Assessment of sugar cane straw ash (SCSA) as pozzolanic material in blended portland cement: Microstructural characterization of pastes and mechanical strength of mortars

The aim of this paper is to assess the pozzolanic reactivity of sugar cane straw ash (SCSA) obtained through an auto-combustion process and the mechanical properties of SCSA-containing systems. Characterization of SCSA (X-ray diffraction, chemical composition, particle size, and microscopy) and reactivity studies on hydrated lime/SCSA and Portland cement/SCSA pastes through infrared spectroscopy, thermogravimetric analysis, and microscopy demonstrated the high pozzolanic activity. This reactivity made it possible to achieve good mechanical properties in mortars in which 15 30% of the cement was replaced by SCSA. After 90 days of curing, the SCSA fixed 100% of the lime present in lime/SCSA pastes, and the compressive strength of mortars containing SCSA reached 44 MPa, a value similar to those found for control mortars after the same number of curing days. The results for the microstructural and mechanical properties showed that SCSA is a good pozzolanic material.The authors would like to thank CNPq-Brazil (process no 401724/2013-1) and the Ministerio de Educacion, Cultura y Deporte of Spain (the Cooperacion Interuniversitaria program with Brazil: PHB-2011-0016-PC). We also thank CAPES-Brazil for the Grant for J.C.B. Moraes and Electron Microscopy Service of the Universitat Politecnica de Valencia.Moraes, JCB.; Akasaki, JL.; Melges, JLP.; Monzó Balbuena, JM.; Borrachero Rosado, MV.; Soriano Martinez, L.; Paya Bernabeu, JJ.... (2015). Assessment of sugar cane straw ash (SCSA) as pozzolanic material in blended portland cement: Microstructural characterization of pastes and mechanical strength of mortars. Construction and Building Materials. 94:670-677. doi:10.1016/j.conbuildmat.2015.07.108S6706779