A comparative study on the use of mineral and chemical types of viscosity enhancers in self-compacting concrete

Title: A comparative study on the use of mineral and chemical types of viscosity enhancers in self-compacting concrete
Author(s): B. Felekoglu, M. Yucel Yardimci, B. Baradan
Paper category : conference
Book title: International RILEM Symposium on Self-Compacting Concrete
Editor(s): O. Wallevik and I. Nielsson
Print-ISBN: 2-912143-42-X
e-ISBN: 2912143713
Publisher: RILEM Publications SARL
Publication year: 2003
Pages: 446 - 456
Total Pages: 11
Nb references: 28
Language: English

Abstract: It is important to maintain adequate viscosity in order to obtain sufficient stability in self-compacting concrete. If the viscosity of concrete is too high, there is a risk of blocking when fresh concrete is forced to pass through narrow obstacles. On the other hand, if the viscosity is too low, the stability can not be maintained which leads to segregation and bleeding. Liquid components of concrete (water and superplasticizers) have a tendency to decrease the viscosity of fresh concrete at different magnitudes, so there is a need to use viscosity enhancers for highly fluid and stable concretes. There are two ways of increasing the viscosity of concrete; first to increase the powder content, second to incorporate a viscosity modifying chemical admixture. The aim of this paper is to present the results of an experimental study between self compacting concretes incorporating two types of powders (C-type fly ash, limestone powder) and semi synthetic cellulose-based chemical type of viscosity modifiers. Self-compactibility and compressive strength tests have been performed comparatively on both series. Test data indicated that powder type viscosity modifiers are more effective in both fresh and hardened state properties. The better performance of mineral powders in the fresh state, can be explained by relatively increased volume of paste which has an important role on the fluidity and stability properties. In the hardened state, the effectiveness of powders can be attributed to the increased solid phase of paste suspension resulting in a denser matrix structure. Also, the pozzolanic properties of fly ash contributed to the strength development of self-compacting concrete.

Online publication: 2003-08-21
Publication type : abstract_only
Public price (Euros): 0.00