The search for electroceramic materials with enhanced ferro-pyro-piezoelectric properties and revealing the perovskite type structure has been the objective of a significant number of manuscripts reported in the literature. This has been usually carried out by proposing the synthesis and processing of new compounds and solid solution series. In this work, several methods to obtain ferro-pyro-piezoelectric families of materials featuring the well-known ABO3 perovskite structure (or related) such as BaTiO3, Ba1–xCaxTi1–yZryO3, (Bi0.5Na0.5)TiO3, (K0.5Na0.5)NbO3 and their solid solutions with different cations either in the A or B positions, are presented. For this kind of materials, the challenge for obtaining a single phase compound with a specific grain size and morphology and, most importantly, with the adequate stoichiometry, will also be discussed. The results reviewed herein will be discussed in terms of the tendency of working with softer conditions, i.e., lower temperature and shorter reaction times, also referred to as soft-chemistry.

The reinforcement of soils is the technique that geotechnical engineers currently use to improve the shear strength and bearing capacity parameters, especially when the land available for the execution of a project is not able to withstand the structural loads to which it is subjected. One of the techniques, used for this purpose since ancient times, is the incorporation of fibers into the soil matrix; however, great interest in its study has only begun in the last two, mainly because it constitutes a low-cost and environmentally friendly alternative. In this paper, a brief bibliographic review is presented on seven of the natural fibers that are currently used in order to improve the mechanical behavior of expansive clay soils (bamboo, jute, coco, palm, sugar cane bagasse, rise husk, and sawdust). It can be concluded that in many cases, the addition of certain amounts of natural fibers increases the parameters of resistance to the cutting of soils.

4A Zeolite was synthesized using rice husk ash (RHA) as a raw material in a microwaveassisted hydrothermal synthesis. Two new procedures were proposed: procedure A, using RHA as the raw material, and procedure B, using the depolymerized RHA. Both procedures were performed using microwave-assisted hydrothermal synthesis, and neither synthesis required an aging time. Crystallinities of over 90 and 80% were reached at 100 °C after 30 min of microwave heating for procedures A and B, respectively. The obtained zeolites were used as warm mix asphalt additives, and the performance of the zeolite obtained from procedure A was better. Additionally, the zeolite obtained from procedure A and commercial silane were used separately as asphaltaggregate adhesion promoter. An increase in the adhesion percentage from 30% of a blank sample to 94% was observed.

This communication reports the microwave-assisted hydrothermal synthesis of the x = 0.1 member of the solid solution Ba 1-x Ca x TiO 3 (BCT) materials, its structural and microstructural characterisation and the piezoelectric properties. Using this novel -'fast chemistry'synthetic procedure, this material can be obtained in much shorter periods of time in comparison with conventional solid-state methodologies: just a few minutes instead of days. Under microwave irradiation in aqueous basic solutions, the material produced is a polycrystalline and nanosized powder which was processed as a ceramic disc in order to measure piezoelectric properties. A maximum d 33 value of 118 pC/N is obtained for this sample with a poling electric field of 1.5 KV mm −1 , a value similar to those reported for conventionally made BCT materials.