Experimental Study on Crack Repair of Timber Components Using Nano-SiO 2 Reinforced Water-Based Epoxy Resin

Long-term practice shows that deterioration of timber structures mainly originates from intrinsic wood damage. Cracks in timber members reduce load-bearing capacity and promote further decay and moisture-related deterioration. This study simulated cracks using artificially grooved specimens and proposed a water-based epoxy resin — nano-SiO2 composite repair system. Macroscopic mechanical tests and microscopic analyses were conducted to assess failure characteristics, bending and compressive strength, stiffness, recovery rates, and interfacial enhancement. Results indicate that crack length predominantly affects bending performance, while crack depth mainly influences compressive behavior. The repair effectively filled cracks and enhanced overall performance, with nano-SiO2 improving interfacial bonding through physical filling and chemical cross-linking. At 1.5% nano-SiO2, the interfacial enhancement index (IEI) reached ≥1, indicating strong reinforcement; at 2%, local agglomeration reduced effectiveness (IEI < 1). These findings demonstrate that the water-based epoxy resin — nano-SiO2 composite can effectively repair cracked timber, offering guidance for the conservation of timber structures.