Influencia de la ceniza de bagazo de caña sin tratamiento en la microestructura y propiedades mecánicas de morteros

This study investigated the effects of the addition of untreated sugarcane bagasse ash (UtSCBA) on the microstructural and mechanical properties of mortars. The SCBA was sieved for only five minutes through a No. 200 ASTM mesh, and fully characterized by chemical composition analysis, laser ray diffraction, the physical absorption of gas, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Mortar mixtures with 0, 10 and 20% UtSCBA as cement replacement and a constant 0.63 water/cementitious material ratio were prepared. Fresh properties of the mortars were obtained. The microstructural characteristics of the mortars at 1, 7, 28, 90 and 600 days were evaluated by SEM and XRD. The compressive strengths of the mortars at the same ages were then obtained. The results show that the addition of 10 and 20% UtSCBA caused a slight decrease in workability of the mortars but improved their microstructure, increasing the long-term compressive strength.En esta investigación se evaluó el efecto de la adición de ceniza de bagazo de caña (CBC) en la microestructura de morteros. La CBC fue tamizada durante 5 minutos a través de la malla No. 200 ASTM y evaluada mediante pruebas de análisis químico, difracción láser, absorción física de gases, Microscopia Electrónica de Barrido (MEB) y Difracción de Rayos X (DRX). Se elaboraron mezclas de mortero con 0, 10 y 20% de CBC como sustituto parcial del cemento manteniendo una relación agua/materiales-cementantes de 0.63. Se realizaron pruebas en estado fresco y pruebas de caracterización microestructural a través de MEB y DRX y de resistencia a la compresión a edades de 1, 7, 28, 90 y 600 días. Los resultados muestran que la adición de 10 y 20% de CBC decrementa la trabajabilidad de los morteros, sin embargo, mejora su microestructura e incrementa su resistencia a la compresión a edades tardías

The influence of untreated sugarcane bagasse ash on the microstructural and mechanical properties of mortars

ABSTRACT: This study investigated the effects of the addition of untreated sugarcane bagasse ash (UtSCBA) on the microstructural and mechanical properties of mortars. The SCBA was sieved for only five minutes through a No. 200 ASTM mesh, and fully characterized by chemical composition analysis, laser ray diffraction, the physical absorption of gas, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Mortar mixtures with 0, 10 and 20% UtSCBA as cement replacement and a constant 0.63 water/cementitious material ratio were prepared. Fresh properties of the mortars were obtained. The microstructural characteristics of the mortars at 1, 7, 28, 90 and 600 days were evaluated by SEM and XRD. The compressive strengths of the mortars at the same ages were then obtained. The results show that the addition of 10 and 20% UtSCBA caused a slight decrease in workability of the mortars but improved their microstructure, increasing the long-term compressive strength. Keywords: Pozzolan, waste treatment, mortar, hydration products, compressive strength RESUMEN: Influencia de la ceniza de bagazo de caña sin tratamiento en la microestructura y propiedades mecánicas de morteros. En esta investigación se evaluó el efecto de la adición de ceniza de bagazo de caña (CBC) en la microestructura de morteros. La CBC fue tamizada durante 5 minutos a través de la malla No. 200 ASTM y evaluada mediante pruebas de análisis químico, difracción láser, absorción física de gases, Microscopia Electrónica de Barrido (MEB) y Difracción de Rayos X (DRX). Se elaboraron mezclas de mortero con 0, 10 y 20% de CBC como sustituto parcial del cemento manteniendo una relación agua/materiales-cementantes de 0.63. Se realizaron pruebas en estado fresco y pruebas de caracterización microestructural a través de MEB y DRX y de resistencia a la compresión a edades de 1, 7, 28, 90 y 600 días. Los resultados muestran que la adición de 10 y 20% de CBC decrementa la trabajabilidad de los morteros, sin embargo, mejora su microestructura e incrementa su resistencia a la compresión a edades tardías. Palabras clave: Puzolana, Tratamiento de residuos, Mortero, Productos de hidratación, Resistencia a la compresió

A statistical approximation of common Roman ceramics from the Isturgi deposits (Andújar, Andalusia)

