Study on the preparation and mechanical and fatigue properties of alkali excited recycled concrete

Abstract

This study aims to explore the preparation process of alkali excited recycled concrete, and evaluate its performance in terms of mechanical and fatigue properties, so as to provide theoretical and practical support for the application of sustainable development and environmental protection building materials. Laboratory test and performance evaluation were used to prepare alkali-stimulated recycled concrete specimens with different proportions by adjusting fly ash, alkali activator and water solid ratio in recycled concrete. Then, the mechanical properties of the specimen were tested, including the influence of the cementing material on its compressive strength and the influence of the aggregate quality on its compressive strength. Finally, the fatigue life test is used to analyze the fatigue performance of alkali stimulated recycled concrete, and the influence of different ages and different stress levels on fatigue damage performance of alkali stimulated recycled concrete specimens is studied. The experimental results show that the mechanical properties of recycled concrete can be significantly improved by using alkali excited recycled concrete preparation technology. It is found that under the same stress ratio, with the increase of age, the corresponding fatigue life will increase, the flexural tensile strength will increase, and the fatigue resistance will improve. At the same age, the fatigue life of specimens decreases with the increase of stress ratio, and the flexural tensile strength and fatigue resistance remain unchanged. This study proves the effectiveness of alkali excited recycled concrete preparation technology in improving the mechanical properties and fatigue properties of recycled concrete. Alkali stimulated recycled concrete is not only conducive to resource reuse, reduce the impact of waste on the environment, but also provides a new choice for the sustainable development of building materials. However, further research and application are needed to promote the widespread application of alkali excited recycled concrete in engineering practice.