Work

Mechanical Behavior of Polyurethane-Reinforced Coral Sand Under Unconfined Compression

Year: 2026

Type: article

Abstract: The low bearing capacity and high crushability of coral sand pose major challenges to island and reef foundation engineering. Herein, a newly developed non-isocyanate polyurethane was used to reinforce coral sand and the unconfined compressive behavior of polyurethane-reinforced coral sand was investigated based on an orthogonal experimental design. The effects of particle gradation, the mass ratio of polyurethane to sand and moisture content on strength, deformation, and energy evolution were analyzed. The results show that the highest uniaxial strength of 5.48 MPa was obtained for naturally graded coral sand with a polyurethane mass ratio of 30% under dry conditions. The moisture content was identified as the dominant factor affecting the strength, and elastic modulus of the reinforced samples. Increasing moisture content significantly reduced the crack initiation stress, dilation strength, peak strength and elastic modulus, while increasing Poisson's ratio. In contrast, a higher polyurethane mass ratio improved the strength, stiffness and energy dissipation capacity, whereas particle gradation primarily influenced the crack initiation stress level. Under unconfined compression, the reinforced samples mainly exhibited ductile shear failure involving edge breakage, particle sliding, delamination and rupture of the cured polyurethane film. Microscopic observation indicated that the cured polyurethane worked as a surface film, an interparticle bridge and a pore-filling phase within the coral sand matrix. The enhancement in mechanical behavior was mainly associated with polymer bridging, pore filling, local interfacial adhesion and mechanical interlocking.

Source: Polymers

DOI: 10.3390/polym18141744

Authors: Linjian Ma, Hui Li, Fa Yang, Yanyan Cai, Hansheng Geng, Jian’an Wu

Institutions: PLA Army Engineering University, Chinese People's Liberation Army, Huaqiao University

Language: English

Topic: Geotechnical Engineering and Soil Stabilization

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $3,258