stabilizer for sulfate-rich soils. Applied Clay Science, 108, 199-207. doi:10.1016/j.clay.2015.02.029Bouzón, N., Payá, J., Borrachero, M. V., Soriano, L., Tashima, M. M., & Monzó, J. (2014). Refluxed rice husk ash/NaOH suspension for preparing alkali activated binders. Materials Letters, 115, 72-74. doi:10.1016/j.matlet.2013.10.001Mejía, J. M., Mejía de Gutiérrez, R., & Montes, C. (2016). Rice husk ash and spent diatomaceous earth as a source of silica to fabricate a geopolymeric binary binder. Journal of Cleaner Production, 118, 133-139. doi:10.1016/j.jclepro.2016.01.057Puertas, F., & Torres-Carrasco, M. (2014). Use of glass waste as an activator in the preparation of alkali-activated slag. Mechanical strength and paste characterisation. Cement and Concrete Research, 57, 95-104. doi:10.1016/j.cemconres.2013.12.005CosaJ SorianoL BorracheroMV PayáJ MonzóJ.Use ofAlkaline Activated Cements from Residues for Soil Stabilization. NOCMAT 2017. Proceeding Paper Published. In: Ghavami K Herrera PJ eds. Materials Research Proceedings. 2018. 7:257–64.http://dx.doi.org/10.21741/9781945291838-23Tashima, M. M., Akasaki, J. L., Castaldelli, V. N., Soriano, L., Monzó, J., Payá, J., & Borrachero, M. V. (2012). New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC). Materials Letters, 80, 50-52. doi:10.1016/j.matlet.2012.04.051Mellado, A., Catalán, C., Bouzón, N., Borrachero, M. V., Monzó, J. M., & Payá, J. (2014). Carbon footprint of geopolymeric mortar: study of the contribution of the alkaline activating solution and assessment of an alternative route. RSC Adv., 4(45), 23846-23852. doi:10.1039/c4ra03375bUNE‐EN 103 501.Geotechnics. Compactation test. Modified proctor.1994.ASTMD1557–12e1 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56 000 ft‐lbf/ft3 (2 700 kN‐m/m3)).West Conshohocken PA:ASTM. International.2012.https://doi.org/10.1520/D1557-12E01UNE‐EN 772–1.Methods of test for masonry units.2011.UNE‐EN 197–1.Cement ‐ Part 1: composition specifications and conformity criteria for common cements.2011

Evaluation of rice straw ash as a pozzolanic addition in cementitious mixtures

[EN] Rice husk ash is one of the most widely studied biomass ashes used in pozzolanic addition. Given its lower silica content, rice straw ash (RSA) has been explored less often, despite the fact that, according to the United Nations Food and Agriculture Organization (FAO), rice straw (RS) production is estimated at 600 million tons/year. In this work, RSA was physically and chemically characterized, and its pozzolanic properties were assessed. A controlled conditioning, burning, homogenization and grinding procedure was carried out to obtain RSA from RS. Chemical composition, insoluble residue, reactive silica, chloride content and particle size distribution were assessed for ash characterization. To determine RSA pozzolanicity, Frattini, electrical conductivity and pH measurements in an aqueous suspension of hydrated CH/RSA mixtures were obtained. Portland cement (PC) mortars with 15% and 30% RSA substitutions evaluated. The mechanical tests showed specimens with a strength activity index up to 90% and 80% with 15% and 30% RSA, respectively, after 3 days, and these values grew to 107¿109% after 90 curing daysThis research was funded by the Spanish Government and FEDER funds (MINECO/FEDER-Project RTI2018-09612-B-C21).Hidalgo, S.; Soriano Martinez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Font, A.; Borrachero Rosado, MV. (2021). Evaluation of rice straw ash as a pozzolanic addition in cementitious mixtures. Applied Sciences. 11(2):1-17. https://doi.org/10.3390/app11020773S11711

Production of bamboo leaf ash by auto-combustion for pozzolanic and sustainable use in cementitious matrices

