EXPERIMENTAL STUDIES OF SERIAL REINFORCED CONCRETE PAG SLAB WITH ADDITIONAL STEEL FIBER REINFORCEMENT

Abstract

Thus, in laboratory conditions, experimental studies of the bearing capacity and crack resistance of a serial PAG plate with additional steel fiber reinforcement in the amount of 1% were carried out. In accordance with the regulatory documents in force in Ukraine, one of two possible load schemes was considered ― when loaded by a concentrated force applied to the cantilever part of the slab. The plate was tested on a specially made stand consisting of four support racks connected in pairs by beams on which the plate rested. The load was applied across the width of the slab in steps of 0.04 from the destructive load, in two concentrated vertical strips. Each level of load ended with a five-minute exposure, at the beginning and end of which the readings on the measuring devices were taken. All tests were carried out using two 30-ton jacks and a 50-ton dynamometer. The working principle of the jack consisted in the fact that its lower plane pressed on a two-level cross-beam system, and through it the load was distributed on the slab. In the process of testing the plates, the applied load, deflections and deformations were recorded. Clock-type indicators and protractors were used as measuring devices. The process of crack formation on the plate surfaces was observed with the help of a Brinell tube in the places of the largest crack opening. 
 As a result of the tests, the bearing capacity of the plate was 211.2 kN with a bending moment of 101.4 kNm. The load corresponding to the beginning of crack formation is equal to 96.0 kN at a bending moment of 46.1 kNm. The maximum width of crack opening was 0.25 mm. According to the readings of the indicators, graphs of the dependence of the relative deformation on the load were constructed. Graphs of the dependence of deflections on the load, constructed from the data of two deflection gauges. Before the appearance of the first crack, the maximum deflection of the plate is 17.0% of the deflection recorded at the end of the tests.