FINITE ELEMENT MODEL OF HIGH STRENGTH REDUCED MODULUS HIGH PERFORMANCE CONCRETE

摘要

High Performance Concrete (HPC) with early strength development is the material of choice in the fabrication of prestressed concrete railroad ties. The higher strength of HPC results in significantly higher values of the Elastic Modulus and increases the brittleness and the rigidity of the material, leading to premature cracking and the deterioration of the railroad ties. A High-Strength Reduced-Modulus High Performance Concrete (HSRM-HPC) material has been developed by the authors and used in the fabrication of prototype concrete ties. Detailed models based on the Finite Element Method of the HSRM-HPC have been developed to simulate the ASTM-C469 tests for elastic modulus. The HSRM-HPC constituent materials, i.e. aggregates and cement mortar, have been explicitly modeled and assigned properties determined experimentally. Aggregates size and distribution is modeled using a combination of probabilistic distributions consistent with the results of an experimental sieve analysis. Details of the development of each model are discussed. The models are verified with experimental data. Assessment studies have been performed in order to optimize the models with respect to efficiency, the quality of the results and computational times.