The construction of a road extension of Park Avenue through the Pennsylvania State University’s agricultural fields offered an opportunity to reinvestigate, in more detail, the Tudek jasper quarry site (36CE238). The original investigation was led by Dr. James Hatch and graduate students from the University’s Department of Anthropology. Initial studies yielded in excess of 27,000 artifacts that were used in this analysis. Our reinvestigation resulted in the construction of a detailed outline of the quarry site and the pattern of usage of the materials from the site. Additionally, radiocarbon dating indicated that the site was intensively utilized for a long period of time (3500 BC to 1500 AD) and confirmed that, like many quarry sites, the activities included primary materials collection and testing, reduction of the lithic materials for transport to another location where the final finishing of tools took place. Moreover, the availability of raw material likely changed through time and across the quarry. Observed color changes in the jasper suggest some heat treatment on site, primarily during later time periods.

Pennsylvania is a leader in utilizing coal wastes such as anthracite culm and bituminous coal gob in fluidized bed combustion (FBC) boilers. Alkaline FBC fly ash could contain large proportions of calcium and sulfur bearing minerals. Although FBC ashes typically do not meet ASTM C618 due to high SO3 and loss on ignition (LOI), they have the potential to be beneficially used in filling and reclamation of mine land features. However, leaching of harmful elements from ash deposits and consequent groundwater contamination is an environmental concern. This study assessed the leaching behavior of Schuylkill FBC ash monofills exposed to neutral water flow in a column scale. The assessment included characterizing the coal ash (via scanning electron microscopy and X-ray diffraction), and flow-through leaching test in a 30cm column. In comparison with pulverized coal ash, the studied FBC ash contained higher clay and quartz and lower glass content, with 8% LOI. Within 8 days, alkalinity of fly ash raised the pH from 5 to 11. Under neutral inflow condition, Si, Al, and Fe concentrations slowly decreased, while Mg content was almost constant. Calcium and Sulfur contents decreased by a factor of 2 and Na and K contents dropped by a factor of 3 to 5. Among trace elements, molybdenum, associated with S and Ca, decreased from 1.30 to 0.08 mg/L, while Se, and As contents (associated with clay particles) were almost constant during 8 days. It was found that all detected trace elements were below Pennsylvania maximum acceptable leaching limits.

The unburned carbon (UC) content of fly ash impacts the performance (e.g., air entrainment, rheology) of concrete mixtures. The loss on ignition (LOI) test is commonly used to estimate the UC content; however, this may be inaccurate, as the weight change upon igniting fly ash is also due to calcination of carbonates, desorption of bound water, and oxidation of sulfur and iron minerals. In this study, a two-atmosphere thermogravimetric analysis (2A-TGA) coupled with mass spectrometry (MS) was performed to evaluate the chemical reactions that occur upon heating of fly ash and to measure the true UC content. 2A-TGA was performed under two distinct atmospheres: (i) in non-oxidizing helium gas, to measure weight loss due to decomposition of carbonates and loss of bound water and (ii) in oxidizing air, to measure weight loss due to conversion of UC to carbon dioxide (CO2). The method was applied to five class F fly ashes with LOI in the range 1.89 % to 7.66 %, a class C fly ash (LOI = 3.86 %), and a fluidized bed combustion (FBC) ash (LOI = 8.10 %). The results were also compared with the total carbon (TC) of each fly ash measured using infrared (IR) spectroscopy via a commercial Laboratory Equipment Corporation (LECO) carbon analyzer. The results show that there is no one-to-one relationship between the LOI and the TC or UC contents of fly ash. LOI overestimated TC by up to 2.5 times and overestimated UC by up to 6.4 times.

Coal combustion products (CCPs) are by-products created when coal is burned for energy production. These products include predominantly fly ash, bottom ash, and flue gas desulfurization (FGD) by-products. These materials can be a viable alternative to natural resources for the construction of engineered fills. Because of the variability in the chemical composition, CCPs require mineralogical, chemical, and mechanical characterization to ensure its applicability as a construction material. Furthermore, CCP characterization should also address the material's changing properties with time. To date, only limited standards have been proposed to characterize these materials to determine the viability of their use as structural fill. The purpose of this study is to apply a minimal set of practical mechanical and chemical tests that will characterize and predict CCP time-based performance intended for large-volume civil engineering applications such as embankments and mine reclamation. Unconfined compressive strength tests, hydraulic conductivity measurements, and X-ray diffraction (XRD) analysis were performed at curing times from 1 to 180 days on three materials: fluidized bed combustion (FBC) ash, flue gas desulfurization (FGD) ash, and pulverized coal (PC) class F fly ash. Results show that the unconfined compressive strength varied between each of the materials and over time for both the FBC and PC fly ashes, whereas the strength of the FGD ash did not appear to change over time. The FBC ash experienced a significant strength gain with increased curing time. The XRD characterization shows that the strength gain in the FBC ash is likely caused by the formation of ettringite. The FBC ash also showed significant changes in hydraulic conductivity with curing time.

