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）配制的混凝土已经变得越来越受欢迎。然而，施涂者经常报告那些混凝土的蜂蜜状稠度，其蠕变而不是流动，并且当在工作现场浇注时表现出低速流动。这种流变行为是非常不可取的浇筑过程中。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，以克服这种不利的流变性能。关于这一点，PCE超增塑剂的特定结构基序将被确定为有利于高流速。此外，非离子共分散剂将作为流动增强剂进行测试，并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。该项目的总体目标是显着深化知识的分散机制，特别是发生在低w/c系统，并互连所获得的数据的吸附层厚度，HLB值和结构图案的个别PCE分子与关键流变参数，如屈服应力，塑性粘度和流速。