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238 results on '"Bignozzi, Maria Chiara"'

51. Mechanical Performance, Phase Evolution and Microstructure of Natural Feldspathic Solid Solutions Consolidated Via Alkali Activation: Effect of NaOH Concentration

Author

Nana, Achile, primary, Tomé, Sylvain, additional, Anensong, Sybilline Claudelle Djadock, additional, Venyite, Paul, additional, Djobo, Jean Noel Yankwa, additional, Ngouné, Jean, additional, Kamseu, Elie, additional, Bignozzi, Maria Chiara, additional, and Leonelli, Cristina, additional

Published
2021
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56. Design of inorganic polymer cements: effects of matrix strengthening on microstructure

Author

Kamseu, Elie, Bignozzi, Maria Chiara, Melo, U.C., Leonelli, Cristina, and Sglavo, Vincenzo M.

Subjects
Stability -- Research, Cement -- Chemical properties -- Research, Microstructure -- Research, Business, Construction and materials industries
Abstract

ABSTRACT The effects of bulk composition and microstructure on strengthening mechanisms and fracture resistance were investigated for metakaolin based geopolymers. Crack initiation and propagation under mechanical and environmental stresses were [...]

Published
2013
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57. A Comprehensive Microstructural and Compositional Characterization of Allogenic and Xenogenic Bone: Application to Bone Grafts and Nanostructured Biomimetic Coatings

Author

Graziani, Gabriela, primary, Govoni, Marco, additional, Vivarelli, Leonardo, additional, Boi, Marco, additional, De Carolis, Monica, additional, Bianchi, Michele, additional, Sassoni, Enrico, additional, Bignozzi, Maria Chiara, additional, Carnevale, Gianluca, additional, Marmi, Federico, additional, Maltarello, Maria Cristina, additional, and Dallari, Dante, additional

Published
2020
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58. Fly ash-based lightweight geopolymer mortars for fire protection

Author

Carabba, Lorenza, Gluth, Gregor J. G., Pirskawetz, Stephan M., Krüger, Simone, Bignozzi, Maria Chiara, Vyatcheslav Falikman, Roberto Realfonzo, Luigi Coppola, Petr Hàjek, Paolo Riva, Carabba, Lorenza, Gluth, Gregor J.G., Pirskawetz, Stephan M., Krüger, Simone, and Bignozzi, Maria Chiara

Subjects
Standard fire curve, Passive fire protection, Room temperature curing, Fly ash, Building and Construction, Materials Science (all), Alkali activated material, Geopolymer, Expanded perlite, Civil and Structural Engineering
Abstract

The present study aims to investigate the use of geopolymer mortars as passive fire protection system for steel structures. Coal fly ashes were used as aluminosilicate source and perlite was employed as aggregate to obtain a lightweight system. In addition, a geopolymer mortar containing quartz aggregate was produced for comparison. The geopolymer mortars were applied on stainless steel plates and exposed to both, cellulosic and hydrocarbon standard fire curves, according to ISO 834-1 and EN 1363-2, respectively. Acoustic emission measurements were conducted to analyze cracking phenomena during the high temperature exposure. The resulting temperature-time curves showed that the investigated system is effective in retarding the temperature rise of the steel plates. When the cellulosic fire curve was applied, a 20 mm [0.79 in.] thick layer of lightweight geopolymer mortar protected the steel substrate from reaching the critical temperature of 500 ?C [932 ?F] for at least 30 minutes, avoiding the rapid decrease of its mechanical properties and thus representing an important safety measure against accidental fires. No spalling phenomena on heating were detected; however, significant cracking was observed on cooling.

Published
2018

59. Protective treatments for lapped porcelain stoneware tiles and evaluation of their cleanability

Author

Rambaldi, Elisa, Lucchese, Beatrice, Bignozzi, Maria Chiara, Rambaldi, Elisa, Lucchese, Beatrice, and Bignozzi, Maria Chiara

Subjects
010302 applied physics, Materials Chemistry2506 Metals and Alloys, Materials science, General Chemical Engineering, Stain proofing agent, Ceramics and Composite, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Cleanability, Analytical Chemistry, Porcelain stoneware tiles, lcsh:TP785-869, lcsh:Clay industries. Ceramics. Glass, Lapping, 0103 physical sciences, Materials Chemistry, Ceramics and Composites, Porcelain stoneware tile, Chemical Engineering (all), Composite material, Physical and Theoretical Chemistry, 0210 nano-technology, Dirt resistance
Abstract

