Maria Chiara Bignozzi

University of Bologna | UNIBO

Alkali‐activated materials (AAMs) are binders that can complement and partially substitute the current use of conventional cement. However, the present knowledge about how AAMs protect steel reinforcement in concrete elements is incomplete, and uncertainties exist regarding the application of electrochemical methods to investigate this issue. The p...

Ceramic tile manufacturing is a highly energy-intensive process. Concerns about carbon emissions and energy costs make energy management crucial for this sector, which holds a leading role in Italian industry. The paper discusses the energetic and environmental performance of cogeneration (CHP) in the ceramic industry, where prime mover exhaust hea...

This study reports on the possibility of applying one-part pressed geopolymers as a support for microfiltration membranes. The mineralogical, physical, mechanical, microstructural and hydraulic properties of the investigated materials are presented. Metakaolin-based geopolymeric membrane flat supports were synthesized by uniaxial pressing a dry-mix...

A study about the performances of reclaimed asphalt pavement (RAP) sourced from 5 different Italian collection sites is presented to evaluate RAP as aggregate for concrete. Several RAP properties were investigated: physical properties (particles size distribution, water absorption, porosity, wettability), microstructure by microscopy, dimensional s...

Five different alkali activators were prepared by mixing sodium hydroxide with molar concentrations of 8, 10, 12, 14 and 16 M and sodium silicate, Na2SiO3 in volume ratio 1:1. The obtained alkaline activators were used for producing metakaolin/feldspathic rock-based geopolymer composites. These geopolymer composites were obtained by mixing differen...

Alkali activated materials and geopolymers have attracted a lot of attention in the last 20 years thanks to their excellent mechanical performances, durability and sustainability properties, especially for civil applications. These materials also exhibit promising properties as fire- and corrosion-resistant protection systems. In a previous study,...

The topic of sustainability of reinforced concrete structures is strictly related with their durability in aggressive environments. In particular, at equal environmental impact, the higher the durability of construction materials, the higher the sustainability. The present review deals with the possible strategies aimed at producing sustainable and...

Ceramic tiles are bacteriostatic materials; however, the COVID-19 emergency has pushed tile producers to improve surfaces’ antibacterial properties. The aim of this work was to validate a silver-based antibacterial treatment applied to porcelain stoneware tiles based on natural and waste materials, thus correlating surface functionalization to tile...

While cast geopolymers are deeply investigated, geopolymers shaped by pressing are still rather unexplored. This work aims at developing one-part pressed geopolymers investigating the influence of parameters such as Na/Al molar ratio, water content and pressure load on the physical, microstructural and durability properties of the hardened geopolym...

Air lime mortars with addition of two types of sesame cooking oil were synthesized and cured in two different conditions: laboratory and natural climatic conditions of the Pasargadae and Persepolis World Heritage Sites. For the mortars cured in the laboratory, addition of oils in the mortar induced hydrophobic effects, but it adversely affected on...

One-part or “just add water” alkali activated materials (AAMs) have attracted a lot of attention thanks to the use of solid alkaline activators that makes these materials more suitable to commercialization compared to conventional AAMs (two-part). This is mainly because large quantities of caustic solutions should be handled for producing conventio...

The Frontiers in Materials Editorial Office team are delighted to present the inaugural “Women in Science: Materials” article collection, showcasing the high-quality work of women in science across the breadth of materials science and engineering. All researchers featured within this collection were individually nominated by the Topic Editors in re...

According to UNESCO Institute for Statistics (UIS) data (UIS fact sheet, 2019), less than 30% of researchers worldwide are women. Long-standing biases and gender stereotypes are discouraging girls and women away from science related fields. In particular, STEM (science, technology, engineering and mathematics) research is traditionally male dominat...

Ceramic tile production is an industrial process where energy efficiency management is crucial, given the high amount of energy (electrical and thermal) required by the production cycle. This study presents the preliminary results of a research project aimed at defining the benefits of using combined heat and power (CHP) systems in the ceramic sect...

The inaugural "Women in Science : Materials" collection in "Frontiers in Materials" showcases the standout research of female researchers across the breadth of the materials science and engineering. It gathers a selection of 32 articles with the lead author and/or corresponding author being a woman. Manuscripts span all sections of the journal, the...

This chapter deals with innovative applications of photocatalytic TiO2 in different building materials, with particular reference to cement-based materials (concrete, mortars, and pavements) and tiles, which are omnipresent materials in constructions. The possibility of manufacturing materials with antipollution, self-cleaning, and antimicrobial su...

