Experimental Study On The Anti-abrasion Performance Of Coral Reef Sand Concrete

Coral reef sand is a special type of rock and soil,which refers to the rock body formed by the bone remnants of reef-building coral groups after death.There are abundant natural resources such as coral reefs,sands,and seawater on coral islands and reefs in China.In order to reduce the cost of coral island reef construction,shorten the construction period,and save land and sand resources,especially in coral reef countries,there are no other building materials to choose from,so the construction of coral islands and reefs that are far from the land can be taken locally.The use of coral reefs and sand as concrete aggregates for the construction of coral islands and reefs has important practical significance.Under the harsh marine environment,the durability of coral reef sand concrete determines the long-term safety and stability of the islands,its research has great scientific significance and practical value.Based on the field investigation of damage modes of coral concrete structures in complex marine environments,this paper proposes damage modes of coral concrete in high temperature,high salt,high humidity,and high radiation marine environments.Among the harsh marine environments,the outside of the breakwater often suffers.The tidal waves are repeatedly washed and scoured by coral reef fragments,causing abrasion and damage to the surface of the breakwater and internal erosion damage,threatening the durability and stability of the reef revetment.Based on this,this paper comprehensively uses indoor macromechanical tests,microstructural tests and theoretical analysis to study the damage mechanism of erosion and abrasion of coral reef sand concrete and proposes measures to enhance the anti-abrasion performance of coral reef sand concrete to achieve effective improvement of the durability of breakwaters.The main research contents of this article are as follows:(1)Based on the field investigation on the damage of the coral reef sand concrete structures on the islands and reefs,the damage modes of the coral reef sand concrete are proposed to be three types: salt spray erosion,large-area expansion and erosion erosion,and the three types of damage mode mechanisms are given.(2)Aiming at the erosion and abrasion damage patterns of breakwaters and the field environment,coral reef sand concrete was prepared using slurry-rich theory and high-strength concrete technology,and studied fly ash(FA),silicon powder(SF),polypropylene fiber(PF),and basalt fiber(BF)and other admixtures and the age of curing affect the strength mechanical properties(cubic compressive strength and split tensile strength)and erosion resistance of coral reef sand concrete.As a result,it was found that fly ash(FA),silicon powder(SF),polypropylene fiber(PF),basalt fiber(BF),and curing age have different influences on the mechanical properties of coral reef sand concrete(cubic compressive strength and split tensile strength)and impact resistance.Studies have shown that the incorporation of silica fume can enhance the strength of coral reef sand concrete throughout its age.The incorporation of fly ash is not conducive to the early strength of coral reef sand concrete,but it can slightly increase its later strength and impact resistance to erosion.On the one hand,the addition of silica fume improves the anti-abrasion effect of coral reef sand concrete significantly better than fly ash.In addition,the incorporation of fibers is conducive to improving the split tensile strength and impact strength of concrete.Coral reef sand concrete has a linear relationship between the erosion resistance and compressive strength,which provides theoretical basis for improving the erosion resistance and long-term operation and maintenance of port structures such as breakwaters.(3)Coral reef sand concrete of different ages and ages mixed with fly ash(FA),silica fume(SF),polypropylene fiber(PF),and basalt fiber(BF)was tested with a microhardness tester at the interface area.The hardness value,the results show that different admixtures have different effects on the microhardness value of the interface area of coral reef sand concrete.The addition of silicon powder significantly increased the hardness of the weak area of the coral reef sand concrete interface,while theaddition of fly ash slightly reduced the hardness of the weak area of the coral reef sand concrete interface,and the addition of too much fiber was not conducive to improving the coral reef sand concrete interface.The hardness of the transition zone.There is a positive correlation between the average hardness of the interface area of the coral reef sand concrete and the splitting tensile strength,and there is a gap between the hardness of the interface area and the hardness of the coral reef sand.The difference can be explained,so the anti-abrasion performance of coral reef sand concrete can be judged based on the splitting tensile strength.