Since the arrival of lapped porcelain stoneware tiles on the market, several studies have been focused on the improvement of the technical characteristics of the surfaces of these products. Surface lapping induces aesthetical improvements, but can at the same time deteriorate the performance of porcelain stoneware tiles. To overcome this problem, it is possible to protect the lapped surface with commercial waterproofing materials. In this work, lapped commercial porcelain stoneware tiles with protective stain proofing agents (FILA PD15 and FILA 1239 Plus) were evaluated. The stain resistance and chemical resistance results were correlated to the morphological surface characteristics of the products with and without protection. A systematic study of the surface porosity of the tiles was carried out. Results showed that unprotected surface pores tend to fill with dirt that is hardly removable by ordinary maintenance. If the pores are protected, the dirt from foot traffic is deposited only superficially and can be removed.

Published
2017

62. Practical adhesion measurements of protective coatings on bronze by three-point bending test

Author

Aufray, Maëlenn, primary, Josse, Claudie, additional, Balbo, Andrea, additional, Monticelli, Cecilia, additional, Švara Fabjan, Erika, additional, Škrlep, Luka, additional, Kosec, Tadeja, additional, Gartner, Nina, additional, Martini, Carla, additional, Masi, Giulia, additional, Chiavari, Cristina, additional, Bernardi, Elena, additional, Bignozzi, Maria Chiara, additional, Robbiola, Luc, additional, Babnik, Marija, additional, Koršič, Teja, additional, and Kete, Marko, additional

Published
2019
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64. Binders alternative to Portland cement and waste management for sustainable construction—part 1

Author

Coppola, Luigi, primary, Bellezze, Tiziano, additional, Belli, Alberto, additional, Bignozzi, Maria Chiara, additional, Bolzoni, Fabio, additional, Brenna, Andrea, additional, Cabrini, Marina, additional, Candamano, Sebastiano, additional, Cappai, Marta, additional, Caputo, Domenico, additional, Carsana, Maddalena, additional, Casnedi, Ludovica, additional, Cioffi, Raffaele, additional, Cocco, Ombretta, additional, Coffetti, Denny, additional, Colangelo, Francesco, additional, Coppola, Bartolomeo, additional, Corinaldesi, Valeria, additional, Crea, Fortunato, additional, Crotti, Elena, additional, Daniele, Valeria, additional, De Gisi, Sabino, additional, Delogu, Francesco, additional, Diamanti, Maria Vittoria, additional, Di Maio, Luciano, additional, Di Mundo, Rosa, additional, Di Palma, Luca, additional, Donnini, Jacopo, additional, Farina, Ilenia, additional, Ferone, Claudio, additional, Frontera, Patrizia, additional, Gastaldi, Matteo, additional, Giosuè, Chiara, additional, Incarnato, Loredana, additional, Liguori, Barbara, additional, Lollini, Federica, additional, Lorenzi, Sergio, additional, Manzi, Stefania, additional, Marino, Ottavio, additional, Marroccoli, Milena, additional, Mascolo, Maria Cristina, additional, Mavilia, Letterio, additional, Mazzoli, Alida, additional, Medici, Franco, additional, Meloni, Paola, additional, Merlonetti, Glauco, additional, Mobili, Alessandra, additional, Notarnicola, Michele, additional, Ormellese, Marco, additional, Pastore, Tommaso, additional, Pedeferri, Maria Pia, additional, Petrella, Andrea, additional, Pia, Giorgio, additional, Redaelli, Elena, additional, Roviello, Giuseppina, additional, Scarfato, Paola, additional, Scoccia, Giancarlo, additional, Taglieri, Giuliana, additional, Telesca, Antonio, additional, Tittarelli, Francesca, additional, Todaro, Francesco, additional, Vilardi, Giorgio, additional, and Yang, Fan, additional

Published
2018
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69. Experiments and nanoscale simulations of geopolymers: porosity and molecular structure

Author

Lolli, Francesca, Masoero, Enrico, Cucinotta, Fabio, Manzi, Stefania, Bignozzi, Maria Chiara, G. Perkins, F. Lolli, E. Masoero, F. Cucinotta, M. C. Bignozzi, and S. Manzi