[EN] In the context of world concern with the environment, this study aims to characterize an auto combustion produced bamboo leaf ash (BLA) by its pozzolanic behaviour, reactivity and its influence in the total porosity, pore size distribution, tortuosity and mechanical behaviour of cementitious matrices. The chemical and physical characterization of the BLA was carried using X-ray fluorescence, determination of amorphous silica content, X-ray diffraction, Fourier Transform Infrared Spectrophotometry (FTIR), laser granulometry and field emission scanning electron microscopy (FESEM). The assessed BLA is a siliceous material (74.23%) with an amorphous nature due to the amorphous silica content, which represents 92.33% of the total silica. The BLA was classified as highly reactive by assessing its pH and conductivity in a saturated calcium hydroxide (CH) medium for different proportions and temperatures. Frattini analysis, the study of CH:BLA pastes (Thermogravimetric analysis and FTIR) and Portland cement (OPC)/pozzolan pastes (Thermogravimetric analysis and FESEM) are in agreement with this classification. The replacement of OPC by BLA improved the mechanical behaviour of the cementitious matrices, as well their durability. All the mortars containing BLA presented very similar compressive strength to a control mortar (100% OPC) after only 3 days of curing and at the following tested curing ages: 7, 28 and 90 days. In the mercury intrusion porosimetry analysis, the pastes with 20 and 30% BLA content presented higher tortuosity or fewer connected pores than the control paste. Thus, the auto-combustion method proved to be successful and BLA is a suitable alternative for sustainable high-performance matrices. (C) 2019 Elsevier Ltd. All rights reserved.The authors would like to thank São Paulo Research Foundation (FAPESP), grant #2016/16403-5 and #2017/21563-4.Moraes, M.; Moraes, J.; Tashima, M.; Akasaki, J.; Soriano Martinez, L.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2019). Production of bamboo leaf ash by auto-combustion for pozzolanic and sustainable use in cementitious matrices. Construction and Building Materials. 208:369-380. https://doi.org/10.1016/j.conbuildmat.2019.03.007S36938020

Reuse of industrial and agricultural waste in the fabrication of geopolymeric binders: mechanical and microstructural behavior

[EN] Resource recovery from waste is one of the most important ways to implement the socalled circular economy, and the use of alkali activated materials can become an alternative for traditional PC-based materials. These types of materials are based on waste resources involving a lower carbon footprint and present similar or high properties and good durability compared to that Portland cement (PC). This research work proposes using new waste generated in different types of industries. Four waste types were employed: fluid catalytic cracking residue (FCC) from the petrochemical industry; ceramic sanitary ware (CSW) from the construction industry; rice husk ash (RHA); diatomaceous waste from beer filtration (DB) (food industry). FCC and CSW were employed as precursor materials, and mixtures of both showed good properties of the obtained alkali activated materials generated with commercial products as activators (NaOH/waterglass). RHA and DB were herein used as an alternative silica source to prepare the alkaline activating solution. Mechanical behavior was studied by the compressive strength development of mortars. The corresponding pastes were characterized by X-ray diffraction, thermogravimetric analysis, and microscopy studies. The results were satisfactory, and demonstrated that employing these alternative activators from waste produces alkali activated materials with good mechanical properties, which were sometimes similar or even better than those obtained with commercial reagents.This research was funded by the Spanish Government and FEDER funds (MINECO/FEDERProject RTI2018-09612-B-C21). This research work forms part of a project supported by MINECO and FEDER funds (ECOSOST RTI2018-097612-B-C21).Paya Bernabeu, JJ.; Soriano Martinez, L.; Font, A.; Borrachero Rosado, MV.; Nande, JA.; Monzó Balbuena, JM. (2021). Reuse of industrial and agricultural waste in the fabrication of geopolymeric binders: mechanical and microstructural behavior. Materials. 14(9):1-13. https://doi.org/10.3390/ma1409208911314

Sustainable soil-compacted blocks containing blast furnace slag (BFS) activated with olive stone biomass ash (OBA)

