Experimental Study On Mechanical Properties Of Steel-jute Hybrid Fiber Concrete

Based on the theory of composite materials,this paper combines steel and jute fiber materials with concrete substrate,and puts forward a kind of economical,environmental protection,excellent performance,and meet the engineering requirements of steel-jute hybrid fiber reinforced concrete(HFRC).The fiber in concrete makes full use of its own advantages,showing positive mixed effect in each stage,improving the mechanical properties of concrete.In this paper,through the analysis of mechanical properties test and fiber blending effect theory,the strengthening effect of steel and jute mixed fiber on concrete is explored,and the optimal dosage is obtained.The main work and conclusion of this paper include the following aspects:(1)Based on the orthogonal test of three factors and four levels,the range and variance analysis were carried out with the volume percentage of steel fiber,jute fiber and fly ash replacement rate as the test factors and the cubic compressive strength of hybrid fiber concrete as the evaluation index.The analysis results show that the three factors affecting the compressive strength of HFRC from strong to weak are successively: steel fiber volume percentage → jute fiber volume percentage → fly ash replacement rate.(2)The splitting tensile test of steel-jute HFRC was carried out.After range analysis and variance analysis of the test data,it was concluded that the splitting tensile strength of HFRC was affected by three factors in order from strong to weak: steel fiber volume percentage → jute fiber volume percentage → fly ash replacement rate.L15 group is the best combination of fiber content,the HFRC splitting tensile strength of this group is88.97% higher than plain concrete,and the volume percentage of steel fiber is 1.5%,the volume percentage of jute fiber is 1% and the replacement rate of fly ash is 10%.(3)The effects of three factors on the flexural strength of HFRC were studied through the three-point flexural test of 48 trabecular specimens.The results show that the influence of the three factors on the flexural strength is the same as that of the splitting tensile strength.The optimal mix of flexstrength is as follows: steel fiber volume percentage is 1.5%,jute fiber volume percentage is 1% and fly ash replacement rate is10%.At this time,the flexural strength is 7.27 MPa,39% higher than ordinary concrete.(4)Sixteen groups(3 in each group)of mixed fiber concrete round cake specimens were designed.The drop hammer impact test results show that the optimal impact strength of the fiber content combination is: steel fiber volume rate is 1.5%,jute fiber volume rate is 1% and fly ash replacement rate is 10%.Meanwhile,according to Weibull distribution theory,the probability statistics method was used to analyze the initial and final crack impact times of 16 groups of HFRC specimens.The fitting effect was good and there was a good correlation.(5)The internal microstructure of concrete was observed by SEM scanning electron microscope.The influence of different fibers on the concrete microstructure and the bridging effect of fibers are analyzed.The results show that the fiber is evenly distributed in the concrete matrix,and the fiber is closely bonded to the cement base,which improves the micro pore structure of concrete.Figure 39 Table 32 Reference 80...