Title: Pozzolanic Reaction of a Biomass Waste as Mineral Addition to Cement Based Materials: Studies by Nuclear Magnetic Resonance (NMR)
Author(s): Sagrario Martínez‑Ramírez , Moisés Frías, Erika Y. Nakanishi and Holmer Savastano Jr.
Appears on pages(s):
Keywords: biomass ash, pozzolan, nuclear magnetic resonance spectroscopy, C-S-H gel, microstructure
Non-fossil alternative fuels from biomass (agro-industrial, forestry and fodder plants) focus on getting cleaner, cheaper
and more environmentally friendly energy sources directly related to the sustainable development of future societies.
The resulting ash produced from the biomass calcination is a viable alternative for use as supplementary cementing
materials in the construction industry. This study explores the scientific knowledge of calcium-silicate hydrate (C-S-H)
gel formation during pozzolanic reaction between the biomass ash and calcium hydroxide through nuclear magnetic
resonance technique with two different types of elephant grass ash that have different microstructure. The ash with
the highest initial percentage of Q4
units was found to react most actively and give rise to gels with the greatest
inter-tetrahedral connectivity. In contrast, ash with higher content of total SiO2, exhibited lower reactivity and the
C-S-H gel formed is characterised by low inter-tetrahedral connectivity from the earliest ages. Evaluation of C-S-H gel
by nuclear magnetic resonance (NMR), as main hydrated phase for the engineering properties, revealed the potential
of this tool to determine the effectiveness of this type of grass as raw material in cementing matrices through the
evolution of the microstructure of the gel C-S-H formed.