| dc.description.abstract | Pervious concrete has been widely used in parking lots and airport fields. However, past experience has shown durability and strength of the pervious concrete remains a challenge for adopting them in wider applications, as the binding material proportion is low and the use of fine aggregates is nearly zero. The position, size and shape distribution of voids in the pervious concrete microstructure control the overall behavior of the material. In this research, the influence of the distribution of voids on the strength, stiffness, and permeability of pervious concrete microstructure is studied by 2D image analysis and finite element modeling through MATLAB and ANSYS Parametric Design Language (APDL). The effect of the sample size of 2D microstructures is studied by varying the section size and a possible representative volume element (RVE) is therefore found. Predicted stress-strain plots are generated for the 2D specimen under compressive load and the obtained results, including stiffness, strength and permeability are compared with the results from the experiments conducted following ASTM standards.
In order to enhance bonding between reinforcement fiber and cement matrix, chemical treatment is adopted and applied on short polypropylene fibers when used in pervious concrete as reinforcement. The change in fiber surface due to the treatment is determined through fiber wettability test and Atomic Force Microscopy (AFM). Single fiber pullout tests are conducted to study the effect of the treatment type on fiber-cement interface properties. Treated fibers are then put into pervious concrete matrix for compressive and flexural strength tests.
With the chemical treated fibers, 2D microstructures of fiber reinforced pervious concrete are generated and cohesive zone technique is used to model the interface between fiber and concrete matrix, with its interface properties extracted from single fiber pullout tests. Load-displacement plots are generated in ANSYS for specimen under compression for different mixes. Through the validated micromechanical model and its modeling results of different fiber reinforced pervious concrete mix, an optimization method is developed to provide a useful tool for mix design of reinforced pervious concrete with chemically treated fibers. | en_US |
