Compressive mechanical properties of self-expanding grouting materials with different densities.

• The evolution processes of the surface strain field and internal damage of the self-expanding grouting materials were analyzed. • Effect of density on the mechanical properties was evaluated. • A compressive stress–strain model before yielding considering the density variation was established. The compressive mechanical properties of self-expanding grouting materials with different densities are essential in evaluating the ultimate conditions of the repaired underground infrastructure. In this study, digital imaging correlation (DIC) and acoustic emission (AE) techniques were applied to monitor the compressive damage evolution process of self- expanding materials with different densities. It was found that the varied density exhibits great effect on the compressive response of self-expanding grouting materials, and that the length of the horizontal yield plateau decreases with the density. As the density increases to 0.399 g/cm3, the horizontal yield plateau diminishes and the materials present from plastic to brittle characteristics. Moreover, a statistical damage constitutive model of the ascending branch was developed and validated by experimental results. [ABSTRACT FROM AUTHOR]