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.
Highlights
The main characteristics of ultra-high-performance concrete are its low capillary porosity and its high compressive strength [1]
As reported in [6], the M1 mix was composed of slag and silica fumes as precursors, quartz sand and quartz powder were used as aggregates, and a mix of potassium waterglass and potassium hydroxide was used as the activator solution
The performance of M4 was comparable to M3; the difference in the mix design was a different type of silica fume (SF2), which was derived from ferro-silicium production
Summary
The main characteristics of ultra-high-performance concrete are its low capillary porosity and its high compressive strength [1]. Both characteristics evolve from its low water/binder ratio and its microstructure optimization by the use of reactive fines such as silica fumes. An issue with OPC-based ultra-high-performance concrete is the high content of cement. Due to the benefits of its high compressive strength, less concrete is needed and in terms of the CO2-, water-, and material-footprint, this type of concrete can be beneficial [2]. It was shown that due to the use of silica fumes in certain amounts, the rheological behaviour of the AAM-UHPC could be improved and a water/binder ratio even lower than 0.2 could be realized without using any superplasticizers. The use of superplasticizers in that high-alkaline system is rather inefficient [7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
