Statistical Characteristics of Polymer Grouting Material Microstructure

Abstract

The two-component foaming polyurethane is a kind of grouting material that has recently been widely used in engineering structural repair. Its physical and mechanical properties are closely related to its microstructure. Therefore, the qualitative and quantitative analysis of polymer microstructure has always been a research hotspot. The statistical characteristics of polymer grouting material microstructure are investigated by six groups of specimens with different densities, and the density varies from 0.1 to 0.6 g/cm3. The microstructure morphology of polymer was observed and described by scanning electron microscopy (SEM), and the microstructure feature parameters were extracted and calculated by image processing technology. The quantitative analysis of section cell roundness distribution, cell diameter distribution, and polymer porosity shows that low-density polymer materials have anisotropy. While the density exceeds 0.3 g/cm3, the cell structure tends to be spherical. The section cell diameters obey a normal distribution, and when the density increases, the cell diameter decreases. The porosity of the polymer has a linear negative correlation with the density. The polymer matrix has a density of 1.21 g/cm3. The microstructural information obtained in this study will help establish a cell-based model to explain the mechanical response of rigid polymer foams.

Construction of Dielectric Model of Nonaqueous Reactive Polyurethane Grouting Materials

“…In view of the porous characteristics of nonaqueous polyurethane materials on the microscopic scale, electron microscopy experiments are required to observe the microstructure of nonaqueous polyurethane specimens. Due to the limited test environment, the electron microscope photo of the reference [31] in this paper deduces the physical model and draws four conclusions.…”

Polyurethane grouting materials with different compositions for the treatment of mud pumping in ballastless track subgrade beds: properties and application effect

“…Polyurethane grouting is widely applied in highways, housing construction, and underground engineering. Polyurethane grouting materials have been investigated experimentally and/or theoretically from many aspects, including material synthesis and modification [21][22][23], mechanical and macroscopic properties [24][25][26][27][28], the evolution mechanism of macro-mechanical properties and microstructure characteristics [29][30][31][32], and the diffusion mechanism and expansion characteristics of polymer grout [33][34][35][36][37]. However, existing studies have mainly focused on the engineering backgrounds of water conservation, structure lifting, and foundation treatment and reinforcement.…”