Three-dimensional fiber-reinforced composite and method for producing three-dimensional fiber-reinforced composite

A method for manufacturing a three-dimensional fiber-reinforced composite, the method comprising:

• preparing a laminate including fiber bundle layers that are layered in a lamination direction, wherein the fiber bundle layers include first and second outermost layers;
• preparing a retention yarn extending along a surface of the first outermost layer;
• binding the fiber bundle layers in the lamination direction with a binding yarn, wherein
• the binding yarn includes
• a fold-back section that is folded back on an outer side of the retention yarn in the lamination direction,
• a primary traverse yarn section and a secondary traverse yarn section that are continuous with the fold-back section and extended in a direction perpendicular to planes of the fiber bundle layers,
• surface yarn sections extending on a surface of the second outermost layer in directions perpendicular to the retention yarn along a plane of the second outermost layer, and
• the surface yarn sections include a bifurcated section that extends in opposite directions from the primary traverse yarn section and the secondary traverse yarn section on the surface of the second outermost layer;
• supplying an additive only to the bifurcated section from outside of the surface of the second outermost layer while drawing the additive from outside of the surface of the first outermost layer, thereby placing the additive only in a first cavity surrounded by the bifurcated section and fiber bundles of the second outermost layer that are adjacent to the bifurcated section, a second cavity between each of the primary traverse yarn section and the secondary traverse yarn section and fiber bundles that are adjacent to the traverse yarn sections, and a third cavity between the primary traverse yarn section and the secondary traverse yarn section;
• and
• impregnating the laminate that includes the additive with matrix resin.