Experimental study on compressive mechanical properties of underwater non-dispersible polymer with AE.

Underwater non-dispersible polymer (UNDP) is utilized as a grouting material for repairing interlayer gaps in track structures located in water-rich environments. Understanding the compression properties of UNDP is crucial for assessing the longevity of track structures and ensuring the safe operation of trains. In this paper, uniaxial compression tests of UNDP specimens with different curing ages (0.125–28 days) were conducted. The deformation and cracks expansion of the specimens during the loading process were investigated by the acoustic emission (AE) technique and scanning electron microscope (SEM). Furthermore, the compression constitutive model of UNDP was established based on strain-stress curves. Test results indicate that the compressive strength of UNDP reached 22.63 MPa after three hours and stabilized at 30 MPa after 14 days. The stress-strain curves exhibited distinct staged characteristic, which can be divided into the compaction stage, the plastic deformation stage and the damage failure stage. The specimens with different curing ages showed the similar failure modes with a maximum axial deformation of 33%. The internal cracking pattern changed with the increase in curing ages, transitioning from dominant tensile cracks to shear cracks. At a curing age of 14 days, shear cracks were found to be 51.43%. In addition, SEM images revealed that the microstructure of UNDP consisted of a polyurea cross-linked backbone-water glass gel-filled structure. A constitutive model considering the curing ages was also proposed. This study provides a reference for water-rich environment application of this Underwater non-dispersible polymer. • Compression damage evolution and failure modes of UNDP were investigated. • Acoustic emission signal characteristics and microstructure of UNDP were analyzed. • Compression constitutive modes of UNDP considering the curing age was proposed. [ABSTRACT FROM AUTHOR]