Optimization design of functionally graded ultra-high performance cementitious composite on flexural behavior

The research aims to investigate and optimize the flexural behavior of functionally graded ultra-high performance cementitious composite (FGUHPCC), and to optimize the design of FGUHPCC by using a numerical simulation program named RFPA(3D). The equivalent flexural strength and corresponding deflection capacity of double- and single-layered FGUHPCC beams were analyzed by carrying out four-point bending test. Furthermore, with the numerical model set in RFPA(3D), the crack evolution and acoustic emission (AE) event of specimens at limit of proportionality (LOP) point, modulus of rupture (MOR) point, and 30% of MOR are, therefore, discussed. The results indicate that functionally graded design can help to improve the flexural capacity and fracture toughness of all specimens. In addition, the main crack of FGUHPCC looks more irregular and larger damage areas are formed. Higher principal stress and more AE events can be identified in FGUHPCC than that of single-layer UHPCC. Based on the recorded test data, the influence of bottom layer thickness was also investigated with respect to the peak flexural load and the AE energy. The results indicate that the optimum load capacity and flexural energy can be obtained when layer thickness ratio is about 0.6.

Automated summary

This research aims to investigate and optimize the flexural behavior of functionally graded ultra-high performance cementitious composite (FGUHPCC) and optimize its design using numerical simulation. The results indicate that the functionally graded design can improve the flexural capacity and fracture toughness of the material.