Autor(a/res): G. C. Cordeiro, T. R. Barroso e R. D. Toledo Filho

Resumo: In this study, the feasibility and effectiveness of a controlled laboratory re-calcination process was evaluated in order to mitigate the negative effects of Sugar Cane Bagasse Ash (SCBA) with high carbon content on hydration and fresh properties of concrete. Measurements of particle size distribution, chemical composition, BET specifc surface area, and pozzolanic activity were realized to characterize the as-received and re-processed SCBA. Moreover, the distinct SCBAs were evaluated based on results of isothermal calorimetry and time of setting by Vicat method in cement-SCBA pastes and compressive strength, Young’s modulus, and water absorption in a 35-MPa concrete. The results showed that the re-calcination process decreased the loss on ignition from 20.9% to 2.1% at laboratory calcination thus increasing the silica content of the ash. Re-burnt SCBA provided the control of setting times and the evolution of the compressive strength of concrete changed with the nature of the used ash with a superior behavior being observed for lab-conditioned re-calcination SCBA.

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