Since 2006, research funded by the Texas Department of Transportation (TxDOT) has evaluated the use of coatings and sealers for mitigating expansion due to alkali-silica reaction (ASR) and/or delayed ettringite formation (DEF) in hardened concrete. The report herein includes a project summary of previous work in Phase I, led by Racheal Lute (2008) and Charles Rust (2009). The Phase II research, described in this thesis, established concrete exposure blocks and NCHRP 244 Series II testing as the cornerstones of characterizing coating effectiveness. The studies assessed coating system performance by examining the contribution of steel reinforcement, the effects of aggregate reactivity, the size limitations of treatments, and the impact of painted concrete substrates. Lastly, this thesis describes the preliminary results of a field study site of columns supporting a flyover, and a concrete exposure block site in Houston, Texas. Overall, the results are encouraging as several coatings have reduced expansion by lowering internal relative humidity.

Chemical flooding has been studied for 50 years. However, never have the conditions encouraging its growth been as good as right now. Those conditions being new, improved technology and oil prices high enough to make implementation economical. The objective of this work was to develop economical, robust chemical formulations and processes that recover oil in field pilots when properly implemented. This experimental study goes through the process of testing surfactants to achieve optimal phase behavior, coreflooding with the best chemical formulations, improving the formulation and testing it in more corefloods, and then finally recommending the formulation to be tested in a field pilot. The target reservoir contains a light (34° API, 10 cP), non-reactive oil at about 22° C. The formation is a moderate permeability (50 - 300 mD) sandstone with a high clay content (up to 13%). Different surfactants and surfactant mixtures were tested with the oil including alkyl benzene sulfonates (ABS), Guerbet alcohol sulfates (GAS), alkyl propoxy sulfates, and internal olefin sulfonates (IOS). The best formulation contained 0.75% TDA -13PO-SO₄, 0.25% C₂₀₋₂₄ IOS, 0.75% isobutanol (IBA), 1% Na₂CO₃, all which are mixed in a softened fresh water from a supply well. Corefloods recovered 93% of residual oil from reservoir cores. Core flood experiments were also done with the alkali sodium carbonate to measure the effluent pH in a Bentheimer sandstone core with a cation exchange capacity (CEC) of 2 meq/100g. Floods at frontal velocities of 100, 10, and 0.33 ft/D were performed with 0.3 pore volume slugs of 0.7% Na₂CO₃ at 86° C. The effluent was analyzed for ions and pH breakthrough. It was found that the pH breakthrough occurred before surfactant breakthrough would be expected as desired although the pH was lower at a frontal velocity of 0.33 ft/D than at the higher velocities. The Na₂CO₃ consumption was 0.244, 0.238, and 0.207 meq/100 g rock at velocities of 100, 10, and 0.33 ft/D, respectively. In addition, a no-alkaline formulation consisting of a new large hydrophobe ether carboxylate surfactant mixed with an internal olefin sulfonate was tested on an active oil and it successfully recovered 99% of the waterflood remaining oil from an Ottawa sand pack with no salinity gradient and no alkali. The final residual oil saturation after the chemical flood (S[subscript orc]) was only 0.005 / text

Alkali-silica reaction (ASR) and delayed ettringite formation (DEF) deterioration have been a problem for the concrete infrastructure in the state of Texas and around the world in recent decades. A great deal of research into the causes and mechanisms of the deterioration has helped to prevent the formation of ASR and DEF in new construction, but the evaluation and maintenance of existing structures remains a problem. The goal of this research is to investigate the use of several nondestructive testing (NDT) methods to evaluate the level of ASR and DEF deterioration in a structural element. Based on the results, recommendations are made as to which NDT methods have the most potential to be incorporated into the evaluation process. / text

Reclamation of four salt-affected soils collected from southern Arizona was studied in the greenhouse and laboratory. Two rates of four amendments (sulphuric acid, gypsum, ammonium polysulphide, and ammonium thiosulphate) were applied in triplicate. Results were evaluated in terms of changes in nutrient availability, ions removed by leaching, plant growth, and infiltration rates. In most cases the high rates of sulphuric acid and gypsum increased the solubility of the major cations (Na, K, Ca, and Mg) in the soil. If the required amount of leaching water were applied to the soil, a significant amount of these cations, especially Na, was leached from the soil. For the Gothard soil (saline-sodic) two pore volumes were sufficient to accomplish leaching, but were insuffcient for the Guest (nonsaline-slightly sodic) and Gilman (highly saline-sodic) soils. High rates of sulphuric acid and gypsum decreased the pH and increased the EC for all soils, although the EC was not significant at the 5% level for the Mohall (nonsaline-nonsodic, calcareous) soil. All treatments decreased the pH of the Gothard soil significantly; however, the greatest increase in EC and least pH were obtained from acid application. Regarding changes in phosphorus (P), all treatments increased the amount of soluble P in the leachates from the Gothard and Guest soils; whereas available soil P increased significantly only with the acid treatments. None of the treatments affected the amount of P in the Gilman soil leachates, but acid and gypsum increased the available soil P. Ammonium polysulphide and ammonium thiosulphate tended to increase available P but the increase was not significant at the 5% level. None of the treatments affected the P parameters for the Mohall soil. Sulphuric acid increased growth and P uptake of alfalfa plants on all soils except the Mohall. Gypsum and ammonium polysulphide increased P uptake on the Gothard and Guest soils whereas ammonium thiosulphate increased P uptake only for the Guest soil. Sulphuric acid and gypsum increased the infiltration rates for all four soils. Thiosulphate produced intermediate infiltration rates while the lowest rates were found with ammonium polysulphide and the untreated soils. Although amendment rates were based on equivalent amounts of sulphur and their effectiveness in supplying soluble calcium, and the exchangeable sodium status of each soil, results varied according to such factors as rate of oxidation of the amendment, lime content of the soil, soluble salts present in the soil, and soil texture.

