Article
Construction & Building Technology
Jie Shi, Jinguang Zhao, Heng Chen, Pengkun Hou, Shiho Kawashima, Jihui Qin, Xiangming Zhou, Jueshi Qian, Xin Cheng
Summary: The acid resistance performance of magnesium phosphate cements is of great importance and this study found that magnesium ammonium phosphate cement has better resistance to sulfuric acid than magnesium potassium phosphate cement.
CEMENT AND CONCRETE RESEARCH
(2022)
Article
Construction & Building Technology
Biwan Xu, Frank Winnefeld, Barbara Lothenbach
Summary: The study shows that hydration of MKP cement at 50 degrees Celsius leads to the gradual decomposition of K-struvite, but the addition of wollastonite can significantly slow down this process, maintaining the strength of the cement. The products formed from the reaction with wollastonite contribute to the good strength of the cement at both 20 and 50 degrees Celsius.
CEMENT AND CONCRETE RESEARCH
(2021)
Article
Construction & Building Technology
Baki Aykut Bilginer, Sinan T. Erdogan
Summary: The study found that factors like magnesium-to-phosphate ratio and water-to-binder ratio have significant effects on setting time and early strength of MKPC pastes, while the addition of borax, fly ash, and sand does not significantly alter the mineralogy of hydrated pastes.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Biwan Xu, Frank Winnefeld, Bin Ma, Daniel Rentsch, Barbara Lothenbach
Summary: Aluminum sulfate has a positive effect on preventing efflorescence of magnesium potassium phosphate cements by modifying the cement properties and hydration process.
CEMENT AND CONCRETE RESEARCH
(2022)
Article
Construction & Building Technology
Biwan Xu, Barbara Lothenbach, Zongjin Li
Summary: The effects of seawater on properties and hydrates of MKP cement are complex, including prolonging setting time, slowing down heat release, increasing compressive strength, but decreasing water resistance. The main hydrate formed in seawater is K-struvite, with additional minor components present.
CEMENT & CONCRETE COMPOSITES
(2022)
Article
Chemistry, Multidisciplinary
Yongshan Tan, Laura J. Gardner, Brant Walkley, Oday H. Hussein, Hao Ding, Shikuan Sun, Hongfa Yu, Neil C. Hyatt
Summary: The effect of ultrafine fly ash (UFA) and fly ash (FA) on the physical properties and micro-structure of magnesium potassium phosphate cement (MKPC) was studied. UFA addition did not affect the hydration peak of MKPC formation but led to increased reaction duration and potential formation of secondary reaction products. The addition of a UFA:FA blend delayed the hydration and setting time of MKPC. MgKPO4 center dot 6H2O was the main crystalline phase observed, but Mg2KH(PO4)2 center dot 15H2O was also observed at low replacement levels in the UFA-only system. UFA and UFA:FA acted as fillers and diluents. The optimized formulation with 40 wt % fly ash (10 wt % UFA and 30 wt % FA) achieved the highest compressive strength and fluidity, producing a dense microstructure.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Construction & Building Technology
Biwan Xu, Celine Cau Dit Coumes, David Lambertin, Barbara Lothenbach
Summary: The behavior of Magnesium potassium phosphate (MKP) cements in different environments was investigated using diluted nitric acid, water, and simplified Portland cement pore solution. The main hydrate K-struvite is destabilized to bobierrite at pH = 7 and to brucite and hazenite at pH > 7. Addition of wollastonite slows down compressive strength development in MKP cements but prevents strength loss with time.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Rita Gelli, Monica Tonelli, Francesca Martini, Lucia Calucci, Silvia Borsacchi, Francesca Ridi
Summary: This study explores the concentration dependent retarding effect of borax on tri-magnesium phosphate-based cements for the first time. By investigating the hydration and phases formed in the set cements using multiple characterization techniques, it was found that borax slows down the hydration process, reduces heat release, and leads to the formation of struvite instead of newberyite, without affecting the strength of the cement. The observed boron species suggest that the retardation is caused by the complexation of NH4+ and Mg2+ ions with borate and polyborate anions.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Engineering, Biomedical
Friederike Kaiser, Lena Schroeter, Svenja Stein, Benjamin Krueger, Jan Weichhold, Philipp Stahlhut, Anita Ignatius, Uwe Gbureck
Summary: Results of several studies have shown that magnesium phosphate cements (MPCs) have excellent biocompatibility, osteoconductivity, and higher solubility compared to calcium phosphates, making them promising alternatives to slowly degrading calcium phosphate cements. Decreasing the powder-liquid ratio (PLR) of the cement can further improve the degradation speed, with the potential for fast bone ingrowth within a few months. However, further modifications may be needed, especially for the K-struvite cement, to achieve a slower resorption and reduced inflammatory response in vivo.
