基于球形吸水树脂集料的混凝土设计、制备及其性能研究

The concrete preparation for far sea engineering is quite important for the national sea exploration strategy. This project proposed concrete design and preparation method based on the spherical super absorbing polymer aggregate as replaced aggregate, which to prepare concrete for far sea project with less quantity raw materials . By studying the volume and properties change rule during absorbing and releasing water process, the method to control its size was invented. By studying the aggregate’s water releasing kinetics and its inducing mechanism and control methods, the compatible binding materials were designed. By studying the pore with arch roof structure forming mechanism in the concrete, the quantitative relationship among strong arch shell structure with high strength pore wall, porous rate and the mechanical behavior of concrete was established to build the calculation model of high strength concrete. The methods to form the specific arch roof structure were invented. The physical and durability properties of concrete were studied and the structure degradation mechanism was revealed. The design method of high performance concrete base on the super absorbent polymer aggregate was proposed. The research not only could support the building materials in lack of special geographical aggregates (far sea) area, but also proposed a method to control and design the pore structure in concrete, which has important scientific significance to enrich and improve the preparation and design theory of high performance concrete material.

随着国家海洋重大战略的实施，开发适用于远海岛礁工程的混凝土材料具有重要意义。项目利用球形树脂吸水膨胀的特性制备弹性球珠取代集料，从而实现远海岛礁工程混凝土减量化制备。通过研究球形树脂吸-释水过程中的体积变化与性能变化规律，提出树脂基弹性球珠集料粒径的控制方法；研究树脂集料在水泥浆体中水分输移动力学及其释水诱发机制与控制方法，设计与其相匹配的胶凝材料体系；研究球形树脂集料释水形成拱壳结构的机理，探明拱壳结构特征与混凝土力学性能的关系，提出特定高强拱壳结构的构筑方法；系统研究该类混凝土的物理力学性能与耐久性，探明其结构损伤与性能劣化机制，提出基于球形树脂集料的岛礁工程混凝土材料的设计与制备方法。研究不仅对于远海等集料缺乏特殊地域的建筑需求具有重要支撑作用，同时提供了混凝土内部孔结构设计与调控新思路，对丰富和完善水泥混凝土材料设计制备理论具有重要科学意义。

项目基于球形树脂吸水体积膨胀-释水养护的特性制备弹性球珠取代集料，实现远海岛礁工程混凝土的减量化制备，满足远海岛礁等集料缺乏地域的建筑需求。项目的主要研究内容包括：树脂集料与胶凝材料匹配设计及其制备方法；高强拱壳结构形成机理及对混凝土力学承载特性的贡献机制；侵蚀介质作用下树脂集料混凝土的结构损伤劣化机制与耐久性设计。项目探明了吸水树脂集料在水泥浆体中的释水机理：SAP在混凝土内部的释水过程主要受渗透压及湿度差的影响，毛细管压力则主要起水分传输作用；SAP早期释水主要受混凝土内部离子浓度差引起的渗透压影响，而后期释水主要受湿度差影响，并影响高强拱壳结构的形成。采用SAP的水分含量变化直接量化了SAP与水泥浆体之间的水分迁移交换过程，推导并建立SAP内部水分在不同阶段的释放比例及内养护水有效利用率评价方法，提出缩短早期渗透压释水过程，延长后期湿度差释水的原则，以提高SAP内养护水有效利用率，从而实现高强拱壳结构的构筑。揭示了球形树脂集料释水后形成的拱壳结构界面过渡区的结构特征，探明了高强拱壳结构对混凝土力学承载特性的贡献机制。高强拱壳结构的界面区水化程度比基体处约高5%，且相当于0.04附加水灰比带来的水化效果， SAP没有改变界面区孔形态特征，但其释水行为会在水化前期明显增大界面区的孔隙量，后期养护作用使界面区孔隙量最终低于基体处。提出树脂基弹性球珠集料粒径的控制方法，制备了不同密度与强度等级的吸水树脂集料混凝土，研究了其物理力学性能、吸声降噪隔热等功能特性以及耐久性。最后，提出了吸水树脂集料混凝土的设计原则，即在满足内养护理论需水量的前提下，以接近于SAP在初始水泥浆体中的平衡吸水率设计内养护引入水倍率，使SAP在新拌浆体内部稳定存在，并最大程度减小其对力学性能的负面影响。本项目研究成果对于促进内养护混凝土理论与技术进步，推动内养护混凝土的实际工程应用具有重要意义。