【作者】 董荣珍；

【导师】 马保国；

【作者基本信息】 武汉理工大学 ， 材料学， 2005， 博士

【摘要】 本文依托于国家重点基础研究发展规划（国家“973”计划2001CB610704-3）“高性能水泥制备和应用的基础研究”,针对高性能水泥制备中C₃S高活性、高含量（High C₃S content cement,简称.HCC）的关键科学问题,探讨了“973”课题组研制的水泥（本文称为973专用水泥）与传统水泥对化学外加剂兼容与调控的差异。系统研究了不同化学外加剂对HCC初始水化历程的影响规律、结构形成的作用机理和相应的调控技术路线,主要工作及成果如下: 1.水泥初始水化历程的综合性评价手段 （1）提出水泥水化初始结构形成模型采用在线检测水泥水化瞬时电性能,以电阻率描述水泥水化初始结构形成的瞬时状态。水泥水化初始结构形成分为三个发展阶段:溶解—溶解平衡期、结构形成期、结构稳定期。 （2）首次建立水泥初始水化热-电模型 运用本文建立的水泥水化初始结构形成模型,并结合水化热模型,建立水泥水化热—电模型,结合水化动力学分析,提供水泥初始水化历程的热学参数及结构形成参数,将水泥水化进程中的化学反应状态及结构形成的物理状态结合起来。 （3）建立水泥初始水化流变特性模型 采用小振幅振荡方法测试储能模量动态时间谱可准确在线检测水泥新拌浆体的流变特性,研究表明储能模量变化规律为S形变化,并且存在储能模量突变,表明水泥水化进入诱导期时存在结构突变。 2.运用热—电模型研究了典型减水剂对HCC初始水化的影响 运用热—电模型的研究结果表明:HCC对化学外加剂的适应性相对普通水泥更为敏感,这表明化学外加剂在HCC中的吸附及对水化的调控作用更为复杂,与传统水泥体系存在显著差异。平行对比实验表明973专用水泥对化学外加剂（萘系高效减水剂+减缩剂）的兼容性优于小野田水泥。对于不同种类的减水剂,新型聚羧酸盐系减水剂对HCC水化历程的调控作用较强,适应性最好。 3.聚羧酸系减水剂的合成研究 根据HCC水化特点,进行了高性能聚羧酸系减水剂（PC-23）的合成与应用研究,结果表明,研制的聚羧酸系减水剂在0.5%掺量水平下,减水率及经时流动度损失均优于国际先进产品水平,在0.15%掺量水平下,减水率及经时流动度损失均优于国内先进产品水平。与意大利产品X404平行对比研究了对水泥水化热.电性能的影响,结果表明,PC-23在对水泥初始水化的热性能及电性能的调控方面均优于X404。 4.研究了调凝剂对HCC初始水化的影响及调控作用 （1）无机盐类调凝剂的作用 无机电解质因其阴阳离子的结合方式、各自在溶液中对电荷的吸附状态而表现出对水泥水化较为复杂的影响规律,对于硫酸盐,其阳离子的种类对其在水泥水化中的调控作用具有更大的影响,更多还原

