Carbonation of concrete with construction and demolition waste based recycled aggregates and cement with recycled content

Durability is a major concern in concrete (particularly recycled concrete) structures exposed to carbonation-induced corrosion, given the social, economic, environmental and safety implications involved. This article explores carbonation performance in concrete with 25% or 50% mixed recycled construction and demolition waste aggregate, alone or in conjunction with cement containing 25% fired clay construction and demolition waste. Irrespective of cement type, the mean carbonation depth was slightly greater in materials with 25% or 50% recycled aggregate than in concretes with 100% natural aggregate, although the difference was not statistically significant for the 25% replacement ratio. In all the concretes studied, the carbonation coefficient was below the 4 mm/yr0.5 indicative of good quality. Based on the prediction model proposed in Spain’s concrete code, reinforcement passivity was guaranteed in all these types of concrete when exposed to class XC1 to XC4 carbonation environments for substantially longer than their 100 year design service life.This study was funded under research projects BIA 2013-48876-C3-1-R, BIA2013-48876-C3-2-R and BIA2016-76643-C3-1-R awarded by the Ministry of Science and Innovation and grant GR 18122 awarded to the MATERIA Research Group by the Regional Government of Extremadura and the European Regional Development Fund, ERDF. In 2016 University of Extremadura teaching and research personnel benefitted from a mobility grant (MOV15A029) awarded by the Regional Government of Extremadura and in 2018 from a José Castillejo (CAS17/00313) scholarship granted by the Spanish Ministry of Education, Culture and Sport. Philip Van den Heede is since October 2017 a postdoctoral fellow of the Research Foundation—Flanders (FWO) (project number 3E013917) and acknowledges its support.Peer reviewe

Espais naturals al País Valencià: Una nova categoria de gestió. Breu exposició sobre el Decret 109/1998 de 29 de juliol, del Govern valencià

El medi natural del País Valencià es caracteritza per la seua antropització, per la tradicional convivència de l'acció humana amb unes condicions naturals típicament mediterrànies. Fins aquest moment, l'habitual política de protecció dels espais naturals venia exercint-se com una responsabilitat fonamentalment autonòmica en què els municipis sols tenien un paper marginal o, com a molt, subsidiari. El Decret del Govern valencià 109/1998 permet als ajuntaments d'aquesta Comunitat accedir als seients davanters en aquesta matèria, però allò que podria ser positiu en tant a la iniciativa de protecció no ha de significar una desordenada formulació de mesures de gestió, ús i regulació dels paratges. Així doncs, correspon a l'Administració ambiental valenciana un paper permanent de tutela i ordenació que no nega, gens ni mica, les essencials funcions locals conferides en aquest tema. A més, s'analitzen alguns defectes jurídics formals que poden sorgir en l'aplicació de l'esmentat Decret i es proposa que reste un menor marge discrecional a l'administració autonòmica.El medio natural del País Valenciano se caracteriza por su antropización, por la convivencia tradicional de la acción humana con unas condiciones naturales típicamente mediterráneas. Hasta este momento la tradicional política de protección de los espacios naturales venía ejerciéndose como una responsabilidad fundamentalmente autonómica en la cual los municipios sólo tenían un papel marginal o como mucho subsidiario. El Decreto del Gobierno Valenciano 109/1998 permite a los ayuntamientos de esta Comunidad tomar los asientos delanteros en esta materia, pero lo que puede ser positivo en cuanto a iniciativa de protección no debe significar una desordenada formulación de medidas de gestión, uso y regulación de los parajes. Corresponde así a la Administración ambiental valenciana un permanente papel de tutela y ordenación que en nada ahoga las esenciales funciones locales conferidas en este asunto. Se analizan algunos defectos jurídico formales que pueden surgir ante la aplicación del mencionado Decreto y se propone que deje un menor margen discreccional a la Administración autonómica.The natural environment of the Valencia Land is characterized by its anthropization, i.e. the traditional cohabitation of activity human and the typically Mediterranean natural conditions. Until now, the traditional policy of protecting nature reserves was being implemented mainly as a regional responsibility. Town councils played only a marginal or at best a subsidiary part in this process. The 109/1998 Decree of the Valencia Government allowed town councils to play a leading role in this matter, but something that could be positive for protection initiatives, should not mean a disorderly formulation of the measures for the management, use and regulation of the areas. The Valencia environment administration therefore has a permanent role in supervising and maintaining order, without hindering at all the essential local functions granted in this matter. Some procedural flaws that could arise during the application of the aforementioned Decree are analysed, and a proposal is made that would give the regional government a smaller margin of discretion