ACTA BIOMATERIALIA
(2022)
Article
Chemistry, Physical
Andrea Ewald, Andreas Fuchs, Lasse Boegelein, Jan-Peter Grunz, Karl Kneist, Uwe Gbureck, Stefanie Hoelscher-Doht
Summary: The use of bone-cement-enforced osteosynthesis is a growing topic in trauma surgery. This study evaluated a resorbable and drillable magnesium-phosphate-based cement paste and found that it has promising degradation behavior and biocompatibility in vivo.
Article
Nuclear Science & Technology
Jae-Young Pyo, Wooyong Um, Jong Heo
Summary: This study demonstrates that MKPCs can effectively immobilize radioactive concrete wastes generated by the decommissioning of nuclear power plants. The addition of simulated concrete powder wastes reduces porosity and increases compressive strength of MKPC specimens. MKPCs maintain satisfactory compressive strength and leachability indices after thermal cycling and immersion.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2021)
Article
Materials Science, Ceramics
Polina A. Krokhicheva, Margarita A. Goldberg, Alexander S. Fomin, Dinara R. Khayrutdinova, Olga S. Antonova, Alexander S. Baikin, Anatoliy A. Konovalov, Aleksander V. Leonov, Ivan V. Mikheev, Ekaterina M. Merzlyak, Valentina A. Kirsanova, Irina K. Sviridova, Natalia S. Sergeeva, Sergey M. Barinov, Vladimir S. Komlev
Summary: This study aims to develop magnesium calcium phosphate bone cements (MCPCs) with antibacterial properties by incorporating silver ions. Increasing the silver ion concentration significantly improved the mechanical properties of the cements (compressive strength reached 41 +/- 2 MPa) and exhibited an 8 mm inhibition zone against Escherichia coli and Staphylococcus aureus in a disk diffusion test, without toxicity to MG-63 cells in vitro. Analysis of the MCPC samples soaked in Kokubo's simulated body fluid showed the formation of merrillite phase on the surface, transforming into bobierrite phase after 28 days of soaking. Histological examination and micro-CT analysis confirmed the osteoconductive and biodegradable nature of the newly developed MCPCs, making them suitable as bone substitutes.
CERAMICS INTERNATIONAL
(2023)
Article
Construction & Building Technology
Yao Xiao, Yu Jiang, Bing Chen, Liyan Wang
Summary: This paper investigates the effects of red mud substitution on the performance of magnesium phosphate cement (MPC). The incorporation of red mud prolongs the setting time and reduces the hydration reaction intensity. It significantly improves the compressive strength of hardened MPC mortars.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
R. Perona, C. Fernandez-Garcia, I. Garcia-Lodeiro, M. Criado, J. M. Bastidas, M. C. Alonso
Summary: Magnesium potassium phosphate cement (MKPC) is a potential replacement for ordinary Portland cement (OPC) in the encapsulation of low-level radioactive waste and improvement of the corrosion behavior of reactive metals. This study investigated the corrosion behavior of pure aluminum (A1050) and aluminum-magnesium alloy (AA5754) in MKPC and OPC mortars, and assessed the effect of curing conditions on the hardening properties and reactivity of these metals. The results showed that AA5754 exhibited significantly lower corrosion rate and hydrogen evolution in MKPC compared to OPC, with average corrosion current density values of 1.85 and 109.0 x 10-6 A/cm2, and hydrogen volumes of 0.33 L/m2 and 17.8 L/m2 for AA5754/MKPC and AA5754/OPC, respectively. The pH of the pores was close to neutral and the hardening properties were highly influenced by the curing conditions.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Construction & Building Technology
E. Qoku, M. Scheibel, T. Bier, A. Gerz
Summary: This study focused on the development of solid phase assemblages in four different magnesium phosphate cements at room temperature and elevated temperatures. The main hydration products formed under different conditions were identified and analyzed, showing changes in phase assemblages at different temperatures.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Correction
Materials Science, Multidisciplinary
Radek Sevcik, Alberto Viani, Lucia Mancini, Marie-Sousai Appavou, Dita Machova
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Ceramics
Lucie Zarybnicka, Petra Macova, Alberto Viani
Summary: A novel ceramic composite achieved through the introduction of polyvinyl alcohol and cross-link reaction exhibited beneficial effects such as extended working time, reduced water sensitivity, and decreased heat evolution rate.