Sustainable development has recently become the driving force of all the policies leading environmental, economic, and social aspects of our life. In the construction sector, a large number of technological innovations has been introduced thus leading to an assessment of the environmental impact of the production processes. In the present study, th...

Application of protective coatings is the most widely used conservation treatment for outdoor bronzes. Eco-friendly and non-hazardous coatings are currently needed for conservation of outdoor bronze monuments. To fulfil this need, the M-ERA.NET European research project B-IMPACT (Bronze-IMproved non-hazardous PAtina CoaTings) aimed at assessing the...

The RILEM technical committee TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ conducted a round robin testing programme to determine the validity of various durability testing methods, originally devel-oped for Portland cement based-concretes, for the assessment of the durability of alkali-activated concretes. The outcomes of the roun...

Results of three-point bending tests on notched beams cast with three alkali-activated mortars that differ by the type and size of the aggregates are presented. Digital image correlation is used to estimate the size of the fracture process zone. The fracture energy is computed by means of the work-of-fracture method and found to be strongly depende...

Research in alkali-activated materials (AAMs) is an innovative and dynamic material science topic. This is due to the relevant performances in terms of physico-mechanical properties Q6 comparable to traditional construction materials (e.g., ordinary Portland cement). The sustainability of AAMs is often highlighted since they can be developed by usi...

In this study, considerations for design, characterization, and in-situ application of sustainable materials for restorative use in the Pasargadae world heritage site are discussed. Based on some prior studies on sustainable waste-based restorative mortars, air lime mortars were made from lime putty, mixture of stones from the site, and additive se...

A ready-to use, highly sustainable solution for large scale exhausts catalytic abatement was developed: the active bricks. An environmentally-friendly composite was synthesized by depositing La0.6Sr0.4Ga0.3Fe0.7O3, by combustion synthesis, on a fly ash-based geopolymer improved to bear the high temperatures (> 900 °C) required for synthesis. The ge...

Bone grafts and bone-based materials are widely used in orthopedic surgery. However, the selection of the bone type to be used is more focused on the biological properties of bone sources than physico-chemical ones. Moreover, although biogenic sources are increasingly used for deposition of biomimetic nanostructured coatings, the influence of speci...

The application of protective coatings for the conservation of outdoor metallic artworks is currently considered the best approach actively employed. This paper focuses on the evaluation of the protectiveness of an optimised fluorosilane (FA-MS) coating with low occupational hazard impact and high inhibition efficiency. FA-MS coating was applied on...

This work aims to prepare low-cost nanocomposite and microcomposite with lower molar ratio CaO/SiO 2 (0.4). Nano-silica, rice husk ash and calcined chicken eggshell have been used as silica and calcium sources. Metakaolin has been separately replaced by 0, 10 and 20 wt% of each composite in order to study their behavior on the properties of geopoly...

Purpose Alkali-activated materials, also known as geopolymers, are considered promising assets in the sustainable materials industry. Given the excellent properties in terms of thermal stability and low thermal conductivity, geopolymer-based matrices can effectively substitute cementitious binders in the preparation of passive fire protection (PFP)...

The objective of this paper is to review the current knowledge on the development of nanostructured zirconia-based ceramics and composites suitable for application in dentistry. Isi Web of Science, Science Direct, Scientific.net databases, and Google were searched electronically for the period of 1980 to the present, matching the keywords “nano” wi...

This study aims at investigating the use of coal fly ash-based alkali activated mortars as passive fire protection system for steel structures. These systems are used to slow down the temperature rise of the steel substrate in case of fire. In addition, the protective system should guarantee the ability to prevent and/or mitigate steel corrosion ph...

A two-year M-ERA.NET project – the Bronze-IMproved non- hazardous PAtina CoaTings project (B-IMPACT) – focused on this conservation issue with the aim of promoting innovative, eco- friendly, and non-hazardous protection treatments for outdoor patinated bronze. Two types of sand-cast bronzes (traditional Cu-Sn-Zn-Pb and modern Cu-Si-Mn foundry alloy...

In the present work the microstructural characterization of the powder-metallurgy X190CrVMo20-4-1 has been performed and correlated with its corrosion properties. The martensitic stainless steel was hardened at different austenitizing and tempering temperatures. Microstructural analyses were carried out using Scanning Electron Microscopy (SEM–EDS)...