This study consisted of laboratory and greenhouse experiments designed to determine the effect of sulfur waste materials on acidulation and other properties of calcareous soils. The laboratory experiment was conducted in the Soils, Water and Engineering Department, University of Arizona, for a period of nine weeks. Laveen soil (containing 6% CaCO₃) was treated with two levels of Morocco rock phosphate (0, 500 ppm P), and two different waste materials of sulfur, Cake S and Foam S, each with three levels (0, 5000, 10000 ppm). Treated soils were incubated for two periods (three and nine weeks) at 27°C and 66% water holding capacity. The design of the experiment was a complete randomized block with 24 treatments and two replications. Data were evaluated by analysis of variance and multiple means comparison tests for soil pH, soluble phosphorus, and sulfate, and regression analysis for the isotherm. Results showed that Foam sulfur had a greater effect as compared with Cake sulfur on soil pH, soluble phosphorus and sulfate and significantly shifted the isotherm to the right. Rock phosphate had no effect on soil pH and sulfate, but tended to decrease soluble phosphorus and shifted the isotherm to the left as compared with the control. The second experiment was conducted in the greenhouse near the Agricultural Sciences Building, University of Arizona, for a period of 32 weeks starting on August 20, 1979. Two calcareous soils, Pima and Laveen, (2% and 6% CaCO₃, respectively) were investigated with three levels of rock phosphate (0, 250, 500 ppm P), and three sources of sulfur (Cake, Foam and pure sulfur) each at two levels (0, 8000 ppm S). Two levels of super phosphate were used as a standard treatment. The chemical treatments were mixed with the soil and transferred to plastic pots and moistened to 70% water holding capacity, then covered with plastic sheets and incubated for eight weeks. Following the incubation, tomatoes were planted and grown for a six week period. Dry weights were measured only in the Pima soil but were eliminated due to poor stand in the Laveen soil. Barley was planted after the tomato harvest. Tomato and barley plants were irrigated with distilled water until the first harvest, after which barley was irrigated with tap water and CaSO₄ saturated to eliminate sulfur deficiency detected prior to the first harvest. The experiment was a complete randomized block design with 36 treatments and three replications. Data for soils and plants were evaluated by analysis of variance, multiple means comparison test, and regression analysis. From the results of this study the conclusions were as follows: (1) Foam sulfur tended to increase soluble P and Zn, lowered soil pH, and shifted the P isotherm to the right in the soil. Plant P and dry weight were increased more by the Foam S than Cake S and pure sulfur. However, Foam S tended to increase soluble salts more than Cake S and pure S. (2) Cake S also caused an increase in soluble P in the soil, reduced soil pH, and increased plant P and dry weight as well, although the effects were less than with Foam S. (3) Rock phosphate plus sulfur resulted in an increase in soluble P after 32 weeks of application. (4) Soils with low CaCO₃ content, higher organic matter content, and higher cation exchange capacity favored increased oxidation of sulfur to sulfate resulting in increased soluble P and lower soil pH. (5) Linear regression analysis of the P sorption isotherm was carried out by plotting the P remaining in the solution (ppm) on the X-axis versis P sorbed by the soil (ppm); a linear power function resulted. By this relationship, any regression equation can be used to evaluate the P status of a soil and the statistical differences between treatments.

No description available.

