Bonding Behaviour of Steel Fibres in UHPFRC Based on Alkali-Activated Slag

Abstract

The mechanical performance of fibre-reinforced ultra-high-performance concrete based on alkali-activated slag was investigated, concentrating on the use of steel fibres. The flexural strength is slightly higher compared to the UHPC based on Ordinary Portland Cement (OPC) as the binder. Correlating the flexural strength test with multiple fibre-pullout tests, an increase in the bonding behaviour at the interfacial-transition zone of the AAM-UHPC was found compared to the OPC-UHPC. Microstructural investigations on the fibres after storage in an artificial pore solution and a potassium waterglass indicated a dissolution of the metallic surface. This occurred more strongly with the potassium waterglass, which was used as an activator solution in the case of the AAM-UHPC. From this, it can be assumed that the stronger bond results from this initial etching for steel fibres in the AAM-UHPC compared to the OPC-UHPC. The difference in the bond strength of both fibre types, the brass-coated steel fibres and the stainless-steel fibres, was rather low for the AAM-UHPC compared to the OPC-UHPC.

Fibre reinforced ultra‐high performance concrete – Rheology, fibre bond strength and flexural strength

“…This work will connect and discuss the results of several investigations at the Department of Structural Materials and Construction Chemistry at the University of Kassel. These were carried out to get a better understanding of various aspects of fibre reinforced concrete [6][7][8][9][10][11][12][13][14][15]. This includes investigations regarding the bond behaviour of different fibre materials, fibre modifications and concrete mixtures as well as functionalization of the fibre reinforcement to improve concrete properties.…”

Ultra‐high performance alkali‐activated slag as a reusable mold for light metal casting

“…On the other hand, the rheological properties and water demand cannot be optimized by superplasticizers as in the case of Portland-cement based UHPC because conventional superplasticizers are unstable in the highly alkaline environment of AAMs. By using silica fume, the workability of AAM can be improved and low water/binder ratios can be achieved, resulting in high strength [7,12]. Since the compressive strength of these high-performance AAM is similar to that of UHPC, these materials can be referred to as AAM-UHPC.…”

Prediction Model Based on DoE and FTIR Data to Control Fast Setting and Early Shrinkage of Alkaline-Activated Slag/Silica Fume Blended Cementitious Material

“…To reduce shrinkage, additives like shrinkage reducers can be used, which, however, reduce the strength. In addition, additives have been shown to have a negative effect in GGBFS-based systems in most cases [29,39] and only have a limited effect in GGBFS/silica fume blended binders [40]. Those GGBFS/silica fume composites are characterized by a low w/b value, which can reduce drying shrinkage.…”