Influence of Mixing Procedure on Robustness of Self-Consolidating Concrete

Ghent University, obtained from Research Foundation Flanders (FWO)

Department of Civil, Architectural and Environmental Engineering, Missouri S&T

Dimitri Feys
Assistant Professor
Missouri University of Science and Technology
128, Butler-Carlton Hall – 1401 N. Pine Street
Rolla, MO 65409
(573) 341-7193
feysd@mst.edu

2 graduate students
1 undergraduate researcher

Self-Consolidating Concrete is, in the fresh state, more sensitive to small variations in the constituent elements and the mixing procedure compared to Conventional Vibrated Concrete. Several studies have been performed recently to identify robustness of SCC and to develop solutions to increase the robustness of SCC. Ghent University obtained a major research project from the Research Foundation in Flanders (FWO) to investigate fundamentally robustness of SCC and to identify potential solutions in the form of alternative materials to enhance
robustness.

In the proposed research project, Missouri S&T intends to extend the research at Ghent University by investigating the influence of the mixing procedure on the robustness of SCC. The project is split into four tasks. In a first task, the sequence of adding the constituent elements and
mixing will be investigated by measuring the rheological properties of the produced mortars. In a second task, the consequences of the main influences of the mixing procedure will be compared to the influence of small variations of the most important constituent elements. In the third task, the results obtained on mortars are validated on concrete scale, while in the fourth task, the robustness of thixotropy and loss of workability will be investigated on concrete scale.

The research team hopes in this way to acquire more knowledge on the influence of the mixing procedure on the robustness of SCC, enabling the establishment of a set of guidelines. As a result, the practical application and perception of SCC in the construction and transportation industry can be enhanced.

Relationship to other Research/Projects

This is a stand-alone project.

Transportation-Related Keywords

Technology Transfer Activities

As a part of the technology transfer activities, the P.I. at Ghent University, Dr. De Schutter will spend some time with Dr. Feys at the Missouri University of Science and Technology to collaborate with the research team. Furthermore, workshops with students and industry will be prepared in the U.S.
The Ph.D. student working on this project at Ghent University will spend two months at Missouri S&T to collaborate with Dr. Feys and his team.
With the obtained results, two joint journal and two conference papers and presentations are anticipated, including a presentation and or poster at the annual NUTC Conference. The project will also be described
in a presentation for NUTC Webinars and in an article for the NUTC Newsletter.

Project Deliverables

The specific deliverables of this project are fourfold:

1. Identification of the most influencing mixing procedure parameters on the robustness of the rheological properties of Self-Consolidating Mortars
2. Investigation of the interaction of concrete mix design and mixing procedure on the robustness of Self-Consolidating Mortars
3. Validation of the obtained findings on Self-Consolidating Concrete scale
4. Research on the robustness of thixotropy and loss of workability of SCC by means of small variations in mix design

Overall, this project will enable the research team to better understand the influence of mixing procedure on robustness of SCC and to formulate guidelines for the optimization of the mixing procedure to minimize robustness problems in practice.

Furthermore, this project contributes to the larger project on robustness of SCC at Ghent University, enhancing the fundamental understanding of different phenomena influencing the robustness of SCC.

Anticipated Benefits

The results of this project allow the identification of the major influences
of the mixing procedure on the robustness of SCC. Increasing the robustness of SCC allows for a more precise design of SCC properties and less variations between different batches. This will enhance the practical applicability of SCC in the construction industry, whether in the precast or
the ready-mix industry. Controlling robustness of SCC enhances the quality during construction and repair of our infrastructure, improving construction procedures, avoiding problems on-site and reducing interference of less qualified workers. This will result in less durability problems and a longer service life which will on its turn reduce costs for repair, rehabilitation and postpone the replacement of the infrastructure.

The collaboration between Ghent University and the Missouri University of Science and Technology will enhance future communication and collaboration on other projects. Improved information exchange will increase the implementation of research findings from the other institute in practice. As a result, US Transportation Departments can benefit more extensively from results obtained abroad.

Milestones