[EN] Soil stabilization using cementing materials is a well-known procedure for earth-based building blocks preparation. For the selected binding materials, innovation usually focuses on low carbon systems, many of which are based on alkaline activation. In the present paper, blast furnace slag (BFS) is used as a mineral precursor, and the innovative alkali activator was olive stone biomass ash (OBA). This means that the most important component in CO2 emissions terms, which is the alkali activator, has been replaced with a greener alternative: OBA. The OBA/BFS mixture was used to prepare compacted dolomitic soil blocks. These specimens were mechanically characterized by compression, and water strength coefficient and water absorption were assessed. The microstructure of blocks and the formation of cementing hydrates were analyzed by field emission scanning electron microscopy and thermogravimetry, respectively. The final compressive strength of the 120-day cured blocks was 27.8 MPa. It was concluded that OBA is a sustainable alkali activator alternative for producing BFS-stabilized soil-compacted blocks: CO2 emissions were 3.3 kgCO(2)/ton of stabilized soil, which is 96% less than that for ordinary Portland cement (OPC) stabilization.This research was funded by the Spanish Government and FEDER funds (MINECO/FEDER-Project RTI2018-09612-B-C21).Paya Bernabeu, JJ.; Monzó Balbuena, JM.; Rosello Caselles, J.; Borrachero Rosado, MV.; Font-Pérez, A.; Soriano Martinez, L. (2020). Sustainable soil-compacted blocks containing blast furnace slag (BFS) activated with olive stone biomass ash (OBA). Sustainability. 12(23):1-14. https://doi.org/10.3390/su12239824S1141223Van Damme, H., & Houben, H. (2018). Earth concrete. Stabilization revisited. Cement and Concrete Research, 114, 90-102. doi:10.1016/j.cemconres.2017.02.035Menchaca-Ballinas, L. E., & Escalante-Garcia, J. I. (2019). Low CO2 emission cements of waste glass activated by CaO and NaOH. Journal of Cleaner Production, 239, 117992. doi:10.1016/j.jclepro.2019.117992Basha, E. A., Hashim, R., Mahmud, H. B., & Muntohar, A. S. (2005). Stabilization of residual soil with rice husk ash and cement. Construction and Building Materials, 19(6), 448-453. doi:10.1016/j.conbuildmat.2004.08.001Rahgozar, M. A., Saberian, M., & Li, J. (2018). Soil stabilization with non-conventional eco-friendly agricultural waste materials: An experimental study. Transportation Geotechnics, 14, 52-60. doi:10.1016/j.trgeo.2017.09.004Sisol, M., Kudelas, D., Marcin, M., Holub, T., & Varga, P. (2019). Statistical Evaluation of Mechanical Properties of Slag Based Alkali-Activated Material. Sustainability, 11(21), 5935. doi:10.3390/su11215935Mellado, A., Catalán, C., Bouzón, N., Borrachero, M. V., Monzó, J. M., & Payá, J. (2014). Carbon footprint of geopolymeric mortar: study of the contribution of the alkaline activating solution and assessment of an alternative route. RSC Adv., 4(45), 23846-23852. doi:10.1039/c4ra03375bTchakouté, H. K., Rüscher, C. H., Kong, S., & Ranjbar, N. (2016). Synthesis of sodium waterglass from white rice husk ash as an activator to produce metakaolin-based geopolymer cements. Journal of Building Engineering, 6, 252-261. doi:10.1016/j.jobe.2016.04.007Tchakouté, H. K., Rüscher, C. H., Hinsch, M., Djobo, J. N. Y., Kamseu, E., & Leonelli, C. (2017). Utilization of sodium waterglass from sugar cane bagasse ash as a new alternative hardener for producing metakaolin-based geopolymer cement. Geochemistry, 77(2), 257-266. doi:10.1016/j.chemer.2017.04.003Moraes, J. C. B., Font, A., Soriano, L., Akasaki, J. L., Tashima, M. M., Monzó, J., … Payá, J. (2018). New use of sugar cane straw ash in alkali-activated materials: A silica source for the preparation of the alkaline activator. Construction and Building Materials, 171, 611-621. doi:10.1016/j.conbuildmat.2018.03.230Font, A., Soriano, L., Reig, L., Tashima, M. M., Borrachero, M. V., Monzó, J., & Payá, J. (2018). Use of residual diatomaceous earth as a silica source in geopolymer production. Materials Letters, 223, 10-13. doi:10.1016/j.matlet.2018.04.010Samarakoon, M. H., Ranjith, P. G., Duan, W. H., & De Silva, V. R. S. (2020). Properties of one-part fly ash/slag-based binders activated by thermally-treated waste glass/NaOH blends: A comparative study. Cement and Concrete Composites, 112, 103679. doi:10.1016/j.cemconcomp.2020.103679Zhao, X., Liu, C., Wang, L., Zuo, L., Zhu, Q., & Ma, W. (2019). Physical and mechanical properties and micro characteristics of fly ash-based geopolymers incorporating soda residue. Cement and Concrete Composites, 98, 125-136. doi:10.1016/j.cemconcomp.2019.02.009Bilginer, A., Canbek, O., & Turhan Erdoğan, S. (2020). Activation of Blast Furnace Slag with Soda Production Waste. Journal of Materials in Civil Engineering, 32(1), 04019316. doi:10.1061/(asce)mt.1943-5533.0002987Ban, C. C., Ken, P. W., & Ramli, M. (2017). Mechanical and Durability Performance of Novel Self-activating Geopolymer Mortars. Procedia Engineering, 171, 564-571. doi:10.1016/j.proeng.2017.01.374Peys, A., Rahier, H., & Pontikes, Y. (2016). Potassium-rich