高强高抗蚀地聚合物基珊瑚混凝土微结构形成机制

Use of local raw materials is extremely necessary for the offshore island construction in the ocean. Currently due to the unstability of cement hydration products under the ocean environment, low strength of coral aggregates, and weak interface microstructure between the cement matrix and coral aggregates, the conventional coral concrete exhibited low strength and poor corrosion resistance. This study aims to design and prepare geopolymer based coral concrete with high strength and high anti-corrosion property under the ocean environment via using the geoplolymer binder and the specially treated coral aggregates. The evolution of composition and microstructure of geopolymer at nano-scale under the effects of various oceanic factors and its impact on the performance will be investigated to reveal the mechanism of microstructure degradation and the microstructure characteristic of stable geopolymer. The coral aggregates will be treated via micro-chemical corrosion and vacuum grouting with geopolymer as the grouting materials, and the formation mechanism of the new composite structure formed in the geoploymer treated coral aggregates and the corresponding control approaches will be demonstrated. The effects of anti-corrosion improved geopolymer binder, interface enhanced coral aggregates, and the inner curing on the performance of geoploymer based coral concrete will be examined to disclose the intrinsic relationship between the microstructure evolution and macro-property development of concrete under the effects of various oceanic factors. Based on this, the mechanism of microstructure formation of geopolymer based coral concrete with high strength and strong corrosion-resistance will be revealed. The study will provide a theoretical guide and technical supports for the preparation of high performance structural materials of geopolymer based coral concrete used for the offshore island construction in ocean.

远洋岛礁工程采用珊瑚等“就地取材”建设是必然追求。现有水泥基珊瑚混凝土因其水泥水化产物在海洋环境下稳定性差，珊瑚骨料强度低，且界面过渡区结构弱，故强度低、抗蚀性差。本项目针对远洋岛礁环境，探索利用地聚合物胶凝材和改性珊瑚骨料设计制备高强高抗蚀地聚合物基珊瑚混凝土。研究不同海洋因素作用下地聚合物纳微米尺度组成与结构的演变规律及其对性能的影响，探明其微结构劣化机理及长期稳定的地聚合物结构特征。以地聚合物为灌浆材料，采用化学微腐蚀和负压灌浆等技术对原状珊瑚进行改性处理，阐明地聚合物改性珊瑚骨料复合结构形成机制和调控方法。研究地聚合物胶凝材的抗蚀增强和改性珊瑚骨料的界面增强及内养护效应对珊瑚混凝土性能的影响，探明不同海洋因素作用下混凝土微结构演变与宏观性能的内在关系，探索出高强高抗蚀地聚合物基珊瑚混凝土微结构形成机制。成果将为远洋岛礁环境高性能珊瑚混凝土结构材料设计与生产提供理论指导和技术支撑。

“提高海洋资源开发能力，坚决维护国家海洋权益，建设海洋强国”已成为国家新的战略，海洋工程混凝土是发展海洋经济的重要基础支撑。远洋岛礁工程是土木工程中最具挑战性的领域。在不破坏当地生态环境前提下，利用岛礁中珊瑚礁制备粗细集料，就地取材配制高性能珊瑚混凝土，这对于海岛军用和民用工程建设具有极其重要的意义。现有珊瑚混凝土存在抗蚀差和强度不足等问题，而严酷环境下传统胶凝材料稳定性差、珊瑚骨料连通孔隙率大强度低、界面过渡区弱是影响其性能的根本原因。本项目针对远洋岛礁环境，从新型胶凝材料和珊瑚骨料角度入手，利用地聚合物胶凝材和改性珊瑚骨料设计制备出了高强（抗压强度＞60MPa）高抗蚀（氯离子扩散系数＜3.0×10-12m2/s）地聚合物基珊瑚混凝土。研究了不同海洋因素作用下地聚合物纳微米尺度组成与结构的演变规律及其对性能的影响，探明了其微结构劣化机理及长期稳定的地聚合物结构特征。采用化学微腐蚀和地聚合物裹浆等技术对珊瑚骨料进行改性处理，去除其表面附着物、降低内部连通孔隙率及提高其强度，阐明了地聚合物改性珊瑚骨料复合结构形成机制和调控方法。探究了不同海洋因素作用下混凝土微结构演变与宏观性能的内在关系，探索出了高强、高抗蚀地聚合物基珊瑚混凝土微结构形成机制。掌握了利用地聚合物胶凝材和改性珊瑚骨料设计制备高强高抗蚀地聚合物基珊瑚混凝土的关键技术与方法。研究成果可为远洋岛礁环境高性能珊瑚混凝土结构材料设计与生产提供理论指导和技术支撑。