Polypropylene fibers are embedded to prevent reactive powder concrete （RPC） from spalling failure under high temperatures. This paper probes the influence of embedded fibers at various volumetric dosages on the ther...Polypropylene fibers are embedded to prevent reactive powder concrete （RPC） from spalling failure under high temperatures. This paper probes the influence of embedded fibers at various volumetric dosages on the thermomechanical properties of polypropylene-fibered reactive powder concrete （PPRPC） exposed to high tem- peratures up to 350 ℃ and on the spalling performance and characteristics up to 600 ℃. The thermomechanical prop- erties include the characteristic temperature for spalling, and residual strengths, such as the compressive strength, split tensile strength, and flexural tensile strength. A high- definition charge-coupled device camera and scanning electron microscope technology were employed to capture the spalling processes and to detect the microstructural changes in the materials with various fiber dosages. To understand and characterize the mechanism by which polypropylene fibers influence the thermal spalling of RPC, a numerical model to determine the moisture migration and vapor pressure transmission during spalling was developed in this paper. It showed that there was an optimal volu- metric dosage of fibers to prevent PPRPC from explosive spalling. The relationships between the mechanical char- acteristics of PPRPC and the fiber dosages were derived based on experimental data.展开更多
基金supported by the National Natural Science Foundation of China(51125017 and 50974125)Research Fund for Doctoral Programs of Chinese Ministry of Education(20110023110015)+1 种基金the Fund for Creative Research & Development Group Program of Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Polypropylene fibers are embedded to prevent reactive powder concrete （RPC） from spalling failure under high temperatures. This paper probes the influence of embedded fibers at various volumetric dosages on the thermomechanical properties of polypropylene-fibered reactive powder concrete （PPRPC） exposed to high tem- peratures up to 350 ℃ and on the spalling performance and characteristics up to 600 ℃. The thermomechanical prop- erties include the characteristic temperature for spalling, and residual strengths, such as the compressive strength, split tensile strength, and flexural tensile strength. A high- definition charge-coupled device camera and scanning electron microscope technology were employed to capture the spalling processes and to detect the microstructural changes in the materials with various fiber dosages. To understand and characterize the mechanism by which polypropylene fibers influence the thermal spalling of RPC, a numerical model to determine the moisture migration and vapor pressure transmission during spalling was developed in this paper. It showed that there was an optimal volu- metric dosage of fibers to prevent PPRPC from explosive spalling. The relationships between the mechanical char- acteristics of PPRPC and the fiber dosages were derived based on experimental data.
