水泥基材料匹配水化及匀质结构形成的控制机理

There is a big difference in the aspect of hydration activity, products and hardening characteristics among different clinker minerals, and between the clinker and auxiliary cementitious materials. It leads to uneven distribution of the products and uncompacted microstructure of hardened cement paste, and restricts the performance of cement-based materials to further improve.In order to further improve the strength and durability of cement-based materials to meet the need of long safety working age and extreme working condition, it must be to design, optimize and control the microstructure of cement-based materials. Therefore, it is put forward by our present project to study the controlling mechanism of matching hydration among the components of cement-based materials and the formation of homogeneous structure of hardened paste. These measures, the control of clinker mineral composition and hydration activity, the fineness and particle size distribution of the finely ground clinker and auxiliary cementing material and its matching, induced hydration and activity stimulation, are taken in order to better matching hydration among different clinker mineral, clinker and auxiliary cementing materials and producing the mutually beneficial synergy during the hydration and hardening process of the cement-based material, thereby achieving the aim to control the formation, morphology, dimensions, distribution and accumulation of the hydration products, and obtaining continuous, homogeneous and compact hardening structure. Through the studies in the project, the optimal clinker mineral composition and design principles based on matching hydration and homogeneous structure will be confirmed. The influence rule of the optimal matching of fineness and particle size distribution between common auxiliary cementing material and clinker, activity stimulation and pretreatment, temperature and pH on the matching hydration and the microstructure and performance will be explicit. The approach and mechanism to induce hydration and hardening will be.mastered. The matching principle of hydration among different clinker mineral, auxiliary cementing materials and clinker will be explicit. The evolution law of cement-based material microstructure under matching control will be revealed and the mechanism to control homogeneous microstructure formation will be established.

水泥基材料中不同熟料矿物及熟料与辅助胶凝材料之间，在水化活性、产物和硬化特性方面存在较大差异，导致硬化浆体中产物分布不均匀、堆积不密实，直接制约着性能进一步提升。若要较大幅度提升其性能，须从更微观尺度控制硬化体结构的形成。本项目提出，通过调控熟料矿物水化活性匹配、纳米晶种或粒子诱导水化、石膏溶解特性、熟料与辅助胶凝材料颗粒组成匹配、化学助剂及活性激发等措施，使水泥基材料各组分实现匹配水化，不同组分之间产生有利的协同效应，达到控制水化产物的生长与分布，使各种产物更加合理的交错连生、紧密堆积，形成高度均匀致密的硬化体结构，进而显著提高其力学和耐久性能。通过探明不同熟料矿物共同水化硬化时的协同效应，揭示水泥基材料匹配水化及其调控机理，掌握匹配水化下硬化体结构演变规律，建立结构演变模型和控制机制。提升水泥基材料的力学和耐久性能，为实现水泥基材料性能的设计性、可控性提供理论基础。

水泥基材料中不同熟料矿物及熟料与辅助胶凝材料之间，在水化活性、产物和硬化特性方面存在较大差异，导致硬化浆体中产物分布不均匀、堆积不密实，直接制约着性能进一步提升。本项目针对水泥基材料中的不同熟料矿物及熟料与辅助胶凝材料之间的水化活性、产物和硬化特性的不同机制，从更微观尺度控制硬化体结构的形成。首先针对熟料的主要矿物C3S、C2S、C3A和C4AF，从单矿物着手，系统研究了两种、三种或四种矿物共同水化时相互间水化速率、水化产物生长与分布、硬化体结构与性能等的协同规律，揭示了熟料矿物之间的匹配水化关系。根据矿物匹配水化的研究结果，设计了不同的熟料矿物组成，通过研究不同组成对匹配水化以及硬化体结构形成和性能的影响规律，提出了基于匹配水化和硬化体结构均匀性与致密性的最佳熟料矿物组成为C3S：C3A：C4AF约为8.6：1.0：1.1。进而开展了纳米晶种、减水剂以及不同种类石膏对熟料矿物匹配水化的影响规律的研究，结果表明，纳米SiO2可促进C3S水化，抑制C3A和C4AF的水化，并改善微结构；聚羧酸减水剂也具有抑制C3A和C4AF水化、促进C3S的水化的作用；二水石膏对熟料水化的调节作用明显，而无水石膏更有利于致密微结构的形成。在此基础上，开展了多因素协同对水泥基材料水化硬化历程、水化产物生长与分布，孔结构与分布以及力学与耐久性等的影响研究，基于匹配水化原理优化水泥基材料的组成设计，探讨水泥基材料硬化体结构与性能的演变规律，揭示了多因素协同调控水泥基材料结构与性能的机制。建立了UHPC紧密堆积模型，确定了28d抗压强度达165Mpa的最佳组成。.本项目研究成果，为进一步提升水泥基材料的力学和耐久性能，实现水泥基材料性能的设计性、可控性提供理论基础。

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