Experiment and Analysis of Mechanical Properties of Lightweight Concrete Prefabricated Building Structure Beams

Abstract Recent years have witnessed that the prefabricated concrete structure is in the widespread use of building structures. This structure, however, still has some weaknesses, such as excessive weight of components, high requirements for construction equipment, difficult alignment of nodes, and poor installation accuracy. In order to handle the problems mentioned above, the prefabricated component made of lightweight concrete is adopted. At the same time, this prefabricated component is beneficial to reducing the load of the building structure itself and improving the safety and economy of the building structure. Nevertheless, it is rarely found that the researches and applications of lightweight concrete for stressed members are conducted. In this context, this paper replaces ordinary coarse aggregate with lightweight ceramsite or foam based on the C60 concrete mix ratio so as to obtain a mix ratio of C40 lightweight concrete that meets the engineering standards. Besides, ceramsite concrete beams and foamed concrete beams are fabricated. Moreover, through three-point bending tests, this paper further explores the mechanical properties of lightweight concrete beams and plain concrete beams during normal use conditions. As demonstrated in the results, the mechanical properties of the foamed concrete beam are similar to those of the plain concrete beam. Compared to plain concrete beams, the density of foamed concrete beams was lower by 23.4%; moreover, the ductility and toughness of foamed concrete were higher by 13% and 3%, respectively. However, in comparison with the plain concrete beam, the mechanical properties of the ceramsite concrete beam have some differences, with relatively large dispersion and obvious brittle failure characteristics. Moreover, in consideration of the nonlinear deformation characteristics of reinforced concrete beams, the theoretical calculation value of beam deflection was given in this paper based on the assumption of flat section and the principle of virtual work. The theoretically calculated deflection values of ordinary concrete beams and foamed concrete beams are in good agreement with the experimental values under normal use conditions, verifying the rationality and effectiveness of the calculation method. The research results of this paper can be taken as a reference for similar engineering designs.