Mechanical behavior of polymer stabilized sand under different temperatures

Abstract

In this study, the mechanical behavior of a polyurethane (PU) polymer-sand mixture was investigated by performing a series of uniaxial compression (UC) and direct tensile (DT) tests at different polyurethane polymer contents (PUC), dry densities (DD) and temperatures (TP). Results show that the axial stress–strain relationship depends on PUC, DD and TP, in particular, the failure mode gradually changes from fragile to ductile feature; the uniaxial compressive strength (UCS), secant modulus (E50) and tensile strength (TS) all linearly increase with increasing PUC and DD at different TPs. Positive and negative temperatures (i.e., 35℃ and 50℃, −20℃ and − 10℃) both make positive effect on PU treatment since the UCS ratio, E50 ratio and TS ratio all are higher than unity. Positive temperature significantly increases the strength and ductility, while negative temperature obviously affects the strength and modulus. Linear relationships of E50-UCS, UCS-TS are obtained, and these relationships depend on temperature. Scanning electron microscope (SEM) observation reveals that the presence of PU additive links adjacent grains together, improving the mechanical properties of the mixture. As this bonding effect is expected to be dependent on PUC, DD and TP, the strength, ductility and stiffness are different in different scenarios.