Effects of palm fronds fibers on properties of high-volume fly ash concrete

Portland cement concrete is considered as the most difficult product in environmental pollution, although it is the main construction material. One of the alternatives is high volume fly ash concrete which uses low cost binding material (waste material) as a high replacement to Portland cement. This type of concrete is brittle similar to traditional concrete. So, the aim of this research is to use organic fibres (palm fronds fibres), which is a waste material, in enhancing the tensile property of this concrete (that use 50 % and 60 % replacement of fly ash). The percentages of fibres used are 0.4, 0.8, 1.2, 1.6, and 2% by volume of concrete to find the optimum percentage of it. The effects of fibres were studied on dry density, compressive and tensile strength, and drying shrinkage upto 90 days age. Results indicate that the optimum percentage of palm fronds fibres that can be added to high volume fly ash concrete (with 50 or 60% replacement of cement by fly ash) is 1.2% by volume.