Unburned carbon in fly ash can significantly affect its beneficial applications in concrete mixtures. The water requirement and rheological properties of concrete are influenced as high carbon content ashes generally require greater water/binder ratio to show good workability. The dosage of air entraining agents (AEA) in concretes containing fly ash is also affected by carbon content. Loss on ignition (LOI) test is a generally accepted method for estimating the unburned carbon content of fly ash. However, it has been observed that LOI results may overestimate the amount of organic carbon as the ignition mass loss is not only due to burning of organic carbon, but also due to other possible reactions such as calcination of inorganic carbonates, desorption of physically and chemically bound water (e.g., dehydration of portlandite), and oxidation of sulfur and iron minerals. In this study, a modified thermogravimetric analysis (TGA) is performed under two distinct atmospheres; helium, a non-oxidizing atmosphere to measure ignition loss due to carbonates and bound water, and air as an oxidizing atmosphere to measure the true organic carbon content. This method is applied to a class F fly ash with low LOI. X-ray diffraction (XRD) and bulk chemical analysis were also used to better assess changes in composition and mineralogy of ashes during the ignition process. The two step TGA method could successfully separate carbon oxidation from other possible reactions recognized using mass spectrometry and thermal analyses techniques.

Deterioration was observed to occur in the wearing surfaces, decks, and parapets for all seven of the structures inspected. To date, little to no deck condition change was observed compared to the reviewed inspection reports. However, the oldest bridge in this study was noted to be carrying the highest volume of Gas Play truck traffic and manifested some structural deterioration that was not included in the most recent Pennsylvania Department of Transportation (PennDOT) inspection survey. This involved the bridge’s superstructure and substructure showing sagging bridge beams. For all other bridges, an increase in traffic as a result of the Gas Play was not shown to significantly change the condition of the superstructure or substructure in the bridges. Bridge 4 received extensive rehabilitation in 2009. After the one-year interval that followed, this study found deterioration to the wearing surface, parapets, and approach slab. All roadways had varying amounts of cracking regardless of Gas Play traffic activity, which generally increased with increased truck traffic. Rutting significantly increased as Gas Play activity increased and was the most common form of deterioration encountered. Secondary and municipal roads have experienced significant deterioration due to the enhanced heavy truck traffic. Full-depth reclamation is being employed as a cost-effective rehabilitation methodology by the gas companies. Reconstruction of dirt and gravel municipal roads has commonly been undertaken without the benefit of good design guidelines. To address this shortcoming, the authors developed and presented a simplified design methodology for the reconstruction of this class of roads. The enhanced heavy truck traffic has a weak correlation to increased severity of traffic accidents. Limited data and lack of a good baseline for comparison limit the strength of associated observations. Focus on the direct impact of drilling (e.g., archaeological survey) on cultural resources, while important, doesn’t address important down-the-line impacts. As roads are rebuilt and improved, historic and prehistoric survey is critical but there are not specific resources and staff available for these issues. Local heritage leaders are currently bearing the full weight of the new issues associated with Marcellus development. Creating resources for local and regional leaders is important, so that they can develop long-term planning strategies for cultural resource management and preservation.

Roman hydraulic maritime concretes of the central Italian coast have pumiceous volcanic ash, or pulvis Puteolanus, from the Bay of Naples as mortar pozzolan. Petrographic and mineralogical analyses of cement microstructures in relict lime, tuff, and pumice clasts suggest that pozzolanic reaction at high pH produced gel-like calcium-aluminum-silica-hydrate cements. Orthorhombic 11 Å-tobermorite, with unit cell dimensions a = 5.591(1)Å, b = 3.695(1)Å, c = 22.86(1)Å, developed in the residual cores of portlandite clasts and in certain pumiceous clasts, as well. Ettringite and calcium-chloroaluminate formed in discrete, perimetral microstructures and in the cementitious matrix. Phillipsite and chabazite cements may reflect later dissolution of alkali-rich volcanic glass at pH 9–10. The cement systems have remained stable for 2,000 years, during partial to full immersion in seawater. Vitruvius’ De architectura and other ancient texts describe the raw materials of the concretes, preparation of lime, and construction of submerged wooden forms. Information concerning the materials, formulations, and installations of the concretes was apparently spread by movement of central Italian engineers around the Mediterranean but also, perhaps, by the circulation of sub-literary engineering manuals. Further analytical investigations will determine the diverse chemical processes that produced the cement microstructures, and why the harbour constructions have endured for two millennia.

