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Zirconium titanate materials are proposed for structural components for which fully reacted and relatively large pieces are required. In this work the phase evolution in slip cast compacts constituted by equimolar mixtures of TiO 2 and ZrO 2 stabilized with 3 mol% of Y 2 O 3 at high temperature is studied, to establish the basis to design suitable thermal treatments for ZrO 2 (Y 2 O 3 )-TiO 2 materials. The temperatures at which the processes involved in the reaction sintering occurred were identified by constant heating rate experiments. Phase and microstructure analyses have been performed on specimens treated at the identified temperatures and air quenched. Then the adequate temperature range to get fully reacted and dense materials has been deduced. Materials treated at 1500 • C to 2 h were constituted by Zr 5 Ti 7 O 24 as major phase, a solid solution of TiO 2 and Y 2 O 3 in c-ZrO 2 as secondary phase and a ZrO 2 -TiO 2 -Y 2 O 3 non-stoichiometric compound with pyrochlore structure as minor phase. Pyrochlore was demonstrated to be a metastable phase at 1500 • C.

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This study focuses on the characterization of bottom ash (PCC-BA) and determining the mechanical characteristics of hot mix asphalt (HMA) using PCC-BA and hydrated lime (HL) as filler. Physical and chemical characterization of the bottom ash was carried out to evaluate its eventual reutilization as filler substitute. The materials tested in this study were made using 0%, 25%, 50%, 70% and 100% of PCC-BA combined with HL. HMA mixes were evaluated in terms of their engineering properties, namely: air voids in the mixes, water sensitivity, stiffness modulus, performance in wheel tracking test and fatigue resistance.The results obtained indicate that HMA mixes with a filler blend of 70% PCC-BA and 30% HL fulfil European standards and are suitable for light traffic or small infrastructures. RESUMEN: Empleo de cenizas de fondo de central térmica y cal como filler en mezclas bituminosas.Este estudio se centra en la caracterización de las cenizas de fondo (PCC-BA) y la determinación de las características mecánicas de mezclas bituminosas en caliente (HMA), utilizando cenizas de fondo y la cal hidratada (HL) como filler. Se realizó la caracterización física y química de las cenizas de fondo para evaluar su empleo como sustituto de filler. Las mezclas ensayadas en este estudio se realizaron utilizando 0%, 25%, 50%, 70% y 100% de cenizas de fondo combinadas con cal hidratada. Se evaluaron propiedades ingenieriles de las mezclas bituminosas, tales como los huecos de aire en las mezclas, la sensibilidad al agua, el módulo de rigidez, el ensayo de pista y la resistencia a la fatiga.Los resultados obtenidos indican que las mezclas bituminosas fabricadas con una combinación de filler del 70% de cenizas de fondo y el 30% cal hidratada, cumplen con las normas europeas y son adecuados para su aplicación con tráficos ligeros o en pequeñas infraestructuras.

Zirconium titanate (ZrTiO 4 ), have many attractive properties such as high resistivity, high dielectric constant, high permittivity at microwave frequencies and excellent temperature stability for microwave properties. Zirconium titanate dense materials are proposed for many structural applications, but fully reacted and completely dense pieces are difficult to obtain by conventional routes. In this work, fully dense zirconium 2 titanate materials (∼ 98%) were obtained at lower temperatures (1300-1400 ºC) and short processing time by non-conventional technique; spark plasma-reaction sintering (SPRS). Homogeneous and stable starting powders mixture with the adequate composition was prepared from the raw materials: m-ZrO 2 (∼ 0.3μ m) and anatase-TiO 2 (∼ 40nm). Dense materials were mechanically and microstructural characterized. The fracture strength was measured by biaxial testing, giving values of about 200 MPa.