Estudio de la velocidad de corrosión de aceros embebidos en morteros de cemento sustituidos con residuo de catalizador de craqueo catalítico (FC3R)

This paper reports on a study of the corrosion levels in steel bars embedded in mortars made with a blend of Portland cement and (0-20%) spent fluid catalytic cracking catalyst residue (FC3R), with a variable (0.3-0.7) water/binder (w/b) ratio. The specimens were stored in the following conditions: relative humidity of 40, 80 or 100% and CO2 concentrations of 5 and 100%. The steel corrosion rate was measured with polarization resistance techniques. In the absence of aggressive agents, the steel was found to remain duly passivated in mortars with an FC3R content of up to 15% under all the conditions of relative humidity tested. The reinforcement corrosion level in mortars with a w/b ratio of 0.3 and 15% FC3R subjected to accelerated carbonation was similar to the level observed in the unblended Portland cement control mortar.En este trabajo se ha estudiado el nivel de corrosión de barras de acero embebidas en morteros de cemento Portland con relación agua/material cementante (a/mc) variable (0,3-0,7), en los que parte del cemento (0-20%) se sustituyó por catalizador de craqueo usado (FC3R). Las condiciones de conservación de las probetas elaboradas fueron las siguientes: distintas humedades relativas (40, 80 y 100%) y dos concentraciones de CO2 (5 y 100%). La velocidad de corrosión de los aceros se midió mediante la técnica de resistencia de polarización. Se ha podido determinar que, bajo las distintas condiciones de humedad relativa y ausencia de agresivo, los aceros se mantuvieron correctamente pasivados en los morteros con contenidos de FC3R de hasta el 15%. El nivel de corrosión que presenta el refuerzo embebidos en morteros con sustitución de un 15% de cemento por FC3R y relación a/mc 0,3, al ser sometidos a un proceso de carbonatación acelerada, era muy similar al mostrado por el mortero patrón, sin FC3R

Outstanding aspects on the use of spent FCC catalyst in binders

4 pages, 3 fiures, 7 tables.-- En: 1st Spanish National Conference on Advances in Materials Recycling and Eco – Energy Madrid, 12-13 November 2009.-- Editors: F. A. López, F. Puertas, F. J. Alguacil and A. Guerrero.FCC is a waste material from petrochemical plants which has interesting properties for preparing binders. FCC is lightly grey in color, and white FCC-portland cements with L*≥85 can be prepared. FCC reactivity is enhanced by grinding and it is attributed to pozzolanic reaction towards lime. Stratlingite is the main hydrated product from pozzolanic reaction, and CSH and CAH are also formed. Reactivity of FCC is high, and low curing temperature does not affect this contribution to strength in hardened mixtures. Additionally, high strength concrete can be easily prepared, and compressive strength greater 100MPa can be reached. Mixtures with low w/b ratio showed good behaviour in carbonation tests.Authors thank to Ministerio de Ciencia y Tecnología of Spain and FEDER the financial support of MAT 2001-2694 and BIA 2004-0052 projects.Peer reviewe

Genome-wide analysis of the H3K27me3 epigenome and transcriptome in brassica rapa

Background Genome-wide maps of histone modifications have been obtained for several plant species. However, most studies focus on model systems and do not enforce FAIR data management principles. Here we study the H3K27me3 epigenome and associated transcriptome of Brassica rapa, an important vegetable cultivated worldwide. Findings We performed H3K27me3 chromatin immunoprecipitation followed by high-throughput sequencing and transcriptomic analysis by 3′-end RNA sequencing from B. rapa leaves and inflorescences. To analyze these data we developed a Reproducible Epigenomic Analysis pipeline using Galaxy and Jupyter, packaged into Docker images to facilitate transparency and reuse. We found that H3K27me3 covers roughly one-third of all B. rapa protein-coding genes and its presence correlates with low transcript levels. The comparative analysis between leaves and inflorescences suggested that the expression of various floral regulatory genes during development depends on H3K27me3. To demonstrate the importance of H3K27me3 for B. rapa development, we characterized a mutant line deficient in the H3K27 methyltransferase activity. We found that braA.clf mutant plants presented pleiotropic alterations, e.g., curly leaves due to increased expression and reduced H3K27me3 levels at AGAMOUS-like loci. Conclusions We characterized the epigenetic mark H3K27me3 at genome-wide levels and provide genetic evidence for its relevance in B. rapa development. Our work reveals the epigenomic landscape of H3K27me3 in B. rapa and provides novel genomics datasets and bioinformatics analytical resources. We anticipate that this work will lead the way to further epigenomic studies in the complex genome of Brassica crops

