Abstract：Using natural coral debris as coarse aggregate,under the condition of water cement ratio of 0.4,it was studied the basic mechanical indexes of different content of carbon fiber,polypropylene fiber and sisal fiber coral aggregate concrete.Results showed that the cube compressive strength,splitting tensile strength,bending strength,and elastic modulus of coral concrete firstly increased and then decreased with fiber content increase.Overall,the optimal content of carbon fiber was 2 kg / m3,and that of polypropylene fiber was 2 kg /m3,and that of sisal fiber was 4.5 kg / m3.When mixed with fiber excess,the dispersibility in coral aggregate concrete is reduced,and slurry weak interface increased.So it cannot play its enhancement and toughening effect that the intensity decreased.In addition,mixing fiber into coral aggregate concrete can obviously improve the brittleness,toughness and bending performance significantly,and change the damage form of coral aggregate concrete,therefore,whem the specimen destroyed,it can still maintain good integrity.

Keyword：coral aggregate concrete;fiber reinforced;flexural strength;damage morphology;