Proceedings of International Structural Engineering and Construction, 8(1), 2021 Interdisciplinary Civil and Construction Engineering Projects Edited by El Baradei, S., Abodonya, A., Singh, A., and Yazdani, S. Copyright © 2021 ISEC Press ISSN: 2644-108X www.doi.org/10.14455/ISEC.2021.8(1).MAT-13 MAT-13-1 EFFECTS OF REPLACING CEMENT BY DATE PALM TREES WASTES ON CONCRETE PERFORMANCE AHMAD S. E. NASSEF 1, 2 , KALIFA H. AL-MAQBALI 1 , and SHEIKHA M. AL NAQABI 1 1 College of Engineering, University of Buraimi, Buraimi, Oman 2 Faculty of Engineering – Matria – University of Helwan, Cairo, Egypt This paper was studying the effects of palm tree wastes on the behavior of the concrete to reduce cement content in the concrete to ensure a sustainable environment. Both fibers of palm tree and the ash of palm tree leaves are used in this study considering different percentages of palm tree wastes, which are replaced the cement, to investigate both of workability and strength of the concrete. Also, the combination of palm tree leaves ash and fibers of palm trees is investigated. The slump and compression tests are carried out to evaluate both workability and concrete strength. The palm fibers were reducing the workability of concrete at both of different percentage of replacement and different fiber lengths. The slump is reduced by 26.667% at 2 cm fibers length and it is completely lost at 5 cm length fibers at the same percentage of replacement of 5% of the cement content. The palm fibers were weakening concrete compressive strength at different percentages and different fiber lengths. Palm leaves ash was enhancing concrete workability and concrete compressive strength. Keywords: Palm leaves Ash, Palm fibers, Replacement, Workability, Compressive strength. 1 INTRODUCTION Green concrete attracts modern research, saving the environment is the target of reducing the pollution due dangerous emissions. The cement industry is the most industry causing environmental pollution, so replacement of cement in the concrete is a very effective way to control pollution. Zeyad et al. (2017) investigated the effect of the ultrafine palm oil fuel ash on concrete strength and durability characteristics compared to ordinary Portland cement based type. Alatshan et al. (2017) discussed the possibility of using higher percentages of the replacement and longer length of the date palm tree fibers waste in concrete as a natural alternative to the conventional fibers. Two various forms of ground palm oil fuel ash were heat treated for carbon free at different levels ordinary Portland cement (OPC) partial replacements of 20, 40 and 60% to produce high strength concrete by Zeyad et al. (2018). Malkawi et al. (2019) carried out the full replacement of palm oil clicker aggregate to use it as a lightweight concrete by conducting experimental program for different replacement percentages. Azunna (2019) studied the compressive strength and water absorption capacity when replacing coarse aggregate by palm kernel shell by carrying out visual test, sieve analysis, specific gravity test, slump test, water absorption test and compressive strength test. Labib (2019) studied the feasibility of using date palm fibers in cement composites as a replacement for synthetic fibers.