Studying chemical enhanced oil recovery (EOR) in a high-temperature/high-salinity (HT/HS) reservoir will help expand the application of chemical EOR to more challenging environments. Until recently, chemical EOR was not recommended at reservoirs that contain high concentrations of divalent cations without the need to recondition the reservoir by flooding it with less saline/ less hardness brines. This strategy was found ineffective in preparing the reservoir for chemical flooding. Surfactants used for chemical flooding operating in high temperatures tend to precipitate when exposed to high concentrations of divalent cations and will partition to the oil phase at high salinities. In this study amphoteric surfactant was used to replace the traditionally used anionic surfactants. Amphoteric surfactants show higher multivalent cations tolerance with better thermal stability. A modified amphoteric surfactant with lower adsorption properties was evaluated for oil recovery. Organic alkali was used to eliminate the water softening process when preparing the chemical solution and reduce potential scale problems caused by precipitation due to incompatibility between chemical slug containing alkali and formation brine. Using organic alkali helped in minimizing softening required when preparing an alkali-surfactant-polymer (ASP) solution using seawater. Solution prepared with organic alkali showed the least injectivity decline when compared to traditional alkalis (NaOH and Na2CO3) and sodium metaborate. Adding organic alkali helped further reduce IFT values when added to surfactant solution. Amphoteric surfactant was found to produce low IFT values at low concentrations and can operate at high salinity / high hardness conditions. When mixed with polymer it improved the viscosity of the surfactant-polymer (SP) solution when prepared in high salinity mixing water (6% NaCl). When prepared in seawater and tested in reservoir temperature (95°C) no reduction in viscosity was found. Unlike the anionic surfactant that causes reduction in viscosity of the SP solution at reservoir temperature. This will not require increasing the polymer concentration in the chemical slug. Unlike the case when anionic surfactant was used and more polymer need to be added to compensate the reduction in viscosity. Berea sandstone cores show lower recovery compared to dolomite cores. It was also found that Berea cores were more sensitive to polymer concentration and type and injectivity decline can be a serious issue during chemical and polymer injection. Dolomite did not show injectivity decline during chemical and polymer flooding and was not sensitive to the polymer concentration when a polymer with low molecular weight was used. CT scan was employed to study the displacement of oil during ASP, SP, polymer and surfactant flooding. The formation and propagation oil bank was observed during these core flood experiments. ASP and SP flooding showed the highest recovery, and formation and propagation of oil bank was clearer in these experiments compared to surfactant flooding. It was found that in Berea sandstone with a permeability range of 50 to 80 md that the recovery and fluid flow was through some dominating and some smaller channels. This explained the deviation from piston-like displacement, where a sharp change in saturation in part of the flood related to the dominated channels and tapered front with late arrival when oil is recovered from the smaller channels. It was concluded that the recovery in the case of sandstone was dominated by the fluid flow and chemical propagation in the porous media not by the effectiveness of the chemical slug to lower the IFT between the displacing fluid and oil.

Fly Ash was tested in relation to its ability to mitigate alkali-silica reaction, its contribution to strength, electrical resistance and heat release with the aim of recommending improvements to fly ash specifications. ASTM C 1567 accelerated mortar bar test results were in agreement with an expansion limit of 0.10 % at 14 days. A non-standard alkali leaching test showed that with high alkali fly ashes as replacement level increases the amount of alkalis leached increases while prism expansions decrease. Measures of pozzolanic activity can be improved by measuring against non-pozzolanic fillers, This requires high replacement levels to reduce statistical variability. Isothermal calorimetry tests showed that high calcium fly ashes can lead to delays in hydration, these delays can be reduced by calcium hydroxide additions. Calcium sulphate additions can also improve hydration.

An investigation on the damaging effects of potassium acetate deicer (KAc) on concrete durability was conducted. Different SCM replacement levels were used. ASTM C 1293 and ASTM C 1260 test methods results indicated that KAc is capable of inducing alkali-silica reaction (ASR) expansion in specimens containing reactive aggregate. Class C fly ash was ineffective even at a replacement level of 45%. Class F fly ash and slag were effective in mitigating ASR expansion for specimens exposed to diluted (25% by weight) KAc. KAc showed an increase in pH value upon exposure to concrete specimens. Concrete specimen without SCM and exposed to deicers had higher [K]/[Na] molar ratio near the surface but ions penetrated less compared to specimens containing SCM. ASTM C 666 and MTO LS-412 test methods results showed that air-entrained concrete slabs and prisms without SCM and exposed to KAc are resistant to scaling and freezing and thawing damage.

Fly Ash was tested in relation to its ability to mitigate alkali-silica reaction, its contribution to strength, electrical resistance and heat release with the aim of recommending improvements to fly ash specifications. ASTM C 1567 accelerated mortar bar test results were in agreement with an expansion limit of 0.10 % at 14 days. A non-standard alkali leaching test showed that with high alkali fly ashes as replacement level increases the amount of alkalis leached increases while prism expansions decrease. Measures of pozzolanic activity can be improved by measuring against non-pozzolanic fillers, This requires high replacement levels to reduce statistical variability. Isothermal calorimetry tests showed that high calcium fly ashes can lead to delays in hydration, these delays can be reduced by calcium hydroxide additions. Calcium sulphate additions can also improve hydration.