大掺量矿物掺合料在蒸养混凝土中的作用机理

预制混凝土技术是实现建筑工业化的重要技术之一，蒸养工艺是预制混凝土技术的核心技术。矿物掺合料已在预拌现浇混凝土中得到广泛应用，但在蒸养混凝土中的利用率较低。将大掺量矿物掺合料应用于蒸养混凝土中，可以推动蒸养混凝土走向"低碳"发展，且矿物掺合料在蒸养条件下更能发挥其作用，并能够改善蒸养混凝土的一些性能。本申请项目将根据复合胶凝体系初期水化性能与最佳预养时间的关系，探索大掺量矿物掺合料对蒸养混凝土的最佳预养时间的影响机理；根据蒸养条件下矿物掺合料的活性与蒸养温度的关系，探索大掺量矿物掺合料对蒸养混凝土的最佳蒸养温度的影响；揭示含大掺量矿物掺合料的蒸养混凝土的宏观性能和微结构的发展规律；揭示蒸养条件下大掺量矿物掺合料在水泥基复合胶凝体系水化硬化过程中的作用机理；探索大掺量矿物掺合料对蒸养混凝土的后期开裂风险的影响和机理。本申请项目的研究成果对在蒸养混凝土中使用大掺量矿物掺合料提供理论基础。

Precast concrete technology is one of the key technologies for the realization of construction industrialization. Stream curing is the key technology of precast concrete technology. Mineral admixtures are widely used in cast-in-site concrete, but their utilization ratio in stream cured concrete is very low. The application of high-volume mineral admixture to stream cured concrete can promote its low-carbon development. In the meanwhile, mineral admixtures make more contribution to the concrete under stream curing condition, which might improve some properties of stream cured concrete. This project will investigate the influence mechanism of high-volume mineral admixture on the optimum pre-curing time based on the relationship between initial hydration properties of complex binder and the optimum pre-curing time. It will also investigate the influence mechanism of high-volume mineral admixture on the optimum stream curing temperature based on the relationship between the activity of mineral admixture and the curing temperature. The developing law of microstructure and macro-properties of stream cured concrete with high-volume mineral admixture, and the role of high-volume mineral admixture in the hydration and hardening process of cement-based complex binder will be revealed. The influence of high-volume mineral admixture on the cracking risk of stream cured concrete at late ages will be investigated. The results of this project will provide theoretical basis for the application of high-volume mineral admixture to the stream cured concrete.