Effects of adding sugarcane bagasse ash on the properties and durability of concrete

Ashes from biomass burning, such as from sugarcane bagasse, have great potential as supplementary cementitious materials. The sugarcane bagasse ash (SCBA) possesses high pozzolanicity. However, limited studies have investigated the influence of SCBA on the durability of concrete. A knowledge gap exists regarding the influence of these ashes on the lifetime of reinforced concrete in terms of chloride migration and carbonation. Moreover, additional studies on the effects of SCBA on the alkali-silica reaction (ASR) are essential because this ash generally has a high alkali content. In this study, the effects of adding 5%, 10%, and 15% SCBA on the properties and durability (chloride migration, carbonation, and alkali-aggregate reaction) of concrete were investigated. Furthermore, the SCBA pozzolanicity was evaluated and lifetime estimations in terms of chloride ingress and carbonation were performed. The studied ash demonstrated high pozzolanic activity, which reduced the porosity and water absorption by capillarity and increased the mechanical strength of the concrete. However, because the alkaline reserve was reduced, the concrete with SCBA exhibited a higher carbonation rate (up to 69%) and a shorter lifetime regarding carbonation. Nevertheless, all concrete specimens had a lifetime of more than 50 years in an industrial environment, except for that with 15% SCBA. Adding SCBA also reduced the chloride diffusion coefficients, increasing the lifetime by up to 97.3%. SCBA addition of up to 5% mitigated the ASR owing to the pozzolanic reaction and additional C-S-H formation. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The study showed that adding 5%, 10%, and 15% sugarcane bagasse ash (SCBA) to concrete can reduce the porosity and water absorption, increase mechanical strength, but also lead to higher carbonation rate and shorter carbonation lifetime. In an industrial environment, all concrete specimens had a lifetime of over 50 years, except for that with 15% SCBA. Additionally, SCBA addition can lower chloride diffusion coefficients, increasing concrete lifetime by up to 97.3%.