In a significant stride towards sustainable construction, researchers have developed a novel method to enhance the use of biomass fly ash (BFA) in cementitious materials. This innovation, spearheaded by Yaru Yang from the Graduate School of Environmental Engineering at the University of Kitakyushu in Japan, could have substantial implications for the maritime industry, particularly in shipbuilding and offshore construction.
Biomass fly ash, a byproduct of bioenergy generation, has long been recognized for its potential sustainability benefits. However, its irregular morphology and high residual carbon content have limited its reactivity and applicability in cementitious systems. To overcome these challenges, Yang and her team proposed an integrated flotation-ball milling pretreatment. This process not only removes unburned carbon but also activates BFA, significantly enhancing its physicochemical reactivity.
The study, published in the journal “Case Studies in Construction Materials” (translated from English), demonstrated that flotation effectively removed unburned carbon, while moderate ball milling refined the particle structure and increased amorphous content. “Moderate ball milling for 30 minutes improved flowability by approximately 10% compared with untreated BFA,” Yang explained. This pretreatment led to a 28% higher 28-day compressive strength in mortars incorporating modified BFA compared to those with untreated BFA.
For the maritime industry, these findings present a promising opportunity to reduce carbon emissions and promote waste utilization. The use of modified BFA in cementitious materials could enable an estimated 30% reduction in CO₂ emissions relative to pure cement. This is particularly relevant for shipbuilding and offshore construction, where large quantities of cementitious materials are used.
However, the study also cautioned against excessive milling. “Excessive milling for 90 minutes induced particle agglomeration and diminished performance gains,” Yang noted. This highlights the need for careful optimization of the pretreatment process to achieve the best results.
The research also revealed that modified BFA samples exhibited a higher proportion of fine pores and fewer macropores, consistent with lower calcium hydroxide (CH) contents and higher amorphous phase fractions. This indicates enhanced pozzolanic reactivity, which is crucial for the long-term durability of cementitious materials.
In summary, the flotation-milling pretreatment developed by Yang and her team effectively improves the reactivity of biomass fly ash as a low-carbon supplementary cementitious material. This innovation not only promotes waste utilization but also contributes to carbon reduction in sustainable construction, offering significant opportunities for the maritime industry to adopt more eco-friendly practices.