2.2.1 Dovetailed cross section fibre (DT) The fibres tested herein are different in size and material composition; three fibres are tested; one of which makes use of a dove tailed (DT) fibre shape where the stretching and diameter change produces a gripping effect in the fibre dovetails and this permits greater stress transfer once the initial bond is broken. These fibres are referenced DT (Dovetail fibres). This DT fibre technology is compared against two different synthetic structural Type 2 fibres. The variables of the Type 2 fibres were, length, profile, polymer type and cross sectional area. Due to the complex shape of the fibres, the nominal diameters of the fibres are stated, not taking into account the undulations or dovetail features, both of which can provide additional load transfer beyond the first sign of fibre slippage when under load. The pulltruded polypropylene DT fibres were 2.0mm diameter and 60mm in length and manufactured from polypropylene having a modulus of elasticity of 3500 N/mm2. This fibre has the same material properties as Type B fibres used within this research. The design makes use of the contraction of the fibre material to enhance the fibre to cement paste mechanical bond when a tensile load is applied. The gripping effect is shown in Figure 1 when the polypropylene fibre is under load, and the black arrows indicate a gripping effect due to the Poisson effect. This was measured in Richardson et al [2]. Figure 1 - Cross sectional area of DT fibre under load. (Source [21]) Figure 2 shows the end detail of the DT fibre at x 100 magnification. The dovetail fibre features are clearly visible within Figure 2 and as the inset design detail by Thomas et al [21]. The DT fibres can be used as a direct replacement for other synthetic fibre types in concrete. Figure 2 - DT fibre 2mm diameter (Inset source [21]) – 2.2.2 Comparative fibre details (Types A and B). Two different structural types were used in conjunction with the DT fibres to compare against the DT fibres, as well as to compare the relative performance between themselves. The indented/crimped fibres (A) are 50 mm x 0.941 mm nominal diameter polyethylene Type 2 fibres that have a melting temperature of 164 °C and an elastic modulus of
2.2.1 Dovetailed cross section fibre (DT) The fibres tested herein are different in size and material composition; three fibres are tested; one of which makes use of a dove tailed (DT) fibre shape where the stretching and diameter change produces a gripping effect in the fibre dovetails and this permits greater stress transfer once the initial bond is broken. These fibres are referenced DT (Dovetail fibres). This DT fibre technology is compared against two different synthetic structural Type 2 fibres. The variables of the Type 2 fibres were, length, profile, polymer type and cross sectional area. Due to the complex shape of the fibres, the nominal diameters of the fibres are stated, not taking into account the undulations or dovetail features, both of which can provide additional load transfer beyond the first sign of fibre slippage when under load. The pulltruded polypropylene DT fibres were 2.0mm diameter and 60mm in length and manufactured from polypropylene having a modulus of elasticity of 3500 N/mm2. This fibre has the same material properties as Type B fibres used within this research. The design makes use of the contraction of the fibre material to enhance the fibre to cement paste mechanical bond when a tensile load is applied. The gripping effect is shown in Figure 1 when the polypropylene fibre is under load, and the black arrows indicate a gripping effect due to the Poisson effect. This was measured in Richardson et al [2]. Figure 1 - Cross sectional area of DT fibre under load. (Source [21]) Figure 2 shows the end detail of the DT fibre at x 100 magnification. The dovetail fibre features are clearly visible within Figure 2 and as the inset design detail by Thomas et al [21]. The DT fibres can be used as a direct replacement for other synthetic fibre types in concrete. Figure 2 - DT fibre 2mm diameter (Inset source – [21]) 2.2.2 Comparative fibre details (Types A and B). Two different structural types were used in conjunction with the DT fibres to compare against the DT fibres, as well as to compare the relative performance between themselves. The indented/crimped fibres (A) are 50 mm x 0.941 mm nominal diameter polyethylene Type 2 fibres that have a melting temperature of 164 °C and an elastic modulus of
Research_methodology_and_results_2.docx