In recent years, kaolinite‐based wastes are focusing the attention of researchers to obtain recycled metakaolinite, with consequent environmental and socioeconomic benefits. One of these lines of ...research is based on coal mining waste, which once activated thermally, it becomes a highly pozzolanic product (ACM). This study reports the influence of activated carbon mining waste on the formation and evolution of the mineralogical phases in the ACM/cement system as well as their influence on the microstructure up to 90 d of reaction. Mineralogical analyses clearly show that the addition of ACM modified mineralogical compounds of blended cements. The C4AH13 and C4AC¯H12 were the predominant phases in this type of cements; while in the ordinary portland cement cements, portlandite, ettringite, and carboaluminate were main hydrated phases. Two differential zones in the pore size distribution of the C–S–H gels at 12 and 4.5 nm were observed, predominating the formation of C–S–H gels at 12 nm when 20% of ACM was added to the cement.
Specific strategies for protection are being developed to counter both the staining and corrosive effects of polluted air in cities, as well as to allow for efficient removal of unwanted graffiti ...paintings. These protection strategies employ molecules with tailored functionalities, e.g. being hydrophobic, while maintaining porosity for molecular water vapour permeation. The present study employs SO2 and water to probe the behaviors of two anti-graffiti treatments, a water-base fluoroalkylsiloxane ("Protectosil Antigraffiti" marketed by Degussa) and an organically modified silicate (Ormosil) synthesized from a polymer chain (polydimethyl siloxane, PDMS) and two network forming alkoxides (Zr propoxide and methyl triethoxy silane, MTES) dissolved in n-propanol, on five building materials, comprising limestone, aged lime mortar, hydrated cement mortar, granite, and brick material. The materials were exposed to a synthetic atmosphere for 20h in a climate chamber, 0.78A plus or minus 0.03ppm of SO2 and 95% RH. Diffuse reflectance Fourier transform infrared (DR-FTIR) spectra were registered before and after exposure in the climate chamber in the cases of both treated and untreated samples. DR-FTIR, scanning electron microscope (SEM) images and energy dispersive X-ray (EDX) analyses, suggest the anti-graffiti Ormosil to suppress formation of calcium sulfite hemihydrate (the primary initial product of the reaction of calcium compounds with SO2 and water) on carbonate materials (limestone and lime mortar). In case of the granite, brick and cement mortar, Ormosil has a negligible influence on the SO2 capture. While no sulfite formation was detected by DR-FTIR, gypsum is inferred to form due to metal oxides and minority compounds catalysed oxidation of sulfite to sulfate. In case of brick, this understanding finds support from SEM images as well as EDX. A priori presence of gypsum in hydrated cement mortars prevents positive identification by SEM. However, support for sulfur accumulation in hydrated cement mortar is provided by means of EDX. In case of a second anti-graffiti considered, Protectosil, no influence of the anti-graffiti treatment on the SO2 uptake of any of the building materials was observed.
The elimination of spray paint using traditional (chemical and mechanical) methods inevitably entails altering surface characteristics. Hence, the impact and deterioration caused by graffiti in ...heritage buildings and monuments have led to the development and application of preventive systems in the form of antigraffiti coatings (which prevent paint from seeping into the pores of the surface material and facilitate cleaning). The effectiveness of two of these treatments, a commercial product (fluoroalkyl siloxane, protectosil, marketed by Degussa) and a hybrid organic-inorganic material (Ormosil), was evaluated in five construction materials (limestone, granite, cement mortar, lime mortar and brick), in terms of their penetration into the substrate. A number of techniques were used to determine the penetration depth (SEM/EDX, micro-Raman and LIBS), because a comparative analysis showed that none was universally valid for all types of treatments. The results show that the presence of the coating on the surface of less porous materials only ensures effective cleaning when the surface is fairly smooth. In granite, for instance, the CF
3 terminals in the fluorinated treatment hinder spray paint bonding more effectively than Ormosil, but not efficiently enough to ensure complete removal of the paint from granite surfaces.
