Study On The Anisotropy Of 3D Printed Fibre Reinforced Ceramsite Concrete

The use of ceramsite prepared from river bottom mud for building materials can achieve greening and low cost of building materials.In recent years,building-grade 3D printing rapidly develops with its advantages of non-molding,fast speed,and automation.3D printing of building mainly adopts cement-based materials,adopts river sand as fine aggregate.The use of ceramsite for 3D printing concrete to replace river sand has great engineering application value based on the lack of river sand resources in China.Moreover,concrete is a brittle material and the safety of plain concrete printed structures is questioned.Therefore,this study proposes a method for preparing fiber ceramsite concrete using 3D printing technology.Firstly,the optimum amount of ceramsite is determined by physicochemical analysis and water absorption test.Secondly,the printability of five kinds of basalt fiber reinforced ceramsite concrete is evaluated by an extrusion printer,and the optimal ratio is obtained.Finally,the XY plane is used as the horizontal printing layer,and the Z direction is perpendicular to the center of the horizontal printing layer,that is,the three directions of X,Y,and Z are orthogonal to each other,and the X direction is an outer point perpendicular to the center of the cross section of the printed layer,and the Y direction is an outer point perpendicular to the center of the side of the printed layer,and the Z direction is the outer point perpendicular to the center of the flat section of the printed layer.The uniaxial compression test and the three-point bending test are performed on the printed test pieces from these three directions to study the the anisotropy of 3D printed fiber reinforced ceramsite concrete mechanics.At the same time,the anisotropy coefficient and its evaluation method are proposed by using concrete ultrasonic tester to characterize the anisotropy of materials.The results show that the 3D printed fiber reinforced ceramsite concrete has obvious mechanical anisotropy.When subjected to compressive load,the strength of the specimen in the X direction is the highest,and the strength of the specimen in the Y direction is the highest when subjected to bending loads.The addition of fiber has a great influence on the mechanical anisotropy.The larger the fiber content,the greater the difference in anisotropy.