CERAMICS INTERNATIONAL
(2022)
Article
Archaeology
Jose Diaz, Radek Sevcik, Petra Macova, Beatriz Menendez, Dita Frankeova, Zuzana Slizkova
Summary: This paper presents an experimental assessment of the effects of silica nanoparticles on lime restoration mortars. The results show that the application of nanosilica can improve the mechanical performance and affect the mineralogical composition and carbonation rate of lime. The usage of nanosilica without further additives can be used to tune the properties of air and hydraulic limes according to the specific requirements for the restoration of cultural heritage objects.
JOURNAL OF CULTURAL HERITAGE
(2022)
Article
Construction & Building Technology
Konstantinos Sotiriadis, Radoslaw Mroz, Petra Macova, Anton S. Mazur, Andraz Krajnc
Summary: Synthesized cement systems with different C3A/C4AF ratios were tested under long-term humid conditions to assess the changes in crystalline and amorphous phases. The findings indicate that systems with C3A/C4AF < 1 better preserved the integrity of the C-S-H phase and prevented thaumasite formation. Addition of calcite inhibited carbonation reactions.
CEMENT AND CONCRETE RESEARCH
(2022)
Article
Materials Science, Ceramics
Lucie Zarybnicka, Jana Machotova, Petra Macova, Alberto Viani
Summary: The role of carboxyl functional groups in acrylic latex on fabricating an organic-inorganic composite material based on magnesium phosphate cement was investigated. The acidic nature of the latex aqueous medium enhanced the dissolution of magnesium oxide in the initial stages of the cement reaction. The deprotonation of carboxyl groups due to increased pH promoted surface adsorption effects, which controlled the nucleation and growth of reaction products. The resulting hindering effect slowed down reaction rates, delaying the precipitation of solid phosphates and leading to improved properties of the composite.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Alberto Viani, Petra Macova, Radek Sevcik, Lucie Zarybnicka
Summary: Citric acid enhances the dissolution of MgO and delays the nucleation of phosphates in magnesium phosphate cements. Citrates complex the released Mg2+ ions, reducing the degree of supersaturation. The adsorption of citrate hinders crystal growth and amorphous-to-crystalline transformation.
CERAMICS INTERNATIONAL
(2023)
Article
Thermodynamics
Pavla Bauerova, Magdalena Kracik-Storkanova, Petra Macova, Pavel Reiterman, Eva Vejmelkova, Martin Keppert
Summary: This paper investigates the possibility of using thermal analysis to estimate the linseed oil content in historic mortar. By studying model mortar samples, a calculation method and mass spectroscopy analysis were proposed to determine the oil content, and it was found that the mass spectroscopy analysis method yielded the most accurate results.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Construction & Building Technology
Lucie Zarybnicka, Jaroslav Pokorny, Jana Machotova, Radek Sevcik, Jiri Sal, Alberto Viani
Summary: New acrylic latex additives with and without keto-hydrazide crosslinking were prepared and incorporated into Portland cement-based mortars. The results showed that the latexes without crosslinking had the highest effect on heat flow evolution. The addition of both latex types increased the open porosity and decreased the mechanical strength of the cement composites, but improved the liquid water transport properties.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Materials Science, Ceramics
Davide Bernasconi, Alberto Viani, Lucie Zarybnicka, Petra Macova, Simone Bordignon, Caterina Caviglia, Enrico Destefanis, Roberto Gobetto, Alessandro Pavese
Summary: This study investigates the incorporation of solid waste incineration fly ash into phosphate-based geopolymers as a substitute for metakaolin. Analytical techniques such as X-ray diffraction, scanning electron microscopy, solid-state nuclear magnetic resonance spectroscopy, and infrared spectroscopy were used to analyze the changes in mineralogy and structural modifications of the geopolymer networks, which affected the mechanical performance of the materials. The results show that fly ash behaves differently from metakaolin, primarily acting as an alkali source and competing with the aluminosilicate metakaolin fraction by precipitating crystalline and amorphous phosphates. The substitution of 10% metakaolin with fly ash preserves the amorphous geopolymer matrix and retains the mechanical properties. However, at higher waste content (30-50% wt), the fast acid-base reactions involving the fly ash reactive phases dominate, leading to a shift in the material nature towards an alkali-phosphate cement/phosphate-geopolymer composite. This change, along with the development of porosity and the presence of low-strength phases in the ash, results in a decline in mechanical performance. Overall, this work provides valuable information for the sustainable utilization of phosphate-based geopolymers, while highlighting the recycling potential for this type of fly ash.
