Behaviour of hybrid steel fibre reinforced self compacting concrete using innovative hooked-end steel fibres under tensile stress

Abstract

5 PO1 3AH, UK, +44 (0) 7415725441, clifford.okeh@port.ac.uk 6 7 ABSTRACT. 8The use of steel fibre hybridisation with different aspect ratios have been seen to enhance the pre and 9 post cracking response of concrete, however the invention of new innovative macro hooked ends steel 10 fibres with multiple hooks and increase in its linear length have been recently investigated. The results 11show that the new innovative macro hooked ends steel fibre with multiple hooks performed better than 12 single hooked ends steel fibre with respect to material properties when used in self-compacting 13 concrete. Therefore, the need to further investigate the performance of this new innovative macro 14 (MAC) hooked ends steel fibre when combined with straight micro (MIC) steel fibre of the same aspect 15 ratio in self-compacting concrete would be useful in the study of the stress-strain curve relationship of 16 this composite material. 17A laboratory investigation on two different conditions of steel fibre hybridisation using straight MIC 18 steel fibre (Length 13mm and diameter 0.2mm) with two different types of hooked ends MAC steel 19 fibres, Single (S1) and Double (M2) hook(s) at 0.75% and 1% fibre content respectively. These are 20 optimised values from previous experiments (laboratory tests conducted using different macro steel 21 fibres at 0.25%, 0.5%, 0.75% and 1% fibre content). The Uniaxial direct tension test method is used. 22The results show that steel fibre hybridisation decreased workability due to the influence of the micro 23 steel fibre content irrespective of the hooked ends steel fibre type. The use of Single hook (S1) macro 24 hooked end steel fibre in steel fibre hybridisation further improved the material properties (compressive 25 strength, tensile strength and fracture energy) when compared to the use of only macro hooked end steel 26 fibre. However a decrease in the fracture energy is observed when Double hooks M2 macro hooked end 27 steel fibre is used. Although positive results are seen with respect to other properties.28 29 Keywords: Single and double hooked ends steel fibres, Micro-steel fibre, Fracture energy, Tensile30 Strength, Compressive strength, Uniaxial tension test, Stress-strain relationship.31 32 33 34 35 Notwithstanding the improvement in the performance of SFRC with the inclusion of micro steel fibres 58 which affects the fibre matrix bond characteristics, the influence of macro steel fibre geometry (straight, 59 hooked, twisted, crimped etc.) presents different bond characteristics when used in concrete, hence 60 alters the behaviour in both the pre and post cracking zone (Lok and Pei 1998). 61The enhanced concrete performance in tension when single hooked end steel fibre is used compared to 62 straight steel fibre geometrical characteristics cannot be over-emphasised as a result of the additional 63 frictional force generated due to straightening of the hooks leading to higher frictional pull-out force 64 (Breitenbucher et al 2014) in addition to the improvement in the matrix adhesion...

Overview of trends in the application of waste materials in self-compacting concrete production

“…Also, numerous reports have shown that steel fibre possesses tensile properties suitable for improving the performance of SCC [13][14][15][16][17]. Particularly, the macro-hooked ends steel fibre with multiple hooks exhibited strong impact on strength of SCC as discussed in [18]. Most of the materials were found somewhat suitable in terms of mechanical characteristics of concrete; however, an optimum objective of SCC includes that it has an excellent fresh properties regardless of its composition.…”

Experimental and Analytical Study of Silica Particles on Self-Healing Concrete

“…From the rapid chloride permeability test (RCPT), the resistance to chloride ion penetration in the case of HM 3 is 32% higher than CC after 150 days. (6) The results show that it is suitable to use GGBS (with NSPs), RS, and CS to replace cement, river sand, and CAs in the concrete, respectively. HM 3 is considered the optimum mix for better performance, tends to fill the pores, and increases the mechanical strength of concrete.…”

“…In this project, the OPC 53 UltraTech brand is used. Tests according to IS 12269-2013 for cement are conducted and found suitable [6]. The chemical and physical characteristics of cement are placed in Tables 1 and 2.…”

Numerical Simulation of the Fracture Behavior of High-Performance Fiber-Reinforced Concrete by Using a Cohesive Crack-Based Inverse Analysis

“…Another possibility that has been recently explored is using combinations of fibres, the so-called fibre cocktails, in order to obtain high performance FRC with tailor made properties. Several authors have studied the mechanical properties of fibre cocktails of micro and macro steel fibres with outstanding results [ 15 , 16 , 17 ]. Fibre cocktails composed by polymer and steel fibres have been also studied, being already available in papers dealing with concrete formulations that combined polypropylene and steel fibres.…”