biomass ashes as activators in metakaolin-based inorganic polymers. Applied Clay Science, 119, 401-409. doi:10.1016/j.clay.2015.11.003Soriano, L., Font, A., Tashima, M. M., Monzó, J., Borrachero, M. V., & Payá, J. (2020). One-part blast furnace slag mortars activated with almond-shell biomass ash: A new 100% waste-based material. Materials Letters, 272, 127882. doi:10.1016/j.matlet.2020.127882Abdullah, H. H., Shahin, M. A., & Walske, M. L. (2020). Review of Fly-Ash-Based Geopolymers for Soil Stabilisation with Special Reference to Clay. Geosciences, 10(7), 249. doi:10.3390/geosciences10070249Cristelo, N., Miranda, T., Oliveira, D. V., Rosa, I., Soares, E., Coelho, P., & Fernandes, L. (2015). Assessing the production of jet mix columns using alkali activated waste based on mechanical and financial performance and CO2 (eq) emissions. Journal of Cleaner Production, 102, 447-460. doi:10.1016/j.jclepro.2015.04.102Font, A., Soriano, L., Moraes, J. C. B., Tashima, M. M., Monzó, J., Borrachero, M. V., & Payá, J. (2017). A 100% waste-based alkali-activated material by using olive-stone biomass ash (OBA) and blast furnace slag (BFS). Materials Letters, 203, 46-49. doi:10.1016/j.matlet.2017.05.129De Moraes Pinheiro, S. M., Font, A., Soriano, L., Tashima, M. M., Monzó, J., Borrachero, M. V., & Payá, J. (2018). Olive-stone biomass ash (OBA): An alternative alkaline source for the blast furnace slag activation. Construction and Building Materials, 178, 327-338. doi:10.1016/j.conbuildmat.2018.05.157Alonso, M. M., Gascó, C., Morales, M. M., Suárez-Navarro, J. A., Zamorano, M., & Puertas, F. (2019). Olive biomass ash as an alternative activator in geopolymer formation: A study of strength, radiology and leaching behaviour. Cement and Concrete Composites, 104, 103384. doi:10.1016/j.cemconcomp.2019.103384Vossen, P. (2007). Olive Oil: History, Production, and Characteristics of the World’s Classic Oils. HortScience, 42(5), 1093-1100. doi:10.21273/hortsci.42.5.1093Roig, A., Cayuela, M. L., & Sánchez-Monedero, M. A. (2006). An overview on olive mill wastes and their valorisation methods. Waste Management, 26(9), 960-969. doi:10.1016/j.wasman.2005.07.024García Martín, J. F., Cuevas, M., Feng, C.-H., Álvarez Mateos, P., Torres García, M., & Sánchez, S. (2020). Energetic Valorisation of Olive Biomass: Olive-Tree Pruning, Olive Stones and Pomaces. Processes, 8(5), 511. doi:10.3390/pr8050511Cosa, J., Soriano, L., Borrachero, M. V., Payá, J., & Monzó, J. M. (2019). Stabilization of soil by means alternative alkali‐activated cement prepared with spent FCC catalyst. International Journal of Applied Ceramic Technology, 17(1), 190-196. doi:10.1111/ijac.13377Xing, J., Zhao, Y., Qiu, J., & Sun, X. (2019). Microstructural and Mechanical Properties of Alkali Activated Materials from Two Types of Blast Furnace Slags. Materials, 12(13), 2089. doi:10.3390/ma12132089Burciaga-Díaz, O., & Escalante-García, J. I. (2013). Structure, Mechanisms of Reaction, and Strength of an Alkali-Activated Blast-Furnace Slag. Journal of the American Ceramic Society, 96(12), 3939-3948. doi:10.1111/jace.12620Gunasekaran, S., & Anbalagan, G. (2007). Thermal decomposition of natural dolomite. Bulletin of Materials Science, 30(4), 339-344. doi:10.1007/s12034-007-0056-zWalkley, B., San Nicolas, R., Sani, M.-A., Rees, G. J., Hanna, J. V., van Deventer, J. S. J., & Provis, J. L. (2016). Phase evolution of C-(N)-A-S-H/N-A-S-H gel blends investigated via alkali-activation of synthetic calcium aluminosilicate precursors. Cement and Concrete Research, 89, 120-135. doi:10.1016/j.cemconres.2016.08.010Puertas, F., Palacios, M., Manzano, H., Dolado, J. S., Rico, A., & Rodríguez, J. (2011). A model for the C-A-S-H gel formed in alkali-activated slag cements. Journal of the European Ceramic Society, 31(12), 2043-2056. doi:10.1016/j.jeurceramsoc.2011.04.036Ortega-Zavala, D. E., Santana-Carrillo, J. L., Burciaga-Díaz, O., & Escalante-García, J. I. (2019). An initial study on alkali activated limestone binders. Cement and Concrete Research, 120, 267-278. doi:10.1016/j.cemconres.2019.04.002Guettala, A., Abibsi, A., & Houari, H. (2006). Durability study of stabilized earth concrete under both laboratory and climatic conditions exposure. Construction and Building Materials, 20(3), 119-127. doi:10.1016/j.conbuildmat.2005.02.001Salim, R., Ndambuki, J., & Adedokun, D. (2014). Improving the Bearing Strength of Sandy Loam Soil Compressed Earth Block Bricks Using Sugercane Bagasse Ash. Sustainability, 6(6), 3686-3696. doi:10.3390/su6063686Font, A., Soriano, L., Tashima, M. M., Monzó, J., Borrachero, M. V., & Payá, J. (2020). One-part eco-cellular concrete for the precast industry: Functional features and life cycle assessment. Journal of Cleaner Production, 269, 122203. doi:10.1016/j.jclepro.2020.122203Luukkonen, T., Abdollahnejad, Z., Yliniemi, J., Kinnunen, P., & Illikainen, M. (2018). One-part alkali-activated materials: A review. Cement and Concrete Research, 103, 21-34. doi:10.1016/j.cemconres.2017.10.00

