Doctor of Philosophy (PhD)
Civil and Environmental Engineering
With respect to the problems caused by impervious pavements, cementitous permeable pavement (CPP) functions as a passive unit operation and process for stormwater quality and quantity control through infiltration, evaporation, filtration, absorption and reaction mechanisms. CPP pore characteristics were examined through pore connectivity analysis using X-Ray Tomography (XRT). Image resolution influence on image analysis results was evaluated. Relationships between parameters of pore characteristics were evaluated. Factors that significantly influence fluid flow in CPP media include effective porosity, pore connectivity and pore size distribution. A modified Kozeny-Carman model in which effective porosity, specific surface area based on effective pores (SSA)pe, and weighted tortuosity (Le/L)w were employed was developed and demonstrated applicable for CPP hydraulic conductivity estimation. Both the k-total porosity relationship and k-effective porosity relationship were developed with a power law model. Filtration of CPP subject to different particle loadings for a constant particle size gradation was investigated experimentally. Removal efficiencies for both total particles and for each size fraction were examined. A power law model was developed for the relationship between suspended solid concentration (SSC) and turbidity. CPP clogging potential was evaluated by measuring the temporal hydraulic conductivity, k(t) as well as the particles strained on CPP surface. Two CPP cleaning methods, vacuuming and sonicating followed by backwashing, were evaluated and found capable of recovering k0 up to 96%. A method for scheduling of CPP maintainance was presented. 3 groups of CPP specimens were sued to evaluate the capability of pH and alkalinity elevation and phosphorus removal functions of CPP. The removal efficiencies of total phosphorus (TP), total dissolved phosphorus (TDP) and total particulate phosphorus (TPP) were evaluated through experimental measurements. Factors that influence CPP strength and porosity, including water to cement ratio (w/c), aggregate to cement ratio (a/c), aggregate gradation and the degree of compaction, were evaluated through 6 mix designs with different design parameters. Based on test results, an optimized mix design was recommended, and a CPP structural with fc¡¯ > 25 MPa (3500 psi), fs > 2.76 MPa (400 psi), total porosity > 20%, and permeability k > 0.3 cm/s is desirable.
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Kuang, Xuheng, "Cementitious Permeable Pavement as a Passive Unit Operation and Process for Stormwater Quality and Quantity Control" (2005). LSU Doctoral Dissertations. 2325.