The main objective of this research investigation is to study the effects of Olive Mill Waste (OMW) ash and Normal Coal (NC) ash on some engineering properties of normal strength concrete such as workability and compressive strength. This follows a worldwide desire for more sustainable concrete mixes utilising such wastes. A more environmentally-friendly approach would reduce the cement content in a concrete mix and replace it by wastes. Overall, there are numerous benefits associated with the recycling of such waste products for the provision of a substitute concrete mix. Firstly, replacing a certain amount of cement with OMW and NC ash would reduce the overall cost of the concrete mix. Additionally, recycling theses wastes would decrease the levels of pollution which would otherwise increase the spread of pests and negatively impact the health of the population. As well as aiding the achievement of a cleaner environment, regenerating these wastes for the purpose of creating a concrete mix would eliminate the costs of their disposal. In order to achieve this goal, different percentages e.g. 10, 20, 30 and 40% of both OMW ash and NC ash were used as an additive and/or replacement in the production of normal concrete strength mixes to obtain a concrete grade of 40 MPa. Four sets of concrete mixes were cast to test the workability and the compressive strength based on the changes of the percentage of OMW and NC ashes by weight of cement. The slump test results ranged from 58 to 110 mm with the addition and/or replacement of OMW and NC ashes. Moreover, the compressive strength is decreased as the percentage of adding and /or replacement of OMW and NC ashes is increased.