Formulation of alkali-activated slag binder destined for use in developing countries

[EN] Worldwide cement production is around 4.2 billion tons, and the fabrication of one ton of ordinary Portland cement emits around 900 kg of CO2. Blast furnace slag (BFS) is a byproduct used to produce alkali-activated materials (AAM). BFS production was estimated at about 350 million tons in 2018, and the BFS reuse rate in construction materials of developing countries is low. AAM can reduce CO2 emissions in relation to Portland cement materials: Its use in construction would be a golden opportunity for developing countries in forthcoming decades. The present research aims to formulate AAM destined for future applications in developing countries. Two activators were used: NaOH, Na2CO3, and a mixture of both. The results showed that compressive strengths within the 42¿56 MPa range after 28 curing days were obtained for the Na2CO3-activated mortars. The characterization analysis confirmed the presence of hydrotalcite, carbonated phases, CSH and CASH. The economic study showed that Na2CO3 was the cheapest activator in terms of the relative cost per ton and MPa of manufactured mortars. Finally, the environmental benefits of mortars based on this reagent were evidenced, and, in terms of kgCO2 emissions per ton and MPa, the mortars with Na2CO3 yielded 50% lower values than with NaOH.We would also like to thank the Spanish Government MINECO/FEDER (ECOSOST project RTI-2018-097612-B-C21) for supporting this research.Bella, N.; Gudiel, E.; Soriano Martinez, L.; Font-Pérez, A.; Borrachero Rosado, MV.; Paya Bernabeu, JJ.; Monzó Balbuena, JM. (2020). Formulation of alkali-activated slag binder destined for use in developing countries. Applied Sciences. 10(24):1-15. https://doi.org/10.3390/app10249088S1151024Statista Major Countries in Worldwide Cement Production from 2015 to 2019https://www.statista.com/statistics/267364/world-cement-production-by-country/Proaño, L., Sarmiento, A. T., Figueredo, M., & Cobo, M. (2020). Techno-economic evaluation of indirect carbonation for CO2 emissions capture in cement industry: A system dynamics approach. Journal of Cleaner Production, 263, 121457. doi:10.1016/j.jclepro.2020.121457Di Maria, A., Snellings, R., Alaerts, L., Quaghebeur, M., & Van Acker, K. (2020). Environmental assessment of CO2 mineralisation for sustainable construction materials. International Journal of Greenhouse Gas Control, 93, 102882. doi:10.1016/j.ijggc.2019.102882Hassan, A., Arif, M., & Shariq, M. (2019). Use of geopolymer concrete for a cleaner and sustainable environment – A review of mechanical properties and microstructure. Journal of Cleaner Production, 223, 704-728. doi:10.1016/j.jclepro.2019.03.051Recovery (Recycling Technology Worldwide) Slag Recyclinghttps://www.recovery-worldwide.com/en/artikel/slag-recycling_3528047.htmlVan Deventer, J. S. J., Provis, J. L., & Duxson, P. (2012). Technical and commercial progress in the adoption of geopolymer cement. 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New eco-cellular concretes: sustainable and energy-efficient material

