Low Content Of Steel - Polypropylene Fiber Reinforced Concrete Flexural Toughness And Test Methods For Study

Fiber-hybrid is good to improve the toughness of cement reinforced concrete, and it has now aroused general attention both at home and abroad. In China, however, the study on flexural toughness of smaller volume steel fiber- polypropylene hybrid reinforced concrete is few at the moment. The current way to assess flexure of fiber- reinforced concrete still has some problems to be solved. Therefore, it's difficult to know its advantages on the toughness, which affects its application in programs. The paper did researches on the following aspects.1. Base on analysizing the effect on concrete strength and its workable performance by steel fiber and polypropylene hybrid fiber, chose to well-furnish smaller volume steel fiber- polypropylene hybrid reinforced concrete which can meet the requirement of construction technology, and is of middle and low grade.2. With the use of small testing machine, conduct the research on experimental methods for flexural toughness of fiber concrete. In apply with samples with gaps and short beams , analyzed the effect on stress field at the bottom of gap and damage by three gaps of different sharps through ANSYS, and it showed that compared with the result of CECS13: 89, the load- deflection curve of samples with gaps and short beams is obviously round, of experimental data is smaller, and mixmum number of samples in confidence interval is also much lower.3. Perfom the research on methods of evaluation on flexural toughness of fiber concrete. On the basis of references to German DBV and curve, when measured D₂^f, placed 3.15mm with 2.65mm forδ₂; Defined and worked out D₃^f. In order to make equivalent load more practical , analysized C₁,C₂,C₃ in the computational formula for equivalent load with respectively taking 0.5,5.0,10.0.Finally avoided negative values in the computing result ofζ_m,n,m of carrying capacity in the CECS13: 89.4. Make analysis on the flexural performance of smaller volume steel fiber- polypropylene hybrid reinforced concrete, when the strength was intensified, flexural toughness became stronger, but rising rate tended to low down. The flexural toughness of smaller volume steel fiber- polypropylene hybrid reinforced concrete became stronger as fiber content become larger, and form of relationship between flexural toughness and fiber content has also been found out.