Axial-flexural interaction diagram of RPC columns reinforced with steel fibres

This paper presents analytical modelling of the axial-flexural behaviour of Reactive Powder Concrete (RPC) columns reinforced with and without steel fibres of different types (industrial and waste) in individual and hybrid forms. An analytical stress-strain model for unconfined RPC was used for the analysis of the axial loads and bending moments of the fibrous RPC columns. The layer-by-layer numerical integration method was used to calculate the axial load and bending moments in this study. The analytically developed axial load-bending moment ( P-M ) interaction diagrams were validated by using experimental results from the literature. A para- metric study was carried out to investigate the influence of the properties of steel fibres on the axial-flexural behaviour of fibrous RPC columns. It was found that the analytical unconfined stress-strain model used in this study well estimates the maximum axial loads and the maximum bending moments of the RPC columns re- inforced with and without different types of steel fibres. Also, the influence of the properties of steel fibres is more pronounced at eccentric and flexural loadin

Influence of Steel Fibres on the Behaviour of RPC Circular Columns Under Different Loading Conditions

An experimental program was conducted to investigate the effect of inclusion of steel fibres on the behaviour of Reactive Powder Concrete (RPC) columns. Three different types of steel fibre were used: micro straight steel fibre (MF), macro deformed steel fibre (DF) and waste steel fibre (WF) recovered from discarded tyres. In addition, a hybridization of steel fibres was made up to produce waste-industrial hybridization (WHF) (MF, DF and WF). Twenty reinforced RPC column specimens were prepared and tested under axial concentric, eccentric and flexural loading. Results of testing demonstrated that the ultimate axial load and the corresponding axial deformation increased effectively by the addition of steel fibres, especially at the presence of MF. For the flexural loading, the inclusion of WF and WHF increased the energy absorption of specimens by 470% and 453%, respectively, in comparison with the corresponding reference specimens. Axial load-bending moment (P-M) interaction diagrams were carried out. Results of testing show that WF is a promising material for enhancing the behaviour of RPC under different loading conditions

Mechanical properties of reactive powder concrete containing industrial and waste steel fibres at different ratios under compression

This paper investigates experimentally the influence of type, content and geometry of steel fibre (industrial/waste) on the mechanical properties of reactive powder concrete (RPC) in terms of compressive strength, tensile strength, modulus of elasticity and stress-strain behaviour under compression. Three types of steel fibres were used: industrial micro steel fibre (MF), industrial deformed steel fibre (DF) and waste steel fibre recovered from discarded tyres (WF). Steel fibres were added to RPC at 1%, 2%, 3% and 4% of the total volume. Two forms of steel fibres\u27 hybridizations were explored: industrial hybridization (HF) and waste-industrial hybridization (WHF). Results of testing demonstrate that the addition of DF and WF up to 3% and 4%, respectively, significantly affected the flowability of RPC. The addition of 4% MF achieved the highest increase in the compressive strength, tensile strength, modulus of elasticity, peak stress and the corresponding strain. The inclusion of HF increased the RPC toughness by 245%. Moreover, the inclusion of the waste steel fibre as full replacement (WF) or partial replacement (WHF) was comparable to the industrial steel fibre in enhancing the mechanical properties of RPC in addition to the increase in the toughness of RPC by 158.8% and 211%, respectively. Finally, WF is considered as a promising material in the structural applications and can fully or partially replace industrial steel fibres in RPC

Behaviour of fibre-reinforced RPC columns under different loading conditions

This paper investigates experimentally the influence of steel fibres inclusion on the behaviour of Reactive Powder Concrete (RPC) columns. Micro steel fibre (MF) and deformed steel fibres (DF) were used. Steel fibres were hybridized to produce hybrid steel fibre (HF). Sixteen RPC specimens were cast and tested under axial loading, eccentric loading (25 mm and 50 mm) and four-point bending. Results of testing demonstrated that RPC specimens that included MF exhibited 8-58% higher load carrying capacity compared to the reference NF specimens. Moreover, RPC specimens that included HF showed 29-408% higher ductility under different loading conditions compared to the reference specimens (NF). Also, the RPC specimens containing steel fibres exhibited 2-32% higher axial deformation under different loading conditions compared to NF specimens. Finally, it was observed that the RPC specimens reinforced with HF showed delayed spalling of concrete cover more than the RPC specimens that included MF and DF