Early November 1597. After an intense combat with four enemy ships, San Giacomo di Galizia (also known as Santiago), a just over 1000-ton galleon, enters the Ribadeo harbour in a terrible state, ...where it wrecks. This war vessel had been built in Naples in 1590 and sailed the Mediterranean and the Atlantic until it sank. In late November 2011, during an archaeological survey of the dredge area to improve the navigation of the ports in Galicia, a large ship was found and identified as the San Giacomo, which wrecked 414 years prior to its discovery. Several archaeological campaigns permitted a thorough record of the wreck and the recovery of hundreds of objects which this ship carried on its final journey. These artefacts included ceramics, metalwork, and wood, objects which reflected the activities that occurred on board during its short life. Combining an interdisciplinary approach based on artefacts, documents, and chemical analysis, the aim of this paper is to, on the one hand, attempt to reconstruct the sailing itinerary of the ship over its period of use and, on the other, to discuss how these commodities can help to write new narratives about the activities which occurred on board.
This paper studied in situ, by Micro-Raman spectroscopy, the very early hydration of C3A in the presence and absence of sulphates and with sucrose as an additive. For C3A hydration in the absence of ...gypsum, when carbonation is not avoided, carbonate-AFm phases are formed, but in the presence of gypsum, hydroxi-AFm are the main phases. Ettringite is the AFm stable phase developed initially at 70 min of hydration with gypsum and no monosulphate is formed. In the presence of sucrose, this salt, instead of sulphate, is adsorbed over the surface of the C3A, avoiding its reaction with sulphates until sucrose desorption. Three hours are necessary to lead to ettringite formation. A nucleation poisoning/adsorption surface mechanism is proposed for added sucrose systems.
The spectroscopy technique of Micro-Raman is an appropriate method to investigate the microscopic structure of internally heterogeneous (i.e., composed of multiple layers) agro-food products. The ...effects of applying magnetic fields (magneto-priming technique) and imbibition on the chemical makeup of Triticale seed were studied, particularly in its pericarp, germ and endosperm parts, with the help of Micro-Raman. In light of the results obtained, the magneto-primed seeds soaked in water presented a greater number of chemical compounds than the control seeds, although those treatments were not as effective as the ones with only magneto-priming. The effects of the magneto-priming treatment were especially noticeable in the endosperm due to the large number of chemical compounds identified. The seed composition differences among treatments showed that the use of Micro-Raman jointly with magneto-priming is an appropriate method to obtain and analyse information of the key components of Triticale seeds, notably regarding their pericarp and endosperm.
Activated carbon mining waste influences the formation of hydrated phases, their saturation indexes and mineral stability fields during pozzolanic reactions. The behavior of these reactions is ...predicted in this study by examining the influence of carbon waste at 600°C over 2h, by means of a thermodynamic model running on a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations (PHREEQC program: pH-REdox-Equilibrium in Program C). Experimental analysis of the solid phases shows early formation of monosulfoaluminate hydrate, C–S–H phases and subsequent precipitation of laminar minerals, tetracalcium aluminate hydrate, layered double hydroxide compounds (phyllosilicate/carbonate) (LDH) and stratlingite. Monosulfoaluminate hydrate was formed on day one of the reaction for samples with activated coal mining waste. The thermodynamic calculations confirmed the experimental observations.
•The carbon waste shows phyllosilicates, quartz, calcite, dolomite and feldspars.•According to the kinetic parameter values, the reaction rate was 10−3h−1.•Carbonate and sulfate of low crystallinity have been formed in Portlandite solution.
A glassy material similar to fulgurites (fusion of the soil which has been struck by lightning) was prepared by continuous wave (CW) CO2 laser (λ = 10.6 μm) ablation of lime–pozzolan mortar at ...medium‐vacuum conditions and atmospheric pressure. In all the irradiated samples, the determined surface temperature is higher than the melting temperature of mortar (1556 K), so the surface is melted and converted into an amorphous glassy when cooled. The samples were studied combining laser‐induced breakdown spectroscopy (LIBS) and Raman spectroscopy. The emission induced by the CW CO2 laser is mainly due to electronic relaxation of Na, K, Si, Si+, Ca, O, N, and CaOH species along with an intense continuum due to blackbody emission. The emission induced on both natural and produced fulgurite is mostly due to electronic relaxation of Ca, Ca+, Si, Si+, Si2+, Si3+, H, Na, K, Mg, N, O, CaOH, and OH species with different relative intensities in some of them. Raman spectra show that the glassy formed material is similar to natural fulgurites, with the main difference arising from portlandite formed over the surface of the lime–pozzolan mortar. As the laser power increases, less density SiO2 glass is formed with more Q4 and Q1 units present.
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