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- Title
- SORPTIVITY, RESISTIVITY AND POROSITY OF CONCRETE CONTAINING SUPPLEMENTARY CEMENTITIOUS MATERIALS.
- Creator
- Barman, Sanjoy, Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Supplementary cementitious materials (SCMs), are beneficial when used as partial replacement of cement in concrete mixtures for coastal concrete structures, blended with Portland cement (binary or ternary mixes), i.e., high-performance concrete provides improved properties when exposed to marine harsh environment. In order to characterize selected durability properties of different concrete mixtures, a testing program was established. The intent of this study consists of testing 10cm diameter...
Show moreSupplementary cementitious materials (SCMs), are beneficial when used as partial replacement of cement in concrete mixtures for coastal concrete structures, blended with Portland cement (binary or ternary mixes), i.e., high-performance concrete provides improved properties when exposed to marine harsh environment. In order to characterize selected durability properties of different concrete mixtures, a testing program was established. The intent of this study consists of testing 10cm diameter x 20cm long concrete specimens prepared with a range of different mix designs. 1) to evaluate the rate of water absorption due to capillary suction, referred to as sorptivity, 2) to evaluate the concrete surface resistivity, 3) to evaluate and compare the total porosity of specimens with different mixes, and 4) to obtain correlations between resistivity and sorptivity. All of these experimental tests were carried out according to ASTM International Standards (Sorptivity, Porosity) and Florida Method of Test (Resistivity). The tests were performed on concrete samples at various ages. Moreover, The results provided a fast and reasonable approximation of the concrete durability over time. Ordinary portland cement was partially replaced with supplementary cementitious materials including: fly ash (20%), silica fume (8%) and blast furnace slag (50%). These SCMs are highly effective in creating more durable concrete design mixtures. The water-to-cementitious (w/cm) ratios of 0.41 and 0.35 were investigated. The concrete that contains pozzolanic materials has demonstrated progress in extending the time for initiation of corrosion. The test results obtained indicate that the concurrent inclusion of fly ash and silica fume greatly reduced water penetration. The mixes containing slag also showed lower porosity and water absorption result, when compared to specimens containing fly ash only. Ternary concrete mixtures specimens showed much higher surface resistivity values than binary mixture specimens. These results suggest that reducing w/cm ratio, adding SCMs to concrete mixtures improved the concrete durability. The possibilities for the risks of corrosion initiation would be minimized (delayed) by prescriptive and then performance-based concrete blends with SCM materials optimized for service exposure in aggressive environments.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013633
- Subject Headings
- Fly ash, High performance concrete, Porosity, Silica fume, Slag
- Format
- Document (PDF)
- Title
- Three-dimensional geomodeling to identify spatial relations between lithostratigraphy and porosity in the karst carbonate biscayne aquifer, southeastern Florida.
- Creator
- Westcott, Richard, Root, Tara L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
In southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology,...
Show moreIn southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology, cyclostratigraphy and porosity were created in a portion of the Biscayne aquifer. The models were built using published data from borehole geophysical measurements, core samples, and thin sections. Spatial relations between lithology, cyclostratigraphy, porosity, and preferential flow zones were compared and contrasted to better understand how these geologic features were inter-related. The models show local areas of differing porosity within and cross-cutting different cycles and lithologies. Porosity in the Biscayne aquifer study area follows a hierarchy attributed to lithofacies with a pattern of increasing porosity for the high frequency cycles. This modeling improves understanding of the distribution and interconnectedness of preferential flow zones, and is thus an invaluable tool for future studies of groundwater flow and groundwater contamination in the Biscayne aquifer.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004337, http://purl.flvc.org/fau/fd/FA00004337
- Subject Headings
- Biscayne Aquifer (Fla.), Geophysics -- Florida -- Miami Dade County, Groundwater flow -- Florida -- Miami Dade County -- Mathematical models, Hydrology, Karst -- Florida -- Miami Dade County, Porosity, Sedimentary basins -- Florida -- Biscayne Aquifer, Sedimentology -- Statistical methods, Soil permeability
- Format
- Document (PDF)
