Análise do desempenho de argamassas produzidas com cinzas de biomassa em diferentes períodos de estocagem

Abstract

The application of agro-industrial waste, such as rice husk ash (RHA), eucalyptus chip ash (ECA) and sugarcane bagasse ash (SCBA), in cement products, improves management, reduces the volume and contributes to the final disposal of these discarded materials in the environment. Therefore, for these wastes to be included and addressed in civil construction, it is necessary to evaluate the physical, physical and mechanical performance requirements, validating them as supplementary cementitious materials (SCM). To this end, they began to use this biomass ash in partial replacements of Portland cement in modified mortars, three traits Tmin, Tmea and Tmax were produced, using respectively the mixtures of biomass ash, Cmin, Cmea and Cmax, and for comparative purposes, a reference trace (Tref) free of substitutions was produced. Preliminarily, the characterizations of the ash and biomass mixtures were carried out through tests of granulometric composition, fineness, humidity, fire loss, particle density and Chapelle pozzolanic activity index. Furthermore, the amount of water required to supply the masses of normal consistency and the setting time interval for each of the cementitious masses modified with the biomass mixtures were determined. Aiming to analyze the influence of the incorporation of the mixtures in the modified mortars, the flexural tensile strength and simple seam resistance were evaluated at 7, 14, 28 and 56 days of curing. Even so, in the long-lasting state, water absorption by capillarity was determined at 28 days. The results showed that the modification trait can be chosen as the ideal trait for the development of an eco-efficient mortar. Finally, the storage time of the ideal mixture of the modified mortar was validated, which replaces Portland cement by 26.75% with biomass ash. To this end, the performance of the mortar was analyzed by dosing and molding the test specimens every 30 days, carrying out flow table tests, simple elasticity resistance, flexural tensile strength, dimensional variation, and tensile adhesion resistance, permeability and scanning electron microscopy. The ideal mix performed well up to 60 days of storage, but after 90 days of storage, both the reference mortar and the modified mortar had their properties compromised.