A review of the use of sugarcane bagasse ash with a high LOI content to produce sustainable cement composites

Abstract

In recent years, agricultural wastes have been employed as supplementary cementitious materials to produce sustainable cement composites. One of these wastes is the sugarcane bagasse ash (SCBA). The SCBA is available in large quantities in developing countries such as Brazil, India and Mexico, and its disposal is causing different environmental issues. The SCBA has high amounts of silicon, aluminum and iron oxides as major components. Several researchers report that the high amount of these oxides leads to the improvement of the mechanical and microstructural properties of cementing composites containing the SCBA. On the other hand, a high amount of unburned carbon, commonly expressed by the loss on ignition (LOI), could be also present in the SCBA due the inefficient burning process of the bagasse in the boiler in sugar mills. It has been reported that this high LOI content in the SCBA change the water requirement and the rheological properties of cement binders. This might adversely affect the mechanical, microstructural and durability properties of hardened cement composites prepared with this material as well. In order to decrease the LOI content of the SCBA the combination of sieving, grinding and recalcination have been proposed; however, these methods are highly demanding in energy and generate additional contaminants. Sieving is the less energy demanding procedure and appears to be an interesting approach to post-treat the existing SCBA in open damps. Based on the above, this paper presents a review on the effects of the use of SCBA with a high LOI content to manufacture cement composites