Partial Replacement of Cement with Agricultural Waste (Palm Ash) to Improve the Concrete Properties

Recently, many pozzolanic materials resulting from industrial and agricultural wastes, such as palm ash, have been used to improve the properties of concrete and reduce cement use. This research investigated the preparation and replacement of palm ash by the weight of cement and its impact on the properties of fresh and hardened concrete. Two types of palm ash, namely palm frond ash (PFA) and palm frond base ash (PFBA), were prepared using fronds and frond bases. The replacement proportions for each type of palm ash were 0%, 5%, 10%, 15%, and 20% by weight of cement. The results indicated that the initial and final setting times increased, and the slump of the concrete decreased as the content of PFA and PFBA increased. The compressive, splitting, tensile strength, and static modulus of elasticity of PFA and PFBA-concrete improved with curing at 7, 28, and 90 days, with the 5% replacement. Higher ash inclusion reduced the mechanical properties at early ages. The development of strength with age was evident in the scanning electron microscope (SEM) images, where the microstructure of PFA20 was denser than that of the control mix. Except for the 5% PFA replacement, all other mixtures exhibited slightly higher water absorption.