Kuat tarik belah beton yang rendah menjadi masalah penting yang dapat diatasi dengan penambahan serat dalam campuran beton. Serat ijuk dipilih karena ketersediaannya yang melimpah. Namun, penambahan serat ijuk dapat menurunkan workability beton, sehingga diperlukan bahan admixture seperti superplasticizer untuk memperbaikinya. Tujuan penelitian ini yaitu mengetahui nilai slump, nilai kuat tekan, dan nilai kuat tarik belah beton yang ditambahkan serat ijuk panjang 3 cm dan superplasticizer 2% dengan variasi penggunaan serat ijuk sejumlah 0%, 2,5%, 5%, 7,5%, 10%. Nilai slump beton masing-masing variasi secara berurut sebesar 8,758 cm, 9,092 cm, 8,800 cm, 8,592 cm, 7,967 cm dan 7,617 cm. Ketika berada di umur 28 hari, nilai kuat tekan beton masing-masing variasi secara berurut yakni senilai 25,370 MPa, 26,125 MPa, 25,842 MPa, 25,748 MPa, 25,559 MPa dan 25,465 MPa sedangkan untuk nilai kuat tarik belah masing-masing variasi secara berurut yakni senilai 2,028 MPa, 2,146 MPa, 2,264 MPa, 2,311 MPa, 2,358 MPa dan 2,452 MPa. Kuat tekan yang paling tinggi dicapai pada beton dengan tambahan 2% superplasticizer sedangkan kuat tarik belah yang paling tinggi berada pada beton dengan tambahan 2% superplasticizer dan 10% serat ijuk.

The low tensile strength of concrete is a serious problem that could be overcome by the addition of fiber to the concrete mix. Ijuk fiber was chosen because of its abundant availability. However, adding ijuk fiber can reduce the workability of concrete, so admixture such as superplasticizers are needed to improve it. This study was conducted to determine the slump value, also compressive and tensile strength of concrete using 3 cm of and 2% superplasticizer ijuk fibers as the addition materials, with variations in ijuk fiber content of 0%, 2,5%, 5%, 7,5%, and 10%. Slump values for each variation were 8,758 cm, 9,092 cm, 8,800 cm, 8,592 cm, 7,967 cm and 7,617 cm, respectively. At 28 days, the concrete’s compressive strength for each variation was 25,380 MPa, 26,125 MPa, 25,842 MPa, 25,748 MPa, 25,559 MPa, and 25,465 MPa, while the tensile strength for each variation was 2,028 MPa, 2,146 MPa, 2,264 MPa, 2,311 MPa, 2,358 MPa, and 2,452 MPa, respectively. The highest value for compressive strength was found in concrete with the addition of 2% superplasticizer while the highest tensile strength was achieved in concrete with the addition of 2% superplasticizer and 10% ijuk fiber.