The sustainable microcomposites with different molar ratios CaO/SiO2 such as 0, 0.4, 0.6, 0.8, 1.0 and 1.2 were prepared using calcined brown chicken eggshell, rice husk ash and distilled water. 10 wt% of each microcomposite was used to substitute metakaolin and the obtained calcium aluminosilicate materials were used for investigating the effects...

When attempting to sufficiently protect outdoor bronze monuments from corrosion, searches for an effective solution are usually based on coating applications which have a high anticorrosive efficiency. In order to correctly assess the level of protection provided by such coatings, adherence (practical adhesion) measurements need to be performed for...

This work focuses on an in-depth investigation of the formation of pores in the structure of lightweight geopolymer cements and mortars using rice husk as a foaming agent. The hardener used in this study was sodium waterglass. Metakaolin was replaced by 0, 10, 20, 30 and 40 % by mass of husk and the obtained powders were used to produce lightweight...

Alkali-activated fly ashes have been proposed for various applications where resistance against high temperatures is required, yet several details regarding the response of these materials to heat-exposure need to be clarified. In the present study, heat-induced cracking in fly ash-based alkali-activated pastes and lightweight mortars was analyzed...

Surface coatings made of hydroxyapatite (HAP) have been proposed to protect marble artworks from dissolution in rain, originated by the aqueous solubility of calcite. However, HAP coatings formed by wet chemistry exhibit incomplete coverage of marble surface, which results in limited protective efficacy. In this study, electrodeposition was explore...

A mild chelating agent treatment was performed on the residuals of the sorting processes of separately collected urban glass, which is currently landfilled. This fraction, that represents about the 10 wt% of the overall collected glass, has a very heterogeneous composition and contains relatively high amounts of lead and barium and consequently can...

A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by “liver of sulphur”, was investigated as a non-toxic alternative to Incralac®, usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and ac- celerated corrosion test s...

Alkali activated lightweight mortars, obtained by room temperature activation of coal fly ash, were studied as passive fire protection systems for steel elements. Physical, mechanical and thermal properties were investigated as a function of the compositional Si/Al molar ratio and of the amount of lightweight aggregate and foaming agent. Experiment...

The aim of this work is to evaluate the durability, in real pedestrian traffic condition, of lapped porcelain stonewares with surface protective treatments able to fill up pores opened by the lapping process. In recent years, the durability of ceramic surfaces has become a key factor during the design process. The knowledge of the material durabili...

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 the present study, s...

Air- and formulated lime mortars with pulverized brick waste were synthesized with addition of two organic waste-based additives: spent cooking oil and albumen. The addition of spent oil in the mortar induced significant hydrophobic effects, but decreased permeability values and setting kinetics. Parallel additions of oil and albumen in lime mortar...

The paper represents the "state of the art" on sustainability in construction materials. In Part 1 of the paper, issues related to production, microstructures, chemical nature, engineering properties, and durability of mixtures based on binders alternative to Portland cement were presented. This second part of the paper concerns the use of traditio...

This review presents "a state of the art" report on sustainability in construction materials. The authors propose different solutions to make the concrete industry more environmentally friendly in order to reduce greenhouse gases emissions and consumption of non-renewable resources. Part 1-the present paper-focuses on the use of binders alternative...

The compaction behavior of spray-dried powders has turned into concern in porcelain stoneware manufacturing due to the increasing diffusion of large slabs. It is necessary to fill a knowledge gap between the compaction behavior with conventional presses and novel technologies. For this purpose, eighteen industrially-manufactured spray dried bodies...

The technological behavior of porcelain stoneware bodies during deposition and pressing of large slabs depends on the rheological properties of spray-dried powders and the way they affect compaction. Although the literature offers some insights into the characteristics of spray-dried powders for ceramic tiles, no data are available on bodies utiliz...

The paper describes part of the preliminary results of the of the MATERSOS project, funded by the Emilia Romagna Region, Italy. This research project aims at implementing circular economy processes in the constructions industry, through the usage of secondary raw materials. The present paper focuses on structural concrete. After an analysis of loca...

Dicalcium phosphate dihydrate (DCPD) and hydroxyapatite (HAP) were prepared from oyster shell powder and phosphoric acid solution as raw materials using sol-gel process in order to study the influence of calcium phosphate compounds on the mechanical and microstructural properties of metakaolin-based geopolymer cements. The synthesized DCPD and HAP...

