Study on mechanical properties and anti-erosion performance of fiber reinforced seawater sea sand concrete

Abstract

Listen

Translate article

In order to study the mechanical properties of seawater sea sand concrete and the durability damage law of seawater sea sand concrete under the action of seawater erosion, corresponding specimens were prepared and subjected to cube compressive strength, flexural strength, and dry-wet cycle tests by taking the volume dosage of glass fibers and polyvinyl alcohol fibers as variables. The test combined SEM scanning and EDS to analyze the microstructure of fiber-reinforced seawater sand concrete, and established a model based on the two-parameter Weibull probability distribution. The results show that the fiber has a significant effect on improving the mechanical properties and erosion resistance of seawater sand concrete. When the total volume content is 0.3% and the mixing ratio is 1:1, the improvement effect is the best. The maximum increase in cubic compressive strength was 24.2%; the maximum increase in flexural strength was 38.8%. After the specimens were subjected to wet and dry cycles for 360d, the maximum reduction in mass loss rate was 41.23%; the maximum reduction in strength loss rate was 27.55%. As observed from the microscopic images, the main disadvantage of SSC is that the salt crystallization and swelling matter produced by the erosion ions will weaken the bond between aggregate and mortar, resulting in defects in the interfacial transition zone (ITZ). Under the action of dry-wet cycles, the alternating dry-wet forces, the expansion pressure generated by expansive substances and the crystallization pressure generated by salt crystallization will change the microstructure, and therefore the damage of the specimen will deepen with the extension of erosion time. The microscopic images also show that the doping fibers can improve the internal integrity and compactness of the matrix, thus significantly improving the mechanical properties and durability of seawater sea sand concrete. In this test, a damage model was established based on the two-parameter Weibull distribution model, and the damage law between strength loss and dry-wet cycles was fitted, which provides a favorable basis to study the damage of seawater sea sand concrete under wet-dry cycling.