Experimental Study On Basic Mechanical Properties Of Basalt Fiber Glazed Hollow Bead Concrete

Glazed hollow bead concrete can realize self-insulation of structure,effectively reduce building energy consumption,and improve the disadvantages of ordinary concrete,such as self-weight and poor toughness.However,due to the hollow and fragile physical characteristics of vitrified beads,it will bring negative effects on the strength of concrete.Basalt fiber has the characteristics of green environmental protection and large elastic modulus.The fiber mixed into glazed hollow bead concrete can improve the tensile and flexural properties of concrete and make it have better crack control ability.Fly ash and silica fume are mixed into glazed hollow bead concrete instead of cement,which can reduce the amount of cement and improve the strength of concrete.All three materials have a positive effect on the strength of concrete,and also echo the theme of environmental protection and energy saving of vitrified beads.Therefore,in this paper,different contents of basalt fiber,ultrafine fly ash and silica fume are added into glazed hollow bead concrete.The mechanical properties of basalt fiber glazed microbeads concrete beams under the optimal combination of factors are studied in order to obtain the failure mechanism,advantages and disadvantages of basalt fiber glazed microbeads concrete beams.The main research contents and achievements of this paper are as follows:(1)Under the condition that the volume and dosage of glazed hollow beads are the same,orthogonal test is designed to study the influence of different mixtures of ultrafine fly ash(10%、15%、20%),silica ash(4%、7%、10%)and basalt fiber(0.1%、0.2%、0.3%)on the basic mechanical properties of glazed hollow beads concrete,Range variance analysis was performed on the test results.The optimal level combination of factors is 15% superfine fly ash replacement,7% silica ash replacement and 0.2% basalt fiber content.(2)After determining the optimal horizontal combination of test factors,the cube compressive strength and thermal conductivity of basalt fiber vitreated microbead concrete were tested.The cube compressive strength and thermal conductivity were measured to be 43.7MPa and 0.88W/(m·k).It is concluded that basalt fiber glazed hollow bead concrete meets the strength requirements and has good thermal insulation performance.(3)According to the optimal horizontal combination of factors,the basalt fiber glazed hollow bead concrete beams were prepared,and the bending performance was tested,and compared with ordinary concrete beams and glazed microbead concrete beams.The results show that the failure patterns of the three test beams are similar.The vitreated microbead can improve the overall deformation capacity of the beam body and prevent the occurrence of penetrating cracks,but reduce the bearing capacity of the beam body.The addition of ultrafine fly ash,silica ash and basalt fiber can effectively improve the bearing capacity of vitreated microbead concrete beams,making them slightly higher than ordinary concrete.The cracking resistance of the beam body is further improved.(4)On the basis of the calculation formula of the bending bearing capacity and maximum crack width of fiber concrete beam,the coefficient of glazed hollow bead concrete was added to calculate the bearing capacity and maximum crack width of basalt fiber glazed hollow bead concrete beam.The measured value and the calculated value basically match,and the beam has a better safety guarantee according to the formula.