[EN] Chemistry is an essential science for understanding and developing construction materials. Specifically, the application of the green chemistry concept to the cement sector may allow the fabrication of new environmentally friendly materials with good sustainability and energy efficiency. Cellular concretes are an excellent alternative to conventional concrete in terms of thermal insulation and material economy. In this paper, the development of waste-based cellular concrete is presented; due to its good performance and low environmental impact, this focus is warranted. Three different cellular concrete systems were investigated: (i) traditional cellular concrete based on ordinary Portland cement and commercial aluminium powder; (ii) geopolymer cellular concrete applying alkali-activated chemical technology with a comparison of the use of two precursors, fluid catalytic cracking catalyst residue (FCC) and blast furnace slag (BFS), and recycled aluminium foil as an aerating agent; (iii) eco-cellular concrete, where commercial waterglass was replaced by an agro-industrial by-product, rice husk ash (RHA), in the activating solution. The development of geopolymer cellular concretes with different precursors and activating solutions has proven that the production of this type of concrete using different types of precursors is possible, depending on the availability of by-products and wastes. The densities, compressive strengths, and thermal properties of the three cellular concrete systems are assessed and a complete study on the carbon footprints of the developed concretes is presented. The results show that the alternative concretes have densities from 474 to 813 kg m¿3 , with compressive strengths from 2.6 to 4.6 MPa and thermal conductivities from 0.083 to 0.281 W m¿1 K¿1. In the case of the cellular concrete prepared using RHA in the activating reagent, the heat released from the dissolution of NaOH pellets in water dissolved the soluble silica present in the ash. This production method resulted in a reduction of its carbon footprint by 78%.The authors acknowledge financial support from the Universitat Politecnica de Valencia (UPV) through the internal project GEOCELPLUS. The authors would also like to express special gratitude to Dr Mrs Josefa L. Rosello Caselles for the recycled aluminium foil and to the Electronic Microscopy Service of the UPV. Thanks are given to DACSA, Cementval and BPOil for supplying samples.Font-Pérez, A.; Borrachero Rosado, MV.; Soriano Martinez, L.; Monzó Balbuena, JM.; Mellado Romero, AM.; Paya Bernabeu, JJ. (2018). New eco-cellular concretes: sustainable and energy-efficient material. Green Chemistry. 20:4684-4694. https://doi.org/10.1039/c8gc02066c468446942