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The effective re-use of industrial by-products calls for an understanding of their chemical, mineralogical and physical characteristics. The by-product used in this study was coated paper industry sludge from a plant whose sole prime material is recycled paper. Due to its high organic and calcium carbonate content and the presence of several clayey materials such as talc and kaolinite, incineration conditions had a significant effect on the mineralogy of such sludge. The present study examined the impact of such conditions on the pozzolanic properties of coated paper sludge. Several temperature intervals ranging from 600 to 750 ºC were studied to determine the conditions yielding the most promising pozzolanic properties.

The present article discusses the effect of paper sludge additions, calcined at 700 ºC for two hours, on cement paste pore structure and mechanical strength. Both total and capillary porosity were observed to depend on the percentage of calcined sludge added to the cementitious matrix. While a 10% addition induced values for both slightly higher than the control, adding 20% prompted the opposite result, reducing porosity values with respect to the control. Substantial refinement was observed, with a rise in pores smaller than 0.01 μm (gel pores) when the calcined sludge was added. Such refinement was greater at the higher percentage of sludge. After approximately 15 days, strength was lower in both the additioned pastes compared to the control. A high correlation (R2≥0.939) was found between total porosity and compressive strength for both percentages studied.

Mineralogically, the paper mill sludge consists essentially of calcite, kaolinite, talc and other philosilicates (illite, chlorite). When such sludge is subjected to controlled thermal treatment, its kaolinite component may be transformed into metakaolin, yielding a product with high pozzolanic reactivity. This study was designed to analyze a number of scientific questions around the production of pozzolanic additions via controlled thermal activation of paper mill sludge and to evaluate the performance of such additions when included in a cement matrix. The findings show that paper mill waste activation is optimal when the sludge is calcined for 2 hours at 700 ºC in the 700-800 ºC interval. A comparative study between the cement made with the new addition and a commercial cement (CEM I-42.5R) used as a reference led to highlight the scientific and technical viability of this waste as a cementing secondary material.

The present study addresses variations in the calcination temperature (600-750 ºC) and kiln time (two to five hours) applied to activate coated paper waste and their effect on the rheological, physical and mechanical behaviour of cement matrices containing these active additions. The results obtained showed that the conditions under which kaolinite was activated had a direct effect on the subsequent behaviour of the calcined products. At activating temperatures of over 700 ºC, pozzolanic activity and mechanical strength were observed to be lower, setting time shorter and the mortar less workable.

El artículo analiza la mención de un dibujo a pluma atribuido a Van Eyck en un inventario post-mortem fechado en 1452, y realizado en Valencia. Los bienes del elenco pertenecieron a Andreu Garcia, presbítero beneficiado en la catedral de la ciudad bien conocido por la historiografía en virtud de sus importantes vínculos con los artistas más señalados que trabajaron en la urbe durante la primera mitad del siglo XV. La noticia da pie a una nueva revisión del cada vez más improbable paso de Van Eyck por los territorios de la Corona de Aragón, así como de la huella temprana de su pintura en estos lugares, habida cuenta de que, como revela el documento, el primer propietario del dibujo fue Berenguer Mateu, pintor hermano de Jaume Mateu, uno de los mejores representantes de la segunda generación de pintores del Gótico Internacional en la capital del Reino.

Los temas griegos en -ōs/-eu, -ēs/-eu, -ā/ei deben interpretarse como derivados de antiguos temas indoeuropeos en laringal.