Restauración y rehabilitación de edificios y bioconstrucción con morteros ligeros aditivados con fibras vegetales

Abstract

Abstract Incorporating plant-based aggregates into concretes is a challenge because the setting of binders does not appear to be optimal. As they are organic materials, it is also common to find morphological, chromatic- or microbiological pathologies if the construction rhythm is not adapted to the drying behavior of the material. In fact, we have found that it is advisable to wait at least 10 weeks before applying a render on a wall-type material, so as not to hinder the setting of the mass concrete and avoid deterioration of the hemp concrete or the render or an excessive color change. Furthermore, the deterioration of the plaster is conditioned by the lime used in its mixing and the type of binder used in the formulation of vegetable concrete as well as the density of the material. On the other hand, this Thesis evolves favorable experiences, carried out with chemical and non-chemical pretreatments of hemp aggregates that have led to higher mechanical performances of hemp concretes. Our research identifies whether the wet anaerobic preservation of chopped and packed hemp stalk directly in the field constitutes a feasible and sustainable method of improving the performance of different hemp concretes against the same freshly harvested chopped and preserved material, since this preservation induces changes in the structural polymers of the plant. The method is applied to different formulations, bonded with earth stabilized with lime or clay geopolymers. Most of the results show us some new strategies to take full advantage of the potential of thermal and mechanical characteristics of hemp concretes, save water in the mix and use higher proportions of vegetable aggregates than those usually achieved with hemp-lime. The research also highlights the fact that water vapor permeability decreases in formulations mixed with wet preserved hemp and that the porosity of test specimens made with fresh hemp tend slightly towards larger pore radiuses. The accessible porosity of the formulations agglutinated with clay geopolymers, which contain aggregates of the entire stem and are in a range of hemp concretes with greater utility for structural functions, was found to be analogous with different hemp-lime concretes in the literature, although it does not reach the maximum range of results in this field.