Dual Nanoparticles Synergistically Reinforce Polyurethane/Epoxy Grouting Material with High Mechanical Properties and Low Volume Shrinkage
Xiaodan Li, Dan Tian, Feng Wang, Xiaolong Shen, Xiongrui Cai, Shiyun Meng, Lei WangABSTRACT
To overcome the performance limitations of single‐resin grouting materials in complex construction environments, this study introduces nano‐SiO 2 and nano‐Al 2 O 3 as synergistic reinforcements into a polyurethane/epoxy (PU/EP) blend emulsion to develop a high‐performance composite grouting material. The nanoparticles were incorporated at controlled loadings to mitigate agglomeration, which elevated slurry viscosity and shortened the initial setting time, while preserving the intrinsic porous structure of the matrix. Nano‐SiO 2 primarily enhanced toughness, improving impact and tensile strength, whereas nano‐Al 2 O 3 contributed to strength and rigidity, enhancing compressive and wet adhesive properties. The synergistic combination of both nanoparticles resulted in a balanced and superior overall performance: compared to 1Si/PU/EP, 1.5Si/Al/PU/EP exhibited increases of 22%, 48%, and 29% in tensile, compressive, and adhesive strengths, respectively; compared to 1.5Al/PU/EP, these properties of 1.5Si/Al/PU/EP improved by 193%, 12%, and 27%, along with a remarkable 207% enhancement in impact strength. The composite also achieved a low volume shrinkage rate of 0.39%. Grouting model tests confirmed excellent injectability and reinforcement performance, with the consolidated body reaching a compressive strength of 68 MPa.