performance of grape extract addition as an admixture in concrete construction

Chemical admixtures are widely used for the production of high-performance concrete, but they are responsible for environmental pollution and health issue during construction because of their chemical nature. also manufactured admixtures are expensive, on this base recently, researches and attempts are focused to find alternatives, and using different natural or bio admixtures for concrete is a good choice. in this study, the impact of grape extract (ge), a natural additive, on the properties of concrete was investigated. various ge percentages were used to investigate the properties of fresh and hardened concrete. the results show that there is a continuous workability enhancement and continuous splitting tensile strength loss with ge increase.  improvement of 28 days compressive strength by 18.5% was observed on using 0.22% ge, while no compressive and flexural strengths loss was observed with ge addition up to 0.55%. finally, the results of the study showed that ge dosages can strongly impact the fresh properties and mechanical strength of concrete mixtures. so there is a chance to produce self-compacting concrete using ge natural admixture instead of chemical admixture but there is a need for further experimental tests.