Low-Carbon Bio-Concretes with Wood, Bamboo, and Rice Husk Aggregates: Life Cycle Assessment for Sustainable Wall Systems

Abstract

This study evaluates the carbon footprint of three bio-concrete families—wood (WBC), bamboo (BBC), and rice husk (RHBC)—and their application in wall components (as blocks and as boards). A cradle-to-grave, carbon-focused Life Cycle Assessment (LCA) was used to compare these bio-concretes to conventional masonry and industrialized light-framing solutions. Each bio-concrete family incorporated biomass volumetric fractions of 40%, 45%, and 50%, using a ternary cementitious matrix of cement, rice husk ash, and fly ash (0.45:0.25:0.30). Sensitivity analyses examined the impacts of transport distances and the parameters affecting biogenic carbon storage, such as carbon retention periods in the built environment. The carbon footprint results demonstrated a significantly low or negative balance of emissions: WBC ranged from −109 to 31 kgCO2-eq./m3, BBC from −113 to 28 kgCO2-eq./m3, and RHBC from 57 to 165 kgCO2-eq./m3. The findings emphasized the importance of ensuring bio-concrete durability to maximize biogenic carbon storage and highlighted the environmental advantages of bio-concrete wall systems compared to conventional solutions. For instance, BBC boards replacing fiber cement boards in light-framing systems achieved a 62 kgCO2-eq./m2 reduction, primarily due to the production (A1–A3) and replacement (B4) stages. This research outlines the emission profiles of innovative materials with the potential to mitigate global warming through circular construction, offering a sustainable portfolio for designers, builders, and AECO professionals seeking non-conventional solutions aligned with circular economy principles.