Assessing the pozzolanic activity of sugarcane bagasse ash using X-ray diffraction

•Calcination and grinding clearly increased SBA pozzolanicity.•Methods to measure calcium hydroxide consumption by XRD analysis were studied.•Relative decrease in calcium hydroxide peak intensity (CH RDPI) provided relevant information about SBA pozzolanicity.•CH RDPI presented a strong correlation with data from other pozzolanic activity tests. This paper proposed to assay the pozzolanic activity of different types of sugarcane bagasse ash (SBA) using the X-ray powder diffraction technique. The as-received SBA presented a high loss on ignition and a coarse particle size, and then, the processing employed calcination and grinding. Pastes and mortars formed with SBA and calcium hydroxide were used for X-ray powder diffraction, thermogravimetric analysis, and compressive tests. The evaluation of the pozzolanic activity was based on the measurement of the calcium hydroxide amount by a relative decrease in peak intensity (RDPI) at 18° and 34° (2θ), RIR, and Rietveld refinement analysis. These results were compared with the data obtained from thermogravimetric analysis and compression tests, and showed good correlation. In the correlation matrix, all p-values were below 0.05, indicating that the variables did not show any independence from each other. Finally, it was concluded that assessing CH consumption only by the RDPI, even considering a low-accuracy method, can be a relevant tool for evaluating the SBA pozzolanic activity.