Experimental Study on Mechanical Properties of Basalt Fibre Reinforced Concrete
Concrete is very strong in compression but very weak in tension. However it is reported that tensile and bending strength of concrete is 10 to 15% of the compressive strength respectively. The addition of different types of fibres in concrete have significantly improves its compressive as well as tensile strength. Among the new advancement in field of FRC is the basalt fibre reinforced concrete. In the present study basalt chopped fibres were used in the concrete mixes and compressive and flexural strength of the specimens were tested. A total of 5 mixes were prepared by varying the percentages of basalt fibres on M 25 grade of concrete mix. Based on the laboratory results the compressive and flexural strength was reported to increase up to 46% and 74%. However the workability of fresh concrete mixes is not much affected by the addition of fibre content. The flexural strength of concrete is improved which shows the wide application of basalt fibres in concrete mixes for construction in various fields i.erailway, bridges, runway and tunnels.
Mechanical Performance of Basalt Fibre Reinforced Concretes
The fresh and hardened characteristics of concrete reinforced with basalt fiber (BF) have been investigated in the presented study. The chopped micro BF with the length of 12 mm are included in concrete mixes at 0.2%, 0.4%, 0.6% and 0.8% of total volume along with the variation of water to cement ratios (w/c) of 0.47 and 0.59. Mechanical features of concrete incorporating BF are specified using the parameters obtained from static modulus of elasticity, compressive, flexural and splitting tensile strength tests. The multi objective optimization analyses using response surface method (RSM) is performed by the parameterization of the minimized cost and the maximized performance based on the dependent parameters presented. Test results reveal that the mechanical properties are improved while the workability of concrete is remarkably deteriorated by BF incorporation. The optimization analysis has inferred that the BF content of 0.356% provides the optimum result with the w/c ratio of 0.47.
Sagging and Hogging Strengthening of Continuous Reinforced Concrete Beams Using CarbonFiber-Reinforced Polymer Sheets
The testing of 11 reinforced concrete 2-span beams strengthened in flexure with externally bonded carbon fiber-reinforced polymer (CFRP) sheets is reported. The beams were classified into 2 groups according to the arrangement of the internal steel reinforcement. Each group included 1 unstrengthened control beam. The main parameters studied were the position, length, and number of CFRP layers. External strengthening using CFRP sheets was found to increase the beam load capacity. All strengthened beams exhibited less ductility compared with the unstrengthened control beams, however, and showed undesirable sudden failure modes. There was an optimum number of CFRP layers beyond which there was no further enhancement in the beam capacity. Extending the CFRP sheet length to cover the entire hogging/sagging zones did not prevent peeling failure of the CFRP sheets, which was the dominant factor mode of beams tested.