Sugar cane bagasse ash, a byproduct of sugar and alcohol production, is a potential pozzolanic material.
However, its effective application in mortar and concrete requires first the controlled use of grinding and
classification processes to allow it to achieve the fineness and homogeneity that are required to meet
industry standards. The present paper investigates the role of mill type and grinding circuit configuration in
grinding in laboratory- and pilot plant-scale on the particle size, specific surface area and pozzolanic activity
of the produced ashes. It was observed that, although different size distributions were produced by the
different mills and milling configurations, the pozzolanic activity of the ground ash was directly correlated to
its fineness, characterized by its 80% passing size or Blaine specific surface area. From a low pozzolanic
activity of less than 50% of the as-received ash, values above 100% could be reached after prolonged grinding
times. Electric power requirements to reach the minimum pozzolanic activity were estimated to be in the
order of 42 kWh/t in an industrial ball mill. Incorporation of an ultrafinely-ground ash in a high-performance
concrete in partial replacement of Portland cement (10, 15 and 20% by mass) resulted in no measurable
change in mechanical behavior, but improved rheology and resistance to penetration of chloride ions.