微量组分复合掺杂对贝利特-硫铝酸钡钙水泥熟料矿相微结构及水化活性的影响

Belite-rich cement is advantageous of low sintering temperature, longterm-high strength, good resistance to corrosion, applicability of low grade limestone and low emission of CO2. However, its bad shortage is the early-low strength. We have introduced barium calcium sulphoaluminate mineral which is characteristic of rapid hardening and high early strength into belite-rich cement, and thus belite-calcium barium sulphoaluminate cement clinker could be synthesized at a low calcination temperature. Although the cement clinker has shown improved early-strength, it still can not meet the requirements for construction. In this project,composite minor components such as BaO, SrO, MgO and SO3 are to be introduced into the belite-calcium barium sulphoaluminate cement clinker in composite . It is expected that the microstructures of belite and alite minerals can be tuned to be polymorphous via the combination of the doping, cooperative effects of the minor components distributed in the mineral phases of clinker and the adjustment of thermal operation conditions. Thus, the minerals could have high activity and the early strength of the cement can be further enhanced. The main research contents include: the synthesis, optimization of mineral phases, physical and chemical properties of the belite-calcium barium sulphoaluminate cement clinker with the addition of minor components; the influence of minor components on the microstructure and microstructure evolution of the belite and alite minerals as well as the controlling mechanism; the mechanistic study of the influence of the added minor components on the early hydration activity and velocity of the belite and alite minerals. The research will lay foundations for integrating a theoretical and technical system of the belite-calcium barium sulphoaluminate cement.

高贝利特水泥具有煅烧温度低、长期强度高、抗腐蚀、可利用低品质石灰石和CO2排放量低等特点，但其最大缺点是早期强度低。项目组在高贝利特水泥熟料中引入了快硬早强型矿相-硫铝酸钡钙，在低温煅烧条件下合成了贝利特-硫铝酸钡钙水泥，使其早期强度有所提高，但仍不能满足建筑工程要求。本项目是在贝利特-硫铝酸钡钙水泥熟料矿相体系中复合引入BaO、SrO、MgO、SO3等微量组分，通过微量组分在熟料矿相中的复合掺杂作用和协同效应，并结合热工制度变化，调控熟料中贝利特和阿利特等具有多晶变体特性矿相的微结构，使其处于高活性结构状态，促进其水化并提高早期强度。主要研究内容：掺杂微量组分条件下贝利特-硫铝酸钡钙水泥熟料的合成、矿相组成体系优化及性能研究；微量组分对贝利特和阿利特矿相微结构的影响及结构演变和调控机制研究；微量组分对水泥早期水化活性和水化速率的影响机制及时效性研究。为完善该水泥的理论与技术体系奠定基础。

高贝利特水泥具有煅烧温度低、长期强度高、抗腐蚀、可利用低品质石灰石和CO2排放量低等特点，但其最大缺点是早期强度低。项目组在高贝利特水泥熟料中引入了早强型矿相-硫铝酸钡钙，使其早期强度有所提高，但仍不能满足建筑工程要求。本项目是在上述贝利特-硫铝酸钡钙水泥基础上，复合引入BaO、SrO、MgO、SO3等微量组分，通过掺杂作用和协同效应，调控和稳定熟料中贝利特和阿利特等矿相的高活性微结构，进一步提高水泥早期强度，获得如下结论：明确了微量元素对贝利特和阿利特高温形成和水化活性的影响机制，确定了微量元素对硅酸盐矿相形成量和微结构的调控机制；确定了微量组分和液相组成对贝利特-硫铝酸钡钙水泥熟料主矿物晶型和熟料组成的影响规律，获得了微量元素作用下水泥熟料的适宜合成制度；获得了水泥具有突出早期力学性能时微量元素掺杂组合和掺量。明确了柠檬、磷和脱硫石膏可作为该水泥的缓凝剂，Na2SO4、Ca(NO3)2和Ca(HCOO)2可作为该水泥的早强剂，聚羧酸、萘系、脂肪族可作为该水泥减水剂，并获得了上述外加剂的适宜掺量；最终获得了微量元素掺杂条件下具有良好早期力学性能的熟料矿相体系的匹配关系，建立了微量组分掺杂对熟料中贝利特和阿利特等矿相微结构的调控机制。