CERAMICS INTERNATIONAL
(2023)
Article
Archaeology
Radek Sevcik, Jana Machotova, Lucie Zarybnicka, Petra Macova, Alberto Viani
Summary: This investigation evaluates the use of polyacrylate latex nanodispersions as consolidation agents for sandstones. Four types of latex with different polymer fluorination and crosslinking have been synthesized and tested on Prague sandstone. The consolidated stone samples showed significant improvements in mechanical properties, even with diluted latex nanodispersions, while maintaining comparable moisture transport properties. The flexibility of the chemical properties of these novel nanodispersions allows for customized treatments to preserve cultural heritage objects at risk from climate change.
JOURNAL OF CULTURAL HERITAGE
(2023)
Article
Crystallography
Alberto Viani, Lucie Zarybnicka, Radek Sevcik, Petra Macova, Jana Machotova
Summary: The mechanisms of how EDTA and NTA sodium salts control the precipitation of struvite-K from solution have been investigated. These additives influence the precipitation process by extending the induction time, reducing the crystallization rate, and decreasing the amount of reaction product.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Chemistry, Multidisciplinary
Abu Talha Aqueel Ahmed, Sankar Sekar, Shubhangi S. Khadtare, Nurul Taufiqu Rochman, Bathula Chinna, Abu Saad Ansari
Summary: In this study, MnCo2S4 nanosheet catalyst was successfully synthesized and found to exhibit superior performance in hydrogen evolution. Compared to MnCo2S4, MnCo2S4 showed low overpotentials, moderate Tafel slope, and excellent sustainability. The outstanding performance can be attributed to the increased number of electrochemically active sites and enhanced electronic conductivity on the catalyst surface.
Article
Chemistry, Multidisciplinary
Victor V. Maltsev, Elena A. Volkova, Elizaveta V. Koporulina, Diana D. Mitina, Vladimir L. Kosorukov, Anna I. Jiliaeva, Daniil A. Naprasnikov, Konstantin N. Gorbachenya, Viktor E. Kisel
Summary: The phase relationships, crystal properties and luminescence kinetics of two complex systems were studied, including unit cell parameters, segregation coefficients of impurities, and lifetimes of energy levels.
Article
Chemistry, Multidisciplinary
Xiaoman Zhang, Wangwang Xu, W. J. Meng, Andrew C. Meng
Summary: This study successfully grew high-quality single crystal AlScN nanowires through ultra-high vacuum reactive sputtering technique and characterized their structure and properties. The nanowires exhibit significantly reduced mosaic spread and predominantly single ferroelectric domains, as well as a high piezoelectric constant.
Article
Chemistry, Multidisciplinary
Tom E. de Vries, Elias Vlieg, Rene de Gelder
Summary: Networks are important for describing relationships between people, roads between cities, reactions between chemicals, and other interactions. Bipartiteness, dividing the network into two groups, can facilitate the study of the network's structure. We have developed an algorithm that can find a near-optimal bipartisation within a reasonable time frame and used it to uncover the hidden structure of the CSD cocrystal network.
Article
Chemistry, Multidisciplinary
Chuchu Han, Jing Yang, Xin Zhang, Aisen Li, Jiang Peng
Summary: An elastic crystal based on a photo-reactive acylhydrazone derivative is reported, which exhibits reversible bending behavior under UV irradiation and heating. The crystal undergoes reversible E<->Z isomerization under light and heating conditions. The crystal demonstrates excellent elastic properties and the bending can be controlled to control the output direction of red light.
Article
Chemistry, Multidisciplinary
Lingfeng Zhang, Yu Wang, Yefeng Wang, Shuai Liu, Na Zhang, Mingmin Yang, Haixia Ma, Zhaoqi Guo
Summary: This study designs and synthesizes a series of high-energy salts compounds without heavy metal ions and azide groups. The molecular structures and stability of the compounds are confirmed through single-crystal X-ray diffraction and intermolecular interaction analysis. Furthermore, the thermal stability, energetic properties, and electrical initiation properties of the compounds are investigated, suggesting their potential as primary explosives.