Investigating the Rheological Behavior of Low Water-to-Cement Concretes Admixed With Superplasticizers and Co-Dispersants and the Underlying Dispersion Mechanism

研究掺有高效减水剂和助分散剂的低水灰比混凝土的流变行为及其分散机制

• 批准号: 387082770
• 负责人: Professor Dr. Johann Plank
• 金额: --
• 依托单位: Lehrstuhl für Bauchemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387082770?language=en
• 关键词: Investigating; Rheological; Behavior; Low; Water

Concretes formulated at very low w/c ratios (< 0.30) have become increasingly popular. However, applicators often report a honey-like consistency for those concretes which creep rather than flow and exhibit a low speed of flow when poured at the job site. Such rheological behavior is highly undesirable for the placement process.The aim of the project is to ascertain the main causes for the stickiness and creeping flow behavior of concretes of low w/c ratios and to provide potential solutions to overcome such unfavorable rheological properties. Regarding this, specific structural motifs for PCE superplasticizers will be identified which favor a high speed of flow. Additionally, non-ionic co-dispersants will be tested as flow enhancers and the working mechanism underlying this new type of dispersion will be investigated in more detail by using different experimental techniques (e.g. dynamic light scattering, critical micelle concentration etc.).The overall goal of this project is to significantly deepen the knowledge on the dispersion mechanisms occurring specifically in low w/c systems, and to interconnect the data obtained for the adsorbed layer thickness, HLB values and structural motifs of individual PCE molecules with key rheological parameters such as yield stress, plastic viscosity and flow speed.

以非常低的水灰比（< 0.30）配制的混凝土越来越受欢迎。然而，施工人员经常报告这些混凝土具有类似蜂蜜的稠度，这些混凝土会蠕变而不是流动，并且在施工现场浇注时表现出低流速。这种流变行为对于浇筑过程来说是非常不希望出现的。该项目的目的是确定低水灰比混凝土的粘性和蠕变流动行为的主要原因，并提供潜在的解决方案来克服这种不利的流变特性。就此而言，将确定 PCE 超增塑剂的特定结构基序，这些基序有利于高速流动。此外，非离子助分散剂将作为流动增强剂进行测试，并且将通过使用不同的实验技术（例如动态光散射、临界胶束浓度等）更详细地研究这种新型分散体的工作机制。该项目的目标是显着加深对低水灰比系统中特别发生的分散机制的了解，并将获得的吸附层厚度、HLB 值和单个 PCE 分子的结构图案数据与关键流变参数（例如屈服应力、塑性粘度和流动速度。