Subjects
porosity, molecular structure, nanoscale, geopolymer
Abstract

Cement production is responsible for approximately 9.5% of global anthropogenic CO2 emissions and as a consequence the increasing attention to sustainability issues has promoted research in alternative materials to cement paste, such as geopolymers. Current studies on geopolymers mainly focus on mechanical strength but research on their long-term mechanical performance and durability is still limited. Reducing the uncertainties around geopolymer durability requires a better understanding of the microstructural features and microscopic mechanisms that govern their chemo-mechanical behaviour. This can be pursued using simulations based on High Performance Computing (HPC), as previously experienced in the field of traditional cement. The aim of this study is to combine results from experimental analysis with HPC-based theoretical understanding of the fundamental mechanisms of material’s reactivity and ageing. The molecular structure of N-A-S-H (sodium aluminosilicate hydrate) geopolymer is considered as a model of metakaolin geopolymers. First results on molecular simulations based on a simplified crystalline version of N-A-S-H with hydrosodalite structure and Al/Si = 1 are discussed. The simulations indicate a path to develop a more fundamental understanding of Na-Si and Na-OH concentration effect on the porous structure and on the skeletal density.

Published
2016

73. Evaluation of durability and cleanability performances of protective treatments for lapped ceramic tiles ‐ Part 2.

Author

Rambaldi, Elisa, Lucchese, Beatrice, Engels, Marcel, and Bignozzi, Maria Chiara

Subjects
STONEWARE, CERAMIC tiles, DURABILITY, SURFACE roughness, POROSITY
Abstract

The aim of this work is to evaluate the cleanability performances of lapped porcelain stoneware surfaces with and without protective treatments. The knowledge of the material cleanability is an important selection parameter in buying tiles. However, an objective basis for testing and assessing this property still is lacking. In this study, standardized and laboratory tests to evaluate the cleanability performance of lapped porcelain stoneware products have been carried out and compared. Cleanability tests were performed by applying two different soiling suspensions, optimized for tile surfaces and reproducing chemical and mechanical actions simulating the working conditions and traditional cleaning operations. Surface characteristics (microstructure, topography, roughness) were analyzed before and after cleanability tests. The results showed a good correlation between different behavior in terms of cleanability and the microscopic and topographic characteristics of lapped tile. Respect to international standardized tests specific for ceramic tiles, such as stains resistance test, the laboratory procedures to evaluate the surface cleanability are able to better show cleanability improvements of lapped tiles with protective treatments. [ABSTRACT FROM AUTHOR]

Published
2019
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82. Superplasticizer Addition to Carbon Fly Ash Geopolymers Activated at Room Temperature.

Author

Carabba, Lorenza, Manzi, Stefania, and Bignozzi, Maria Chiara

Subjects
CARBON, SUPERPLASTICITY, FLY ash, POLYMERS, GLOBAL warming, EMISSIONS (Air pollution), PORTLAND cement
Abstract

Present concerns about global warming due to the greenhouse emissions in the atmosphere have pushed the cement industry to research alternatives to ordinary Portland cement (OPC). Geopolymer binder may constitute a possible breakthrough in the development of sustainable materials: understanding the effectiveness and the influences of superplasticizers on geopolymer systems is one of the essential requirements for its large-scale implementation. This study aims to investigate the possibility of using commercially available chemical admixtures designed for OPC concrete, to improve fresh properties of fly ash-based geopolymers and mortars. A special emphasis is laid upon evaluating their influence on mechanical and microstructural characteristics of the hardened material realized under room-temperature curing conditions. Results indicate that the addition of a polycarboxylic ether-based superplasticizer, in the amount of 1.0 wt. % by mass of fly ash, promotes an improvement in workability without compromising the final strength of the hardened material. Moreover, the addition of the polycarboxylic ether- and acrylic-based superplasticizers induces a refinement in the pore structure of hardened mortar leading to a longer water saturation time. [ABSTRACT FROM AUTHOR]

Published
2016
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100. Sustainable Cements for Green Buildings Construction.

Author

Bignozzi, Maria Chiara

Abstract

Abstract: The large amount of waste yearly disposed to landfill, the global impoverishing of natural resources and environment, the emergency of carbon dioxide emissions, are some of the motivations driving research institutes and industrial world to move towards sustainable solutions for civil engineering field. Accordingly, the use of sustainable materials for green buildings construction is an important goal that must be reached in short times. Sustainable cements can be designed by partially replacing clinker content with non hazardous waste. Indeed, recycling process can transform waste in secondary raw materials that work as new cement constituents usually leading to sustainable binders with peculiar environmental resistances. Details of cement manufacturing process and its effect on the environmental pollution as well as the route that can be carried out to tailor sustainable cements are reported and discussed. [Copyright &y& Elsevier]

Published
2012
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