Ecological and energetic optimization of concretes: Challenges in the processing of calcined illitic and smectitic clays - solution approaches using tailor-made superplasticizer structures

混凝土的生态和能量优化：煅烧伊利石和蒙脱石粘土加工中的挑战 - 使用定制超塑化剂结构的解决方案

• 批准号: 314833927
• 负责人: Professor Dr. Johann Plank
• 金额: --
• 依托单位: Institut für Werkstoffe des Bauwesens
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/314833927?language=en
• 关键词: Ecological; energetic; optimization; concretes; Challenges

In the preceding project, it was found that while metamuscovite and metakaoline can be fluidized well, it was however impossible to disperse metaillite with conventional polycarboxylate superplasticizers.For this reason, in the present submission the focus is on the behavior of calcined illite with respect to its chemical-mineralogical properties and its surface structure after calcination. Apart from a physical characterization, comprehensive mineralogical investigations (particle size & morphology, water sorption capacity, cation exchange capacity, zeta potential) are planned to capture its surface properties (layer charge). Utmost attention will be given to the development of the surface charge in the cementitious system. For this purpose, zeta potential measurements will be carried out especially in a pore solution in which ions taken up by the calcined clay will be replenished immediately. This way, the actual surface charge existing in cement can be assessed under equilibrium conditions (saturated adsorption). Based on these data, the spatial distance between Ca2+ ions adsorbed on the surface of the calcined clay can be calculated. Relative to this subject, a cooperation with the institute for “Applied mineralogy/Clay science” at KIT (Dr. Emmerich) is planned to incorporate the well-known expertise of this research group on illitic clays into this project.Because illite often occurs as mineral interstratified with smectite clay it is planned to study such mixed layer clay and pure smectite as well. This series from metaillite → metaillite-smectite → metasmectite should allow to develop a model describing the specific mineralogical changes within this sequence.The second part of the project addresses the rheological properties of the calcined clays as well as their interaction with superplasticizers. Based on the findings on the surface structure and charge, tailor-made superplasticizers shall be synthesized which according to a steric analysis of the molecular geometry of their functional groups can form a complex with Ca2+ ions sorbed on the surface of the calcined clay. For this purpose, MPEG-, APEG- and HPEG-based polycarboxylates with varied spatial distance between the carboxylate groups, an amphoteric as well as sulfonated and phosphated comb polymers will be synthesized and tested. To achieve certain structures, entirely new synthesis routes incl. RAFT/ATR polymerization may need to be developed. This way, a profound understanding of why conventional superplasticizers cannot fluidize metaillite, and which specific molecular parameters are required to achieve such fluidizing effects shall be achieved.The fluidizing effect of the optimized superplasticizers shall be evaluated further via rotational viscosimetry. Finally, for an in-depth understanding of the interaction superplasticizer-cement-calcined clay it will be investigated via pressure filtration whether the polymers adsorb preferentially on cement or on the calcined clay.

在上一个项目中，发现元曲霉和梅塔牛林可以很好地流动，但是不可能用常规的聚碳酸超塑料剂分散元硅酸盐。出于这个原因，在当前提交中，焦点是钙化的伊利特行为，而对其化学矿物学性质及其表面结构进行了计算。除了物理表征外，还计划综合矿物学研究（粒度和形态，水溶液能力，阳离子交换能力，Zeta电位）以捕获其表面特性（层电荷）。最大的关注将引起水泥系统中表面电荷的发展。为此，将在孔隙溶液中进行ZETA电位测量，尤其是在孔隙溶液中，将立即更换钙化粘土的离子。这样，可以在平衡条件下（饱和吸附）评估水泥中存在的实际表面电荷。基于这些数据，可以计算在计算出的粘土表面吸附的Ca2+离子之间的空间距离。相对于这个主题，计划将这个非法粘土研究小组的众所周知的专业知识纳入该项目。由于伊利石通常是在矿物质与绿色粘土相交时发生的，因此也计划研究这种混合层粘土和纯绿铁矿。来自元硅氧石→元硅石 - 丝岩→丙咪酸酯的系列应允许开发一个描述该序列内特定矿物学变化的模型。该项目的第二部分涉及钙化粘土的流变特性以及它们与超级塑料的相互作用。根据对表面结构和电荷的发现，应合成量身定制的超塑剂，根据其官能团的分子几何形状，可以形成一个复合物，在钙化粘土表面上吸附的Ca2+离子。为此，将合成并测试基于MPEG，基于HPEG和HPEG的聚苯甲酸盐，其空间距离各不相同，将合成和测试，两性以及硫化和磷酸化的梳子聚合物。为了实现某些结构，全新的合成路线包括。可能需要开发RAFT/ATR聚合。这样，应深刻理解为什么传统的超塑剂不能流化元硅氧石，以及需要哪些特定的分子参数才能实现这种流化效应。应通过旋转粘膜测定法进一步评估优化超塑剂的流体效应。最后，为了深入了解相互作用的超塑料水泥粘土，它将通过压力过滤研究，无论聚合物是否优先在水泥上还是在钙化的粘土上。