【Abstract】 This project was from of the national basic research plan ("973" project No. 2001CB 610704-3, named basic research of the production and application of high performance cement). Based on the key technology subject of it, the preparation of the high active and content C3S cement (abbr. HCC), the differences of the compatibility and control mechanism between chemical admixtures with the cement made by the "973" group and the traditional cement were discussed. Influences and mechanisms of different chemical admixtures on HCC initial hydration process and the structure forming state were studied systematically. The main achievements are listed as follows.1. Synthetically evaluating methods on the initial hydration process of cement.1) (1) To establish the initial structure forming model to describe the hydration process of cement. The instantaneous electrical property of cement hydration is evaluated through online examination and the instantaneous state of initial structure formation was characterized by resistivity method. The initial structure forming model of cement includes three stages, i.e. solution-solution equilibrium stage, structure forming stage and structure stabilizing stage.2) To establish the Heat-Electric Model (abbr. H-E model) of the initial cement hydration for the first time. This model is built through the combination of the initial structure forming model and the setting heat model. The H-E model provides the thermal parameter and the structure forming parameter of cement initial hydration process, which combines the chemical reaction course and physical state of the structure forming.3) To establish the rheological property model of initial cement hydration. By the way of short-swing surge, the storage modulus model of cement behaves as "S". There was a sudden change on structure forming when the hydration of cement turns into the inducing period.2. The effects of typical water reducers on initial hydration of HCC were studied by the H-E model.Results show that the compatibility problems of chemical admixture and HCC are more obvious than those of the ordinary cement. For HCC, the special cement of’973’ is better than Taiheiyo cement on compatibility with chemical admixtures and the strength, especially early strength. For different water reducers, the compatibility between polycarboxylate superplasticizer and HCC is the best among of them.3. Synthesis study of polycarboxylate superplasticizer.The product, named as PC-23, is synthesized successfully. The rate of water reduced is equal to that of the X404, the best product in the world, when used at the lower dosage. The examination results of H-E property of hydration process show that the PC-23 is better than X404.4. Influence of setting adjustment agents on initial hydration of cement.1) Action of electrolyte on initial hydration of cement.The combining style and the absorption to electricity in solution of cation and anion of electrolyte are complicated, which makes the cement hydration very complicated. For sulfate, the kind of cation influences the control on hydration process greatly. Along with the increasing of atomic number, the action on cement hydration turns from setting promoting and early strength enhancing to setting retarding.For the same cation, different acid radical makes the action on cement hydration different. Both ZnCb and ZnSC>4 retard the hydration process of cement, Cl~ may promote the setting retarding function of Zn2+, while the effect of ZnSC>4 is much smaller and shows the critical effect with the change of mixing mass.For sodium salts with different phosphate, the effect on setting retarding is different greatly according to different acid radical. The influence mechanisms of Na3PC?4, Na2HPC?4 and NaH2PC>4 are accordant, i.e. forming the calcium phosphate and retarding hydration. For NasPaOlo, the complex is formed by absorption with Ca2+ and makes the retarding function strongest among of them.2) Effects of organic setting retarders.The influence regulation of organic retarders on cement hydration heat process can be described as a saddle dual-peak phenomenon and becomes more obvious with the increasing of mixing amount. Cumulating quantity of heat at 1-day hydration age decreases at first time and increases at later, demonstrating the accelerating hydration process. Resistivity curve shows that structure formation becomes worse with the increasing of mixing amount, which is consistent with the strength development trend.There exists dual-critical effect of organic retarders on cement hydration. First, cement hydration is delayed when the amount is low, while accelerated when the amount is comparatively high. But paste is not hardened even after a long time under the latter situation. Secondly, there exists a critical amount of setting retarding. When it is lower than that,retarding effect increases with the enhancement of amount. While it is higher, retarding effect decreases with the enhancement of amount. This effect is more prominent for high C3S content cement, and the amount range of organic retarders is narrower than that in traditional cement.3) Control technology of HCC-chemical material system.Results show that the adoption of current technic method by application of HCC material will lead the decrease on damp and increase of the loss of damp with time elapsing. It can be resolved the methods as follows: ?composite of chemical admixtures, (2) increasing the dosage of chemical admixtures(0.05%-0.1%) because of the excursion of the saturation, (Dusing the chemical admixtures with extensive applicability.5. To establish the counter-percolation model of cement initial hydration for the first time.1) The counter-percolation process of cement initial hydration.It can be considered that two qualities leaps (or call it as segment) exist in the cement hydration process by onling examination of the change of resistivity and storage modulus along with it, i.e. a) Change from fluidity to plasticity; b) Change from plasticity to harden solid.Through the above two mutations along with it, the cement hydration process can be described as the process from existing of percolation passage to being filled little by little. Two critical thresholds appeare in the filling process, i.e. G’threshoid according to pmjn (not completely consistent on time) and puireshoid (may be more reasonable expressed as the critical segment). Therefore cement hydration process is the counter-percolation process, and a gradating process from fluidity to harden solid2) Relationship between the eigenvalue of resistivity and strength is built.Results show that all data can be classified by p24 and pmjn. The relation between p24 and strength is logarithmic. At 1-day age of hydration, the structure of cement stone has been formed (except for the super retarding situation); while the characteristic of microstructure at this time is closely relative to the physical-mechanical property and durability for long term. Therefore P24 expresses a better relativity with strength.The data group can be classified as two subset (subset A and subset B) by pmjn. Data in subset A are mainly chemical admixtures with setting retarding function, and the dosage in cement is relatively bigger. Data in subset B are mainly inorganic chemical admixtures, and organic admixtures in it are the results at lower mass.The relation between resistivity eigenvalue and strength is linearity in subset A. the action mechanism on cement hydration of them has common characteristic, which plays an important role in the structure forming process. The two critical thresholds express better relativity with strength by analysis of data in subset B. The structure forming state from adding water to pmin and from the end of solution - solution equili- brium stage (induce period in thermal model) to pthreshoid is closely relative to the physical- mechanical property of cement. The instantaneous state of resistivity in the cement hydration process gained by non-contacting electrical resistivity device can describe this course very efficaciously, which proves the counter-percolation process of cement hydration process along with the mutation of resistivity.更多还原