Agroindustrial residues in fiber cement composites for civil construction: using mineral additions to improve fiber-matrix interface

Abstract

The use of industrial by-products can become an important and significant factor for the development of the sector of civil construction in Brazil. This project proposes the study of a new cementitious material reinforced with chopped macro sisal fibers for the production of construction elements. The main objective of the post-doctorate study is the optimization of the fiber-matrix interface using mineral additions (sugar cane waste ashes and/or corn straw ashes) with the cement matrix. In the first stage, the pozzolanic activity of the mineral additions will be assessed for the preparation of a cementitious matrix free of calcium hydroxide, in order to increase the mechanical strength of the matrix and to contribute with the durability of the vegetable fibers in the composite. The composites will be elaborated using the slurry dewatering process followed by pressing and cured in saturated CO2 atmosphere. The composites will be subjected to physical and mechanical tests to evaluate the tensile strength under bending load before and after exposition to the accelerated aging cycles. The microstructural characteristics, pores distribution and densification of the fiber-matrix transition zone will be evaluated by the scanning electron microscopy (SEM), nanoindentation and X -ray tomography. The results obtained with the improved fiber-matrix adhesion will enable the development of a new non-conventional and technically more efficient and sustainable material for the civil construction, especially in the production of prefabricated elements. (AU)