Laboratory evaluation of the compatibility of a new attractant contaminant device ciontaining Metarhizium anisopliae with Ceratitis capitata sterile males

[EN] Laboratory experiments were conducted to evaluate the compatibility of using the entomopathogenic fungus Metarhizium anisopliae, to be dispensed in a new attractant contaminant device (ACD), jointly with sterilized Ceratitis capitata males, as an integrated approach to control this major pest. The exposure of sterile Vienna 8 (V8) strain and wild type (WT) males to the contaminating part (infective dish) of the ACD showed similar susceptibility levels to the fungal strain (LT50 value of 4.52 and 4.72 days, respectively). Sterile V8 males were significantly less attracted to the infective dish (18.4%) than WT males (28.5%). As the success of Sterile Insect Technique (SIT) heavily relies on the mating success of sterile males in the field, mating performance of infected males was assessed. Around 85% of the females were mated, independently of the male strain and treatment (fungus-treated or untreated males) indicating that mating performance was unaffected by the fungus under laboratory conditions. Females showed a greater tendency to remate if previously mated to fungus-treated males, either V8 or WT. Our data suggest that this M. anisopliae based-ACD does not impair the performance of C. capitata sterile males and, therefore, it could be used combined with area wide SIT-based programs, providing that these results are validated in field conditions. The implications of this combined strategy to control C. capitata are discussed. (C) 2014 Elsevier Inc. All rights reserved.This work was partially supported by the "Comision Interministerial de Ciencia y Tecnologia" (CICYT, Spain) (Grant: AGL2006-13346-C02-02).San Andrés Aura, V.; Ayala Mingol, I.; Abad Payá, MDC.; Primo Millo, J.; Casteñera, P.; Moya Sanz, MDP. (2014). Laboratory evaluation of the compatibility of a new attractant contaminant device ciontaining Metarhizium anisopliae with Ceratitis capitata sterile males. Biological Control. 72:54-61. https://doi.org/10.1016/j.biocontrol.2014.02.007S54617

Study on binary and ternary systems with cement, hydrated lime and fly ash: thermogravimetric analysis, mechanical analysis and durability behaviour

The use of high percentages of substitution of Portland cement by pozzolans can provoke the total consumption of portlandite. The present research proposes the study of ternary systems of Portland cement (PC), fly ash (FA), and hydrated lime (CH). After 180 days of curing, the mortar with 50% substitution of PC by FA obtained 65.9 MPa versus the mortars with an addition of 20% of CH and control mortar (100 PC) that obtained 69.9 MPa and 76.7 MPa respectively: this behavior is very positive value considering that tested FA containing mortars had a 50% of Portland cement. Regarding the effect of the amount of extra hydrated lime on durability issues, the evolution against carbonation of PC-FA and PC-CH-FA mortars was studied: the reduction of carbonation velocity was around a 37% for the mortar with CH respect the PC-FA mortar

Efecto de la adición de ceniza de lodo de depuradora (CLD) en las propiedades mecánicas y niveles de corrosión de las armaduras embebidas en morteros de cemento Portland

The article describes a study conducted to determinecorrosion in reinforcement embedded in Portland cement(PC) mortars with different percentages of sewage sludgeash (SSA) admixtures. The polarization resistancetechnique was used to determine the steel corrosion rate(Icorr) in the test specimens. The samples were subjectedto different environmental conditions and aggressiveagents: 100% relative humidity (RH), accelerated carbonationat 70% RH and seawater immersion. Portlandcement was partially substituted for SSA in the mixes atrates of 0, 10, 20, 30 and 60% (by mass) to make thedifferent mortars. The results show that where cementwas replaced by SSA at rates of up to 10% by mass,mortar corrosion performance was comparable to thebehaviour observed in SSA-free mortars (control mortar:0% SSA). Data for higher rates are also shown. From themechanical standpoint, SSA exhibited moderate pozzolanicactivity and the best performance when SSA wasadded at a rate of 10% to mixes with a water/(binder:PC + SSA) (w/b) ratio of 0.5.Se ha estudiado el nivel de corrosion que presentan lasarmaduras embebidas en morteros fabricados con cementoPortland (CP) con diferentes porcentajes de sustitucion deceniza de lodo de depuradora (CLD). Se ha utilizado la tecnicade la Resistencia a la Polarizacion para determinar lavelocidad de corrosion del acero embebido en las muestrasestudiadas. Las muestras se han sometido a diferentes condicionesambientales y agentes agresivos: 100% de humedadrelativa (HR), carbonatacion acelerada al 70% HR einmersion en agua de mar. Para la fabricacion de los distintosmorteros, el cemento Portland ha sido parcialmente sustituidopor CLD en los siguientes porcentajes en masa: 0,10, 20, 30 y 60%. Los resultados muestran que sustitucionesde cemento por CLD de hasta el 10% en masa no alteranel comportamiento frente a la corrosion de los morterosal compararlos con los morteros libres de CLD (morteroscontrol: 0% de sustitucion de cemento por CLD). Se presentantambien los datos para intervalos de sustitucion masaltos. Desde el punto de vista mecanico, la CLD muestra unamoderada actividad puzolanica, obteniendose el mejor comportamientocuando el porcentaje de sustitucion de CLD porcemento fue del 10% y la mezcla fue formulada con unarelacion agua/(conglomerante: CP + CLD) (a/c) de 0,5

Performance of white portland cement matrixes blended with nanosilica and limestone for architectural applications

Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint feesʺPermission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.”This research evaluates the combination of nanosilica particles and ground limestone as mineral additions for white Portland cement (WPC) matrixes, envisioning architectural applications where the whiteness of the final product is a key feature. The WPC pastes and mortars were fabricated with additions of nanosilica and substitutions of cement by limestone. An experimental campaign was carried out to study the effect of the combination of nanoparticles and mineral additions over the hydration process, whiteness and mechanical performance of the WPC matrices. It was found that nanosilica in combination with limestone is an excellent option as a mineral addition for WPC, since it can improve its properties in the fresh and hardened states without altering the colour of the final product.Tobón, JI.; Mendoza, OA.; Paya Bernabeu, JJ. (2016). Performance of white portland cement matrixes blended with nanosilica and limestone for architectural applications. Advances in Cement Research. 28:606-615. doi:10.1680/jadcr.16.00015S6066152

Microscopy Characterization of Silica-Rich Agrowastes to be used in Cement Binders: Bamboo and Sugarcane Leaves

Agrowastes are produced worldwide in huge quantities and they contain interesting elements for producing inorganic cementing binders, especially silicon. Conversion of agrowastes into ash is an interesting way of yielding raw material used in the manufacture of low-CO2 binders. Silica-rich ashes are preferred for preparing inorganic binders. Sugarcane leaves (Saccharum officinarum, SL) and bamboo leaves (Bambusa vulgaris, BvL and Bambusa gigantea, BgL), and their corresponding ashes (SLA, BvLA, and BgLA), were chosen as case studies. These samples were analyzed by means of optical microscopy, Cryo-scanning electron microscopy (SEM), SEM, and field emission scanning electron microscopy. Spodograms were obtained for BvLA and BgLA, which have high proportions of silicon, but no spodogram was obtained for SLA because of the low silicon content. Different types of phytoliths (specific cells, reservoirs of silica in plants) in the studied leaves were observed. These phytoliths maintained their form after calcination at temperatures in the 350¿850°C range. Owing to the chemical composition of these ashes, they are of interest for use in cements and concrete because of their possible pozzolanic reactivity. However, the presence of significant amounts of K and Cl in the prepared ashes implies a limitation of their applications.The authors thank the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (Projeto CNPq 40174/2013-1) of Brazil for funding the research. The authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia and Materials Department of Universidade Estadual Paulista at Ilha Solteira.Rosello Caselles, J.; Soriano Martínez, L.; Santamarina Siurana, MP.; Akasaki, JL.; Melges, JLP.; Paya Bernabeu, JJ. (2015). Microscopy Characterization of Silica-Rich Agrowastes to be used in Cement Binders: Bamboo and Sugarcane Leaves. 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