Effects of eggshells powder and date seeds on properties of sustainable concrete.

Nowadays, there is an urgent need to search for alternative materials such as concrete ingredients; therefore, various natural materials such as organic wastes have been explored. Iraq produces a lot of organic and agricultural wastes that are largely unused. This study conducted an experimental investigation to evaluate the suitability of incorporating eggshells powder and Date Seeds (DS) in concrete. Concrete mixtures including 10% eggshells powder as a replacement by weight of cement in combination with different contents of DS of 0, 15, 25, and 35% as volume replacement to natural coarse aggregate. In addition, a reference concrete mixture without eggshells or date seeds was prepared (M). The features considered were flexural and compressive strengths, workability, dry density, permeability, thermal conductivity, and water absorption. The results illustrated that the optimal replacement content is 15% replacement of date seeds as volume fraction of natural coarse aggregate in the concrete. This content reduces thermal conductivity, flexural strength, and compressive strength, by about 6%, 9.81%, and 19.37%, respectively, compared to the concrete mixtures containing only eggshells powder at 28-day age. Furthermore, the water absorption and permeability of DS concrete were increased whenever DS level ascended, but permeability and water absorption values were lower than 10% and 50 mm, respectively, which indicate the good quality of this concrete. This investigation demonstrates that eggshells powder and date seeds can be successfully used as waste materials to produce high-strength, sustainable concrete with acceptable properties. [ABSTRACT FROM AUTHOR]