Influence of PCE-superplasticizer on the nucleation and growth of products obtained during the hydration of portland cement and the intercalation of polymers in C-S-H phases.

在混凝土和砂浆生产中，聚羧酸系聚合物(高效减水剂)的使用降低了水灰比，从而改善了工作性并增加了强度。作为一个缺点，这些高效减水剂与水泥化合物的相互作用阻碍了强度的发展。该应用的目的是研究水泥水化延迟的原因以及某种聚合物结构将液化与无延迟相结合的可能性。从纯熟料相C3S的溶解和结构不同的高效减水剂对水泥水化相纯结晶的影响来看，水泥水化应通过体系的改性来加速。因此，聚合物诱导的加速是可以获得的。除了致力于聚合物对水泥水化影响的动力学研究外，C-S-H相中聚合物的插层是本项目第三部分的主要内容。为了研究这种插层是否会同时改善水泥石的力学(主要是抗拉强度)和应变(主要是蠕变)性能。这项应用将继续为期一年的Fonded项目(LU 1652/1-2)，该项目旨在将水化部分分离为受高效减水剂影响的溶解和结晶。重点研究了反应动力学。在第一次实验中，证明了所用方法的适用性，这些方法可以用于溶出和结晶实验，不同有机添加剂的影响会延长溶出过程。主要水化产物为硅酸钙-水合物(C-S-H)相、硅灰石和钙矾石。在这些研究中，研究了高效减水剂结构(侧链长度、官能团数量等)的影响。对结晶速率的影响进行了研究。第三，研究了有机聚合物作为起始相插入C-S-H相晶面对水泥强度的影响。通过采用生物矿化原理，有望提高材料的性能。本课题是水泥研究的一个新领域，将对该领域的研究产生重大影响。此外，对水化机理和新材料性能的基本原理的详细了解也是材料科学(地质学、仿生学)的跨学科讨论的目标。

In concrete and mortar production the use of polycarboxylate based polymers (superplasticizer) leads to improved workability and increased strenght due to reduced water/cement ratios. As a drawback the strength development is retarded caused by the interaction of these superplasticizer with cement compounds. The application is aimed to investigate the causes of this retardation of the cement hydration and the possibility for a certain polymer architecture combining the liquefaction with no retardation. Based on the results obtained from the dissolution of the pure clinker phase C3S and from the pure crystallization of cementitious hydrous phases influenced by superplasticizer different in their structure, the cement hydration should be accelerated by modification of the system. Thus a polymer induced acceleration is obtainable. Besides kinetic studies dedicated to the hydration of cements influenced by polymers the intercalation of polymers in C-S-H phases is main topic in the 3rd part of the project. It is to investigate if such intercalation will improve both mechanic (mainly tensile strength) and strain (mainly creeping) properties of the cement stone.The application will continue the one year fonded project (LU 1652/1-2) which is aimed to separate the hydration parts into dissolution and crystallization both influenced by superplasticizers. Special attention is paid on the reaction kinetics. During the first fonding the suitability of used methods was proved and these methods can be used for the dissolution and crystallization experiments.The dissolution process will be extended by the influence of different organic additives. Homogeneous crystallization experiments will be performed on calcium-silicate-hydrate (C-S-H) phases, portlandite as well as ettringite as main hydration products. In these investigations the influence of the superplasticizer structure (side chain length, amount of functional groups, etc.) on the crystallization rate is investigated. The third point is the intercalation of organic polymers into the crystal planes of C-S-H phases as origin phase causing the strength in cement is investigated. By adaption of principles of biomineralization an increased performance of the material is expected. This topic is a new field for the research on cements and will lead to a significant effort in the field. Furthermore detailed knowledge of basic principles of the hydration mechanisms and new materials properties are aimed for interdisciplinary discussion on materials sciences (geology, bionic).