Abstract: Sea sand coral concrete(SSCC) has poor crack resistance and obvious brittleness, which has greatly drawbacked its application. In order to improve the brittleness and enhance the cracking resistance of SSCC, polypropylene fiber (PF) was added into the concrete to prepare a new type of marine concrete, that is, polypropylene fiber sea sand coral concrete (PFSSCC). Macroscopically, the mechanical properties and constitutive relationship of PFSSCC were investigated by basic mechanical property tests and prismatic uniaxial compression tests. Microscopically, the scanning electron microscope (SEM) was used to observe the microstructure of PFSSCC and analyze the PF-enhancement mechanism. The results show that the typical damage pattern of uniaxial compression of PFSSCC is shear damage and the integrity after damage is good. When the PF doping is 0.2%, PFSSCC shows better performance, compared with the benchmark group, the splitting tensile strength, peak strain, compressive toughness index and ductility coefficient increased by 16.0%, 8.7%, 57.7%, and 40.8%, respectively. The slope of the descending section of the stress-strain curve of the sea sand coral concrete after fiber toughening is slowed down, and the brittleness is effectively improved. The uniaxial compression constitutive model established based on the experimental data considering the compressive strength of the concrete and the polypropylene fiber dosage can effectively predict the stress-strain behaviour of the PFSSCC under uniaxial compression. These provide a test case and a theoretical basis for the practical application of the PFSSCC in the offshore engineering. In addition, the failure modes of PF were observed to be pull-out and breakage by SEM.
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