Sugar cane bagasse ash from a high efficiency co-generation boiler: applications in cement and mortar production

Sugarcane bagasse ash (SCBA) has been reported to be beneficial as cement replacement due to the pozzolanic and the filler effect. The SCBA from a high-efficiency (high temperature) co-generation boiler does not contain significant amorphous silica rather it contains a-quartz generated by phase transitions during combustion. The high combustion temperatures appear to deactivate the silica, and lime-SCBA pastes show little or no pozzolanic activity present, except at a 5% replacement. Compressive strength testing of the cement pastes also suggests that at 5% cement replacement level, the SCBA is potentially pozzolanic. However, up to 15% SCBA cement replacements achieve a pozzolanic index above 75%, which suggests increases in pozzolanic activity by the relative strength tests are more likely from a filler effect than true pozzolanic activity. Despite an apparent lack of pozzolanic activity all SCBA’s additions improved sulphuric acid resistance measured both through compressive strength testing and mass loss measurements.