Nanocellulose in Cementitious Composites: Rheology, Buildability, Interlayer Bonding, and Mechanical Performance — A Systematic Literature Review

Abstract

Nanocellulose, comprising cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial nanocellulose, is gaining attention as a bio-based additive for modifying the fresh- and hardened-state behaviour of cementitious composites, yet the evidence remains scattered across cement paste, mortar, geopolymer, ultra-high-performance concrete (UHPC), and 3D-printed systems. This systematic review synthesises available evidence on nanocellulose-modified cementitious composites, focusing on rheology, buildability, interlayer bonding, and mechanical performance. Following the PRISMA 2020 guideline, a search of the ScienceDirect database identified 127 records, of which 37 met the eligibility criteria: primary, English-language, peer-reviewed articles reporting nanocellulose incorporation into a cementitious or geopolymer binder with at least one of the four target outcomes measured. Data on nanocellulose type and dosage, binder system, and reported outcomes were extracted and synthesised narratively. Low-dosage CNC and CNF additions (typically below 0.5 wt% of binder) were consistently associated with increased yield stress and viscosity, delayed or modified hydration, and higher early-age compressive and flexural strength, attributable to internal curing, nucleation, and nanoscale reinforcement; excessive dosages tended to cause agglomeration and porosity increases that offset these gains. Studies addressing buildability and interlayer bonding directly, mostly concerning 3D-printed systems, were comparatively few. The certainty of evidence is limited by heterogeneity in nanocellulose source, dosage, and testing protocol, by reliance on laboratory-scale specimens, and by the restriction of the search to a single database. Nanocellulose is a viable rheology-modifying and strength-enhancing additive for cementitious systems, and dosage optimisation and standardised testing protocols remain priorities for future research. The evidence base is markedly uneven across outcomes (mechanical performance, 35 of 37 studies; rheology, 12; buildability, 6; interlayer bonding, 2), and screening and appraisal relied on titles, abstracts and metadata rather than full-text articles, which the Discussion identifies as the principal limitations on the certainty of these conclusions.