Axial strength of fibrous reactive powder concrete circular columns

In this paper, a formula is proposed to calculate the nominal axial strength (Po) of fibrous reactive powder concrete (RPC) columns reinforced with steel fibres of different geometries and volume contents. The formula takes into account the effects of concrete, longitudinal reinforcement, transverse constraints, geometry of steel fibres and their volume content. A comparison is made with existing formulations that consider only for concrete and steel reinforcement. The proposed formula has been verified and validated by the experimental results of different types of steel fibre reinforced concrete (SFRC) columns in the literature. The results show that the current formulation considering only concrete and reinforcement significantly underestimatesPo of fibrous RPC columns. Furthermore, it is found that the proposed formula well predicts the nominal axial strength for fibrous RPC columns with an accuracy of 97–99%

Reactive powder concrete reinforced with steel fibre under different loading conditons

The focus of this thesis is to investigate experimentally and analytically the influence of type, content and geometry of steel fibre (industrial/waste) on the behaviour of unconfined and confined Reactive Powder Concrete (RPC) under loading. The influence of different types of steel fibre of different geometry and volume content on the mechanical properties of Reactive Powder Concrete (RPC) in terms of compressive strength, tensile strength, modulus of elasticity and stress-strain behaviour under compression was investigated. Also, the behaviour of the RPC columns that included different types of steel fibre of different geometry and volume content under different loading conditions was investigated. Furthermore, the feasibility of applying the existing empirical models on the unconfined and confined Reactive Powder Concrete (RPC) reinforced with different types of steel fiber under compression was assessed. Three types of steel fibres were used: industrial micro steel fibre (MF), industrial deformed steel fibre (DF) and waste steel fibre recovered from discarded tyres (WF). Steel fibres were added to RPC at 1%, 2%, 3% and 4% of the total volume. Two forms of hybridizations were explored: industrial hybridization (HF) and waste-industrial hybridization (WHF). The nonfibrous RPC specimens (reference) were labelled as (NF). The RPC specimens were cast and tested under compression for the behaviour of unconfined RPC. Also, twentyfour RPC columns were cast and tested under axial loading, eccentric loading (25 mm and 50 mm) and four-point bending

Influence of the Waste Steel Fibre Inclusion on the Mechanical Properties of Reactive Powder Concrete

The mechanical properties of Reactive Powder Concrete (RPC) containing waste steel fibre (WF) recovered from waste tyres were experimentally investigated. The WF was added to RPC mixture in ratios of 1%, 2%, 3% and 4% of the total volume. The conventional casting and curing methods were utilized. Results of testing demonstrate that increases in the compressive strength, tensile strength and modulus of elasticity were achieved. The addition of WF effectively improved the energy absorption capacity of the RPC. Furthermore, the WF increased the strain at the peak stress, which indicates an increase in the deformability resistance of the RPC. The post peak branch of the stress-strain curve were more flattened as the WF content increased, which indicates an improvement in the toughness of RPC. However, the addition of WF to RPC up to 3% was flowable while increasing the WF content up to 4% results in less workable concrete. Based on the results, WF is considered as a promising alternative for the industrial steel fibres in the structural applications

Stress–Strain Behavior of Helically Confined RPC Columns Reinforced with Steel Fibers under Concentric Loading

In this paper, an analytical stress–strain model is proposed that emphasizes the influence of steel fibers of different geometry and volume content on the behavior of the confined reactive powder concrete (RPC) columns. The proposed model takes into account the influence of the geometry and volume content of steel fiber on the behavior of the confined RPC column in terms of peak load, corresponding deformation, and post peak behavior. The behavior of the confined RPC columns reinforced with different types of steel fiber subjected to concentric loading is represented analytically. The analytical behavior of the fibrous RPC columns is verified with the results obtained experimentally from the literature. The outcomes show that the proposed analytical model to present the behavior of confined fibrous RPC columns is in very good agreement with the results obtained experimentally

Stress-Strain Relationship of Unconfined RPC Reinforced with Steel Fibers under Compression

In this paper, the feasibility of applying the existing empirical models on reactive powder concrete (RPC) reinforced with different types of steel fiber under compression was assessed. The behavior of RPC reinforced with different types of steel fibers of different geometry and volume content was highlighted. The outcomes show that the existing models overestimate the strain at peak stress, modulus of elasticity, and the ascending and descending branches of the stress-strain curve. Also, the influence of different types of steel fibers of different geometry and volume content has not been properly presented in the existing models. As such, an empirical model to predict the complete stress-strain curve of RPC reinforced with different types of steel fibers of different geometry and volume content of strengths ranging from 95 to 130 MPa is proposed. The results obtained from the proposed model were verified with the experimental results of RPC obtained in the literature. The proposed empirical model has been found to be in very good agreement with the stress-strain curves that were obtained experimentally