Experimental investigation on the compressive mechanical properties of the non-aqueous reacting polymer with AE and DIC techniques

As a new type of non-excavation repair material, non-aqueous reacting polymer (NARP) is increasingly adopted in rehabilitation engineering. Properly evaluating the compressive mechanical properties of NARP with different densities is crucial for optimizing the repair design in engineering practices. However, due to a lack of experiments, the mechanism of the compressive mechanical properties of NARP influenced by the density is still not clear, and the constitutive model applicable for NARP with a wide range of density has also not been established yet. In this study, the compression characteristics of NARP with different densities under uniaxial compressive loading were comprehensively investigated, by using the acoustic emission (AE) and digital image correlation (DIC) techniques. Consequently, a statistical damage constitutive model considering the effect of density was established. The results showed that both the compressive yield strength and the elastic modulus of the NARP were strongly correlated with the density, and the correlated relationships can be characterized by two separate quadratic polynomial functions. The damage pattern of the NARP mainly changed from a ductile mode with low-density (ρ < 0.4 g/cm3) to a brittle mode with high-density (ρ > 0.4 g/cm3). The high-density NARP tends to exhibit a significant compressive brittleness. The AE signals were detected throughout the uniaxial compression experiments and the released AE activity was stronger at the same strain with a higher polymer density. Both the pre- and post- yield stages of NARP materials with different densities can be well characterized by using the proposed statistical damage model, being capable of considering the effect of density. The findings on the deformation and damage mechanism, together with the established constitutive model, have significant implications for the design of NARP in engineering practices.