Doctoral (PhD) full time position ‘Durability of MFS-slag concrete’ in the framework of a collaborative project (DUSC) with industry


By incorporation of MFS-slag in concrete mixtures at high cement and/or aggregate replacement levels, the DUSC project strives for (i) maximum residue valorisation and avoidance of waste disposal, and (ii) more durable and sustainable reinforced concrete structures, with a low carbon footprint, high service life and good recyclability. MFS-slag based concrete (‘MFS-concrete’) is targeted which can be used as ready-mix concrete for structural applications, such as beams, columns and slabs of buildings and infrastructure. The study focusses on demonstrating equivalent performance of the MFS-concrete, compared to traditional concrete, in terms of workability, mechanical and durability behaviour. The project deals with two different cement replacement levels. At one hand, MFS-slag will be
used as supplementary cementitious material to replace at least 25% of OPC (Ordinary Portland Cement) in MFS-CS concrete. At the other hand, MFS-slag will be used at high (70%) OPC replacement levels by the additional use of an activator (or accelerator) in MFS-CA concrete. In addition to the replacement of the cement, both types also apply coarse aggregate replacement.

Clarification on the name MFS-slag:
The modified iron-silicate (MFS) slag as studied in this project is a co-product of the secondary copper production. The main oxides present in the slag are iron oxide and silicon oxide (abbreviated respectively as ‘F’ and ‘S’ in cement chemistry), besides the minor oxides as aluminum oxide and calcium oxide. The MFS-slag used in this project is produced by the Metallo Group, who invested recently in an innovative plasma-based fuming installation, capable of
providing clean iron-silicate slag.

This PhD project is taking place in the framework of the DUSC project (partners Ghent University, Van Pelt, Metallo, Sika and Resourcefull) and is funded by SIM (Strategic Initiative Materials - Flanders). The position starts at 1/05/2018 at the earliest and 1/09/2018 at the latest and will last for 3 years.

Some further information on the DUSC project and the related SIM MaRes program is provided in appendix.

Skills and personal qualities:
Applicants should have a master’s degree (or equivalent) in Civil or Structural Engineering, Civil Engineering Technology or related studies, with a strong interest in concrete technology, durability and sustainability assessment and modelling. Applicants which are in their final master year, and which will have obtained their master’s degree before 1/08/2018, can apply as well. Above all, applicants should have a high interest in scientific research; an independent and wellorganized working style, demanding high quality of your own work; well-developed social skills directed towards working in an interdisciplinary team, excellent interpersonal and communicative skills; strong motivation to succeed in scientific research, excellent presentation and scientific writing skills, excellent English language skills (verbally and written).

Applications must contain the following documents in Dutch or English: a personal (motivation) letter and curriculum vitae, a copy of degree certificates and associated certificates, a transcript of records of the bachelor and master curriculum, a copy of degree projects and any previous publications, and a proof of English language skills.
The documents should be sent to before the end of March 2018: Professor Stijn Matthys, Department of Structural Engineering, Magnel Laboratory for Concrete

SIM MaRES project DUSC
The DUSC project scientifically substantiates the use of MFS-slag in concrete: (i) to investigate and adapt the most appropriate production process parameters, (ii) to determine cement/aggregate replacement levels, (iii) to develop compatible and efficient chemical admixtures and (iv) to evaluate and model the workability, mechanical, durability, sustainability and recyclability performance of MFS-concrete. The objectives as presented below will be achieved through intensive collaboration between all partners.

  • Objective 1: To develop insights in the compositional parameters of MFS-slag and modelling its variability in function of the plasma fuming process parameters. To retain the most favourable conditions for MFS-slag production to be used as cement/aggregate replacement. The quality and homogeneity will comply to the use in structural concrete, with equivalent mechanical and durability performance as traditional concrete.
  • Objective 2: To develop improved reactivity tests to screen the applicability of MFS-slag as supplementary binder material in concrete (with or without activator).
  • Objective 3: To maximize the use of MFS-slag as cement and aggregate replacement in concrete. For MFS-CS, minimum 25% cement and 50% coarse aggregate replacement is targeted. For MFS-CA, the target is to increase the cement replacement to 70%, combined with 25% aggregate replacement. The final replacement levels will be derived from equivalent concrete performance in terms of fresh and hardened concrete properties (both mechanical and durability), in reference to ready mix C35-RC-EE2/3/4 .
  • Objective 4: To increase the efficiency of chemical admixtures (air-entraining agents, accelerators,  superplasticizers) in MFS-concrete by adapting its formulations and investigating its impact on performance based MFS-concrete. The admixtures will be fully compatible with the MFS-slag, to guarantee equivalent workability, mechanical and durability performance with respect to traditional concretes.
  • Objective 5: To scientifically substantiate the durability and sustainability performance of MFSconcrete. Durability will be assessed by equivalent concrete performance testing and service life prediction. Sustainability will be evaluated by life-cycle assessment, including end-of-life related impacts.
  • Objective 6: To evaluate the recyclability of MFS-concrete. Recycled MFS-concrete aggregates are targeted which comply to conformity requirements in accordance to NBN EN 206 and NBN B15-001.
  • Objective 7: To demonstrate MFS-concrete in a large-scale testing setting, for further proof of principle.

The DUSC project is part of the SIM (Strategic Initiative Materials) program on ‘Materials from
Solid and Liquid Industrial Process Residues (MaRes)’. Amongst other, DUSC will run parallel
with the SIM MaRes project ASHCEM (Novel Cements & Building Materials from Incineration