Coal combustion products (CCPs) are by-products created when coal is burned for energy production. These products include predominately fly ash, bottom ash, and flue gas desulfurization (FGD) by-products. In 2007 alone, the United States produced in excess of 125 million tons of CCPs. Of these 125 million tons, 60% of the material was deposited in landfills. Yet, these materials can be a viable alternative to natural resources for the construction of engineering structures. Due to the variability in the chemical composition, CCPs require proper characterization - mineralogical, chemical, and mechanical - to insure its applicability as a construction material. To date, only limited standards have been proposed to characterize CCPs to determine the viability of their use as structural fill. While these standards offer some performance insight, an organized, systematic approach for evaluating the engineering properties of CCPs does not yet exist. The development of a standard set of practical material characterization, mechanical, and chemical tests to qualify CCPs for large-volume applications would provide a sound engineering and environmental basis for greater use of these materials. The purpose of this study is to develop a standard testing framework for characterizing CCPs for use as construction materials in large-volume applications, such as embankments and mine reclamation. Material and mechanical characterization protocols are modified after standard soil (particulate materials) testing procedures, while chemical characterization focuses on both the solid phase of the material as well as analysis of dissolution products. Once the testing protocol was established, it was implemented for two specific types of CCPs in order to confirm the adequacy of the testing protocol. Testing was conducted over a period of 180 days to assess material property evolution with curing time.

High strength mortars have been prepared utilizing optimized particle packing, reactive substituents to modify the chemistry- and addition of superplasticizers. Otherwise the processing techniques were conventional. The compressive strengths of one prototype material after curing at temperatures from 38 C to 250 C were above 70 MPa. The strengths were particularly high at 175 C (195 MPa) where excellent bonding had developed; one chemically modified material reached 245 MPa. The specimens cured at 175 and 250 C (after a lower temperature precure) developed their strengths rapidly, having reached essentially full strength by 7 days. At lower curing temperatures the strength increased with time, apparently still increasing at 56 days (106 MPa) for the materials cured at 38 C. Modified mixtures were prepared using different proportions of silica fume, MgO, different ratios of sand to fine components, and different sand mineralogy and other admixture proportions for rheological optimization. Microhardness, dynamic Young’s modulus, density, and permeability were measured in addition to strength. Matrix chemistry and sand mineralogy and proportions affected the strength. Matrix-aggregate bond was very important. The above types of cementitious materials have potential importance for applications where they may be exposed to extreme conditions and to temperature cycling.

The highly durable pozzolanic mortars of wall concretes from the Theater of Marcellus and Great Hall of Trajan’s Markets preserve traces of micromorphological textures in altered Pozzolane Rosse volcanic ash. Reaction of hydrated lime with potassic scoriaeceous ash, and halloysite, phillipsite, and chabazite surface coatings, as well as Tufo Lionato tuff particles, produced distinct, alkaliand alumina-calcium-silica hydrate cement microstructures, including strätlingite. The assemblage of diverse pozzolanic components in the Trajanic mortar was remarkably effective in combining hydrated lime.

Preliminary geochemical evaluations of some portland cement based materials have been made in Nevada Nuclear Waste Storage Investigations (NNWSI), for possible nuclear waste repository sealing applications in welded tuff focused in the Yucca Mountain area. Portland cement based sealing materials have been evaluated in the NNWSI for possible sealing applications in a nuclear waste repository in the Topopah Spring tuff member. Cementitious sealing materials developed for long-term stability should be as nearly as possible in thermodynamic equilibrium with the host rock, or any disequilibrium should not have negative impact upon the integrity of the host rock. A primary step in achieving this equilibrium condition is to minimize the chemical potential between the sealant and the host rock. Two different approaches were evaluated to achieve this compatibility. The one approach utilized indigenous materials for the formulation of the concrete and the other utilized reactive admixtures to adjust the bulk chemical composition of the concrete formulation to approximate the local rock bulk chemistry. Testing of both formulations at conditions that represented the maximum credible temperature and pressure conditions of a repository were completed and show that the use of an indigenous tuff in the formulation without adjusting the matrix chemistry caused alterations which might compromise the performance of the concrete. In contrast, the chemically adjusted cementitious formulation exhibited minimal alteration in the J-13 groundwater of the designed test.

Because of the ever-increasing cost associated with asphalt repaving, interest has been growing in turning back deteriorating asphalt roadways into maintainable aggregate driving surfaces. For more than 10 years, Pennsylvania's Dirt and Gravel Road Maintenance Program has funded projects that use environmentally sensitive maintenance techniques to reduce sediment pollution on unpaved roads while providing low-cost, long-range road maintenance solutions. The Center for Dirt and Gravel Road Studies at Pennsylvania State University has worked with various state and local entities on projects designed to convert these deteriorated asphalt roadways into durable, maintainable gravel surfaces, with a focus on reducing the environmental concerns related to road runoff. The purpose of this paper is to provide a detailed accounting of one such project. Several accepted options are available to accomplish this task. For this project, the full-depth reclamation process that uses chemical stabilization techniques was selected as the methodology to be demonstrated. As the project progressed, several site-specific challenges were encountered and ultimately resulted in a change in the tactics employed to effect the conversion from asphalt to gravel successfully. The results of the study emphasize the importance of properly evaluating preconstruction site conditions to determine the best methodology to be employed and of providing for flexibility in the design criteria and specifications.

The compaction and fracture of brittle spherical particles in a cylindrical vessel were experimentally and numerically studied in the context of the American Petroleum Institute Recommended Practice 60 for proppants used in the hydraulic fracturing of oil and gas wells. Because pressures within