Portland cement, gypsum and fly ash binder systems characterization for lignocellulosic fiber-cement

•pH and electrical conductivity assessment of Portland cement, gypsum and fly ash binders.•TG and DTA analysis of ternary blended systems and their components.•SEM for lignocellulosic fiber durability evaluation under low-alkaline environments.•Fibers preservation within low-alkaline matrices by specific energy conservation in flexural tests.

The present work aims to obtain an optimal Portland cement, gypsum and fly ash (OPC-G-FA) ternary binder matrix and assess both the addition of paper pulp-by means of mechanical dispersion in aqueous suspension-for cementitious composites reinforcement and the fiber properties over time. To evaluate microfibers preservation from pulp in low-alkaline environments, ternary binder matrices OPC-G-FA are optimized to achieve lower pH values. For that purpose, pH and electrical conductivity over time were analyzed. Only samples with the lowest content in Portland cement (15–20%) offered low alkalinity for short-term. The use of ternary binder systems enhances microfibers conservation compared with control samples (matrices 100% Ordinary Portland Cement) by using FA that, as expected, reduces the presence of Ca(OH)2 in the matrix. Mechanical results prove that obtained matrices yield to a mechanical properties maintenance unlike samples with OPC matrices where toughness is reduced by 95%.