This paper investigates the shrinkage and creep of self-compacting concrete prepared with coarse and fine recycled concrete aggregates (up to 40% of total amount of aggregates). Physical properties and porosity measurements are studied and related to the mechanical properties. Results highlight that self-compacting characteristics are maintained wh...

Glass with different chemical compositions, deriving from separate collection, has been used as fine aggregate to formulate cementitious mortars, substituting natural sand. Glass coming from cathode-ray tube monitors, fluorescent lamps, and crystal glass (from production of home décor items) along with glass deriving from soda-lime glass containers...

Application of a protective coating is the most widely used conservation treatment for outdoor bronzes (cast Cu-Sn-Zn-Pb-Sb alloys). However, improving coating protectiveness requires detailed knowledge of the coating/substrate chemical bonding. This is particularly the case for 3-mercapto-propyl-trimethoxy-silane (PropS-SH) applied on bronze, exhi...

This study aims to develop innovative and sustainable alkali-activated composites with enhanced performance at high temperatures. To reduce production costs and promote a circular economy model, coal fly ashes are selected as a precursor for the alkali activation and recycled refractory particles are used to develop products with high thermal dimen...

The suitability of new lime mortars for restorative rendering applications was investigated. Air-, formulated- and hydraulic-lime mortars were synthesized with inclusion of two different types of spent sunflower cooking oils and, when necessary, brick waste powder as pozzolanic addition. The results of spent cooking oils addition in the mortars exh...

In order to bring the treatment of historical bronze monuments in line with proper engineering practice and cultural heritage regulations, the standardisation of artificially aged surfaces that are comparable with natural ones is still to take place. In this aim, this investigation reports a comparative study of corroded quaternary bronze samples p...

Steel fiber reinforced geopolymer matrix (S-FRGM) composites are explored as a new tool in strengthening applications of reinforced concrete (RC) structures. The suitability of fly ash geopolymers as the matrix employed in S-FRGMs is investigated in this paper. Geopolymer matrix is used to embed galvanized steel fibers and bond the composite to a c...

This article investigates the effect of a low-impact chemical treatment based on a nitrilotriacetic acid chelating agent on the reactivity of funnel glass derived from discarded cathode ray tubes. Treated and untreated glass has been recycled either as a supplementary cementing material or as a fine aggregate in cementitious mortars. The effect of...

Glazed ceramic tiles are characterised by a good chemical durability excepting in highly alkaline and acid environment. A continual use of cleaning agents with a basic or acid pH on ceramic flooring, could give rise to a lowering of mechanical performances due to the corrosion of crystalline phases more than the amorphous phase. In the present work...

The response to thermal variations is the primary cause of marble deterioration in ancient and modern buildings. In this study, the thermal behavior of Carrara marble after consolidation by an innovative hydroxyapatite-based treatment was investigated in comparison with ammonium oxalate and ethyl silicate. Samples were subjected to heating-cooling...

Porcelain stoneware tiles are industrially processed by using high sintering temperatures and fast firing cycles that result in products characterized by an almost impervious surface layer surrounding a rather porous bulk material. Since mechanical properties are affected by porosity, the knowledge of the material stiffness is an important paramete...

This paper aims at evaluating how the FRP/brick debonding force is influenced by brick mechanical properties (compressive, tensile and flexural strength) and physical-microstructural properties (surface roughness, porosity, pore size distribution, rate of water capillary suction). The depth of epoxy resin penetration into bricks and the thickness o...

Outdoor bronzes suffer corrosion phenomena that generate partially protecting layers called patina. In urban atmosphere, the action of the environment makes these patinas partially leached away by rainwater. Moreover, the geometry of exposure influences the corrosion behaviour: in particular, different kinds of patinas are formed in “sheltered” or...

This research investigates the corrosion protection afforded to the embedded rebars by room temperature-cured alkali-activated mortars, based on class F fly ash (FA), during wet and dry (w/d) exposures to 0.1 M NaCl solution. The results were compared to those obtained in a traditional cement-based mortar (REF). The rebar corrosion behaviour was ch...

To enhance structural safety of existing masonries, FRP application is an effective strategy. Alongside the nature and characteristics of fibers and matrix, mechanical properties of bricks are generally recognized as the most important parameters affecting the FRP/masonry strength of adhesion. However, additional parameters may play an important ro...

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 m...