Performance evaluation for struclural applicalions of fiber reinforced mortar showing tensile resistance and fine cracks

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The properties of High Performance Fiber Reinforce Cement Composites (HPFRCC) showing fine cracks and tensile resistance were investigated to accelerate the applications.1. Material performance and evaluation methodsA portable tension testing apparatus for HPFRCC was proposed The remarkable effects of the specimen thickness on the cracking strength and tensile strength were not recognized. The smaller specimens showed the larger cracking strength, tensile strength and ultimate tensile strain. A method of direst tension testing on dumbbell specimens fabricated using beam pieces sawed from blocks was proposed. When an increase in the number of fanned and troweled surfaces, under which fibers tend to be oriented, the tensile strength and the ultimate strain increased. The tensile creep strain after formation of cracks increased with an increase in both the crack number and the crack width HPFRCC not only without cracks but also with multiple fine cracks had a good freeze-thaw resistance.2. Member performance and structural applicationsThe effects of the amount of steel reinforcement and the cover thickness on the crack number and width of reinforced HPFRCC beams were small. Wheel running tests in water on HPFRCC overlaid on a steel deck plate revealed that HPFRCC soon deteriorated due to the induced high water pressure inside fine cracks. To avoid the deterioration, it was pointed out to be important to reduce the water pressure in cracks and to make the structure watertight, where the water does not penetrate into the interface between HPFRCC and the steel deck plate by the sufficient draining The resifts of this study have been adopted in the recommendation (draft) for the design and construction of HPFACC, which was published by Japan Society of Civil Engineers.