Supersulphated cement from cane bagasse ash, lime and calcium sulfate for non structural applications, Nicaragua

Abstract

Portland cement is the most used binder worldwide, however, its production involves the emission of 1 kg of CO₂ for every 1 kg of cement produced. The development of sustainable cements is necessary, with good mechanical performance, but friendly to the environment. A supersulfated cement based on sugarcane bagasse ash (SCBA) activated with calcium oxide  (CaO) and calcium sulfate (CaSO₄) was elaborated, obtaining a maximum value of mechanical strength (MS) of 10.75 MPa, for the mixture with a composition of 80% SCBA, 10% CaO and 10% CS. The experimental Taguchi setup was an L₁₈ (6¹ x 3²). 18 tests were carried out in triplicate, varying the mass ratios of the three main reagents. An ICT was used with three levels: room temperature (~35 ºC), 50 ºC and 100 ºC and a water/binder ratio with levels of 0.25, 0.30 and 0.35. A chemical characterization was carried out using Fourier transform infrared spectroscopy (FT-IR), to know the possible reaction products, being able to identify products such as lime, ettringite, silica gel and potentially CSH. Finally, the effect of the alkaline activator was determined, carrying out control tests without CaO and without CS, obtaining an MS of 7.72 MPa to the control without CS and 1.38 MPa for the control without CaO, highlighting the importance of CaO in the formation of CSH-gel.