The Signature Triality of Majorana-Weyl Spacetimes

Higher dimensional Majorana-Weyl spacetimes present space-time dualities which are induced by the Spin(8) triality automorphisms. Different signature versions of theories such as 10-dimensional SYM's, superstrings, five-branes, F-theory, are shown to be interconnected via the S_3 permutation group. Bilinear and trilinear invariants under space-time triality are introduced and their possible relevance in building models possessing a space-versus-time exchange symmetry is discussed. Moreover the Cartan's ``vector/chiral spinor/antichiral spinor" triality of SO(8) and SO(4,4) is analyzed in detail and explicit formulas are produced in a Majorana-Weyl basis. This paper is the extended version of hep-th/9907148.Comment: 28 pages, LaTex. Extended version of hep-th/990714

Análisis bibliométrico de las publicaciones científicas españolas en la categoría Construction & Building Technology de la base de datos Web of Science (1997-2008)

En este trabajo se analizan las publicaciones procedentes de instituciones españolas recogidas en las revistas de la categoría Construction & Building Technology de la base de datos Web of Science para el periodo 1997-2008. El número de revistas incluidas es de 35 y el número de artículos publicados ha sido de 760 (Article o Review). Se ha realizado una evaluación bibliométrica con dos nuevos parámetros: Factor de Impacto Ponderado y Factor de Impacto Relativo; asimismo se incluyen el número de citas y el número de documentos a nivel institucional. Entre los centros con una mayor producción científica destaca, como era de prever, el Instituto de Ciencias de la Construcción Eduardo Torroja (CSIC), mientras que atendiendo al Factor de Impacto Ponderado ocupa el primer lugar la Universidad de Vigo. Por otro lado, sólo dos revistas Cement and Concrete Research y Materiales de Construcción aglutinan el 45.26% de toda la producción científica española, con 172 trabajos cada una de ellas. En cuanto a la colaboración internacional, destacan países como Inglaterra, México, Estados Unidos, Italia, Argentina y Franci

Exactly solvable mixed-spin Ising-Heisenberg diamond chain with the biquadratic interactions and single-ion anisotropy

An exactly solvable variant of mixed spin-(1/2,1) Ising-Heisenberg diamond chain is considered. Vertical spin-1 dimers are taken as quantum ones with Heisenberg bilinear and biquadratic interactions and with single-ion anisotropy, while all interactions between spin-1 and spin-1/2 residing on the intermediate sites are taken in the Ising form. The detailed analysis of the $T=0$ ground state phase diagram is presented. The phase diagrams have shown to be rather rich, demonstrating large variety of ground states: saturated one, three ferrimagnetic with magnetization equal to 3/5 and another four ferrimagnetic ground states with magnetization equal to 1/5. There are also two frustrated macroscopically degenerated ground states which could exist at zero magnetic filed. Solving the model exactly within classical transfer-matrix formalism we obtain an exact expressions for all thermodynamic function of the system. The thermodynamic properties of the model have been described exactly by exact calculation of partition function within the direct classical transfer-matrix formalism, the entries of transfer matrix, in their turn, contain the information about quantum states of vertical spin-1 XXZ dimer (eigenvalues of local hamiltonian for vertical link).Comment: 14 pages, 9 figure