An experimental study on the mechanical behaviour of two polyurethane resins used for geotechnical applications

The objective of this paper is to experimentally investigate the mechanical behaviour of different polyurethane expanding resins, which are widely used for ground improvement and foundation remediation. This study is the first step towards the primary objective, which is to define a design procedure for this type of intervention. This study encompasses two goals: (1) develop a relationship between the density of the resin and the confinement pressure in expansion conditions, and (2) measure the mechanical parameters from simple compression tests on resin specimens. Experimental tests were performed on two different types of resin, and the results reveal that the higher the confinement stress is during the expansion phase, the greater the hardened resin density. Moreover, the resin density and confinement stress are linked by a well-defined law. The laboratory tests show how the stress-strain behaviour is strongly non-linear and that both the elastic and strength parameters greatly depend on the boundary conditions during the expansion phase.