FIBER INFLUENCE ON THE CLUTCH OF ARMATURES WITH CONCRETE

Abstract

Fiber concrete is one of the newest building materials, which is increasingly used in building practice. It is used in prefabricated and monolithic structures, working on sign-loaded loads. However, its properties are not fully disclosed and require more study for use in construction. One of the areas of use of this material is its joint work with core profile fittings, namely, clutch and anchoring. The purpose of the research is to use the fibers for better joint operation of the bar reinforcement with concrete. For the evaluation of the adhesion of steel reinforcement with reinforced concrete samples, the method of pulling out the reinforcement of the concrete specimen of the prismatic or cylindrical form is selected. Prisms of a square section measuring 150 x 150 mm and a length of 210 mm with steel bars fitted in them. The length of the anchoring in the samples was 10, 15 and 20 d. Plots that were not included in the work were separated in plastic tubes. The research was carried out with the use of the Ø8 mm class A500С steel fittings and steel wire fiber in the form of a straight section of the wire with a nominal length of 54 mm with anchors at the ends in the form of cones with a percentage of reinforcement of 2% of the total volume, as for concrete constructions with a high load. Experimental samples are made from concrete of the class В25 with a fraction of a large filler of 5-20 mm. Rose-plating is carried out not less than 3 days after concrete. For the control of the strength of concrete for compression (concrete class), samples of cubes measuring 150x150x150 mm are made. Test samples were taken at the age of 28 days. The number of prisms for samples with fibers was 9 pcs. with an anchorage height of 10, 15, 20d and similar for samples without fibers - 9 pcs. The analysis of the anchoring tests of the rod fittings in concrete and fiber reinforced concrete shows that until now the problem of gripping rod barriers in concrete reinforced with fiber has not been studied in Ukraine. The above results of the experimental studies of the connection of the Ø8 A500 rod reinforcement with concrete 32,11MPa concrete reinforced with anchor fiber of Ukrainian manufacture with a diameter of 0.5 mm and a length of 50 mm, using 60 kg / m3, showed that the reinforcing steel reinforced with steel fibers showed better performance clutch.