Influence of self-curing agents and sustainable additives on repair mortar: a two-way ANOVA approach

This study explores Engineered Cementitious Composites (ECC) as a sustainable repair mortar, enhanced through polymer incorporation and internal curing. Styrene-butadiene rubber (SBR) latex was introduced at 2–6%, and polyethylene glycol (PEG) at 0.5–1.5%, supported by prior studies and preliminary trials. Supplementary cementitious materials (silica fume, fly ash, ground granulated blast-furnace slag) were incorporated to improve matrix densification and durability. The mixes were evaluated for fresh (flow, setting, viscosity), mechanical (compressive, flexural, tensile), bond, and durability properties (sorptivity, shrinkage, chloride penetration, acid resistance, ultrasonic pulse velocity), with statistical analysis via two-way ANOVA. Results revealed that 4% SBR significantly enhanced flexural and bond strength, though compressive strength was reduced due to entrapped air. PEG at 1% improved hydration and shrinkage resistance, while higher dosages impaired strength. SCM-modified mixes provided notable resistance against chloride ingress. ANOVA confirmed significant main and interaction effects, highlighting trade-offs between strength, durability, and crack control. Compared with commercial mortars, modified ECCs showed superior bond, durability, and crack resistance despite compressive strength reductions. Study limitations include the absence of long-term durability evaluation, micromechanical modelling, and detailed fracture surface analysis. Overall, PEG- and SCM-modified ECCs present a cost-effective and durable self-curing repair solution, requiring further optimisation and long-term validation.