碱激发矿渣的微结构表征、优化及其与宏观行为的关系

Alkali Activated Slag (AAS) is a hydraulic binding material which possesses good mechanical performance as well as good frost resistance, sulfate resistance, etc, without the addition of any cement clinker. However, the application of AAS as construction materials so far has been very limited due to its large shrinkage and tendency to carbonate when used in civil engineering. This has been mainly attributed to the shortcomings at the microstructural level of AAS when compared with Portland cement paste. Accordingly, this project will investigate the microstructure and mechanical performance of C-S-H, which is the major hydration product of AAS. Nano materials will be chosen to optimize the microstructure of AAS. Factors, such as raw materials and their proportion, temperature and humidity, curing age, concentration of CO2, will be examined to clarify their impact on the microstructure and mechanical performance of AAS with and without nano materials. Consequently, by incorporating the results at macro level, the relation between the microstructure and the macro properties, especially shrinkage and carbonation, will be established, and a prediction model will be put forward to quantify the relation between microstructure and shrinkage. Theory and novel technology, to be derived from the achievement of this project, will surely help solve the shrinkage and carbonation problem of AAS for application as major construction materials. It is not unreasonable to believe that the application of AAS in civil engineering will expand and hence the bondage to traditional Portland cement will be greatly loosened.

碱激发矿渣是一种水硬性、无水泥孰料的新型胶凝材料，具有优异的力学性能、抗冻融、耐硫酸盐腐蚀等耐久性能。但收缩大、易碳化等问题严重阻碍了其在土木工程领域的推广应用。根本原因在于，与硅酸盐水泥浆体相比,碱激发矿渣水化产物存在明显的微结构缺陷。因此，本项目拟从碱激发矿渣水化产物C-S-H凝胶的结构和微观力学性能着手开展研究。在充分掌握凝胶结构及性能的基础上，优选纳米材料对碱激发矿渣的微观组成和结构进行优化，并揭示原材料组成和配比、温湿度、龄期、碳化等条件对其微观组成、结构和微观力学行为的影响规律、微结构形成机理，以及微结构与宏观性能（特别是收缩和碳化）的关系，提出基于微结构定量表征的收缩预测模型。研究成果将为解决碱激发矿渣在土木工程中应用中遇到的收缩大、易碳化等问题提供新的理论方法和技术途径，从而扩大在土木工程结构中的应用，减少土木工程材料领域对硅酸盐水泥的依赖。

碱激发矿渣是一种水硬性、 无水泥孰料的新型胶凝材料， 具有优异的力学性能、抗冻融、耐硫酸盐腐蚀等耐久性能。但收缩大、易碳化等问题严重阻碍了其在土木工程领域的推广应用。本项目通过采用纳米材料，纤维及膨胀剂对碱激发矿渣进行了改性。通过对水化产物微结构变化的表征探究了纳米材料在碱激发矿渣体系中的作用机理；采用不同品种的纤维改善碱激发矿渣的收缩性能，并研究了碱激发矿渣内部湿度与自收缩之间的内在联系;研究了不同品种的膨胀剂对碱激发矿渣的内部湿度和干燥收缩的影响及相关关系，解释了膨胀剂在碱激发矿渣体系中的作用机理；采用了不同的测试方法表征了碱激发矿渣在不同预处理条件下的碳化行为，为提高碱激发材料的碳化试验的准确性提出了新的预处理方法。