Experimental and Computational Analysis of the Behavior of Ultra High Performance Concrete, Prestressed Concrete, and Waterless Martian Concrete at Early Age and Beyond

As more advanced concrete based infrastructure materials find their way into practice, also increasing is the demand of computational models capable of simulating and predicting their behavior at early age and beyond. In this work, a computational aging framework coupling a hygro-thermo-chemical (HTC) theory and a comprehensive mesoscale Lattice Discrete Particle Model (LDPM) is proposed. The proposed A-LDPM model is then utilized to simulate and predict various mechanical behaviors of Ultra High Performance Concrete at early age with calibrated mesoscale material parameters based on a comprehensive experimental campaign. Size effect studies are also carried out with experiments and A-LDPM modeling, which shows great capabilities of accurately capturing the age dependent size effect and fracture characteristics of UHPC. With the final goal of modeling structural scale responses, LDPM is utilized to simulate mechanical behavior of five meters long shear beams with full reinforcement and various prestress levels. The simulated results, failure types, major crack locations and magnitudes have high agreement with those of experiments. However a gap exists between the experimental and simulated stiffness of response due to not including creep and shrinkage effects. Thus, an extended A-LDPM framework is proposed to also take into account the coupled effects of creep, shrinkage and steel relaxation.;In addition to the increasing development of infrastructure materials, also demanded in the 21st century are advanced construction materials for space exploration. With the plan of human settlement on Mars in the near future, a sulfur-based high strength waterless Martian Concrete (MC) is developed by hot mixing sulfur and simulated Martian soil. The optimum composition is selected based on comprehensive experimental studies, by which the strengths of the material are determined. The results are compared with sulfur concrete with regular sand in furtherance of sieve analysis, microscope studies and X-ray photoelectron spectroscopy analysis. It is found that the optimum aggregate distribution facilitates the high strength of MC. Moreover, sulfates and polysulfides are formed in MC during hot mixing, which further enhances its strengths. The mechanical tests of the optimum MC are then simulated by LDPM with high accuracy.