Common ceramics constitute a very abundant material in the archaeological record. This study focuses on analyzing and statistically interpreting, from the perspective of archaeological material culture, the features of Roman coarse-ware ceramics from the Isturgi deposits (Andújar, Andalusia). The main goal of this research was to study ceramics from an archaeological perspective with reference to quantitative and qualitative aspects. The fragments of pottery belong to three essential types - kitchenware, tableware, and pottery for storage and transportation - and have different characteristics. The data set consists of 3,626 fragments of ceramics of Roman origin, divided in three clearly differentiated groups: 1) common calcareous ceramics, b) oxidized kitchen ceramics, and 3) reduced kitchen ceramics, having a very different quantity of fragments (1,635; 1,714; and 277, respectively) distributed in 16 excavation zones. The analysis of the information has been carried out on the basis of univariate methods, analysis of correlation and regression, analysis of the variance (ANOVA) and multivariate factorial analysis (Factorial Analysis with Varimax Rotation mainly). In this form it is possible to characterize ceramics on the basis of whether they were fired in an oxidizing or a reducing atmosphere

Analyzing the social factors that influence willingness to pay for the management of invasive alien species under two different strategies: eradication and prevention

This an accepted author's manuscript (AAM) version of an article published in Environmental Management, 48 (2011): 418-43

Effects of scandium composition on the structural, electronic, and thermodynamic properties of SCxY1-x metallic alloys

The aim of this work is to analyse the compositional dependence of the structural, electronic and thermodynamic properties of alloys. Density functional calculations have been carried out to reveal compositional dependence of the structural, electronic and thermodynamic properties of alloys. The lattice constants of the binary compounds are in fairly good agreement with the available experimental data. The variation of calculated lattice constant with scandium concentration is almost linear, and shows a slight deviation from Vegards law. The effect of scandium composition on bulk modulus gives nonlinear dependence on concentration x. A small deviation of the bulk modulus from linear concentration dependence was observed. The metallic nature of binary precursor compounds ScP and YP was confirmed. Our findings indicate that the alloys are metallic for 0.25, 0.5, 0.75. The calculated excess mixing enthalpy is positive over the entire scandium composition range. The positive mixing enthalpies indicate meta-stability of the alloys at high temperatures. The effect of temperature on the volume, bulk modulus, Debye temperature and the heat capacity for alloys were analysed using the quasi-harmonic Debye model. Results show that the heat capacity is slightly sensitive to composition as temperature increases

Sobre el consumo de plantas medicinales a nivel popular

Se recogen una serie de muestras vegetales de elevado consumo popular, en Andalucía oriental, que por diversas causas nos han llamado la atención: en unos casos por las dosis recomendadas, en otros por las sorprendentes indicaciones terapéuticas y mismas.A serie of high popular take vegetable simples in West Andalucía, that for different reason they have attracted us: in sorne cases for the dose recommended, in other cases for the surprising therapeutics indications and other for the composition of the sames are picked up

Sobre el consumo de plantas medicinales a nivel popular

A serie of high popular take vegetable simples in West Andalucía, that for different reason they have attracted us: in some cases for the dose recommended, in other cases for the surprising therapeutics indications and composition of the sames are picked up.Se recogen una serie de muestras vegetales de elevado consumo popular, en Andalucía oriental, que por diversas causas nos han llamado la atención: en unos casos por las dosis recomendadas, en otros por las sorprendentes indicaciones terapéuticas y mismas en otros por la composición de las mismas

Adaptive applications to assist students with autism in succeeding in higher education

Abstract. In this demo we discuss a few possible scenarios showing adaptation of presentation and information to assist autistic students in succeeding in higher education. These students not only have specific information need, they are also more concerned about their privacy. We use WiBAF (Within Browser Adaptation Framework) for user modeling and adaptation to give users control over the sharing of their data

Late Variscan, Permo-Carboniferous, Al-K plutonism in the South Portuguese Zone : El Crispinejo cordierite-bearing granite

The El Crispinejo granite forms part of a small, but distinctive late intrusive suite of cordierite-bearing peraluminous granites in the South Portuguese Zone (SPZ). This granite has the best outcrop relationships of the suite. It cross-cuts different members of the Sierra Norte Batholith of the SPZ and the Carboniferous Volcano-Sedimentary Complex of the Iberian Pyrite Belt, producing contact metamorphism. This late pluton has a high K content which results in a contrasting geophysical response (K-Th-U) with respect to the surrounding trondhjemitic granitoids of the TTG suite of the Sierra Norte Batholith. A concordant monazite-zircon U-Pb ID-TIMS age of 300.5 +0.5/-1.5Ma demonstrates Permo-Carboniferous age for this late Variscan magmatic event. The granite is associated with a series of ore showings (F-Pb-Zn and Sn-W) which are completely different from the nearby, massive sulphide and manganese ore deposits of the Iberian Pyrite Belt, indicating the unique character of this intrusion