Tests on the Indonesian coconut fiber showed that, compared to the results of previous studies, tensile strength and tension failure improved after the fiber was washed with water and dried. This study aims to obtain the effects of fiber length and fiber content on splitting tensile strength behavior of the concrete composite reinforced with coconut fiber. Experimental observations were carried out on the splitting tensile strength of coconut fibers as determined by the fiber content (1, 2, 3, and 4 % by a mass ratio of fiber per cement) and the length of the fibers (5, 20, 40 mm) in the concrete. The results show that a coconut fiber length of 5 mm and a fiber content of 3 % in fiber concrete composite gives the composite 1.28 times higher splitting tensile strength than plain concrete. The density of the fiber concrete composite decreases with the addition of coconut fiber content.

The development of nanotechnology continues to grow. The use of nanocement in concrete is expected to reduce the number of pores and improve hydration in concrete and provide more strength to the concrete. The use of natural fibers, in this case, coconut fiber can prevent cracks in concrete and make fiber concrete more ductile than ordinary concrete. The effect of using nanocement on coconut fiber concrete on the strength of the concrete to be studied. Methodology to complete the research objectives, use nanocement used in concrete, which has added coconut fiber. Tests reviewed the value of slump and specific gravity. Then, testing the compressive strength at 7, 24, 28 days. The results obtained were an increase of 48.19% in the strength of concrete. Further research needs to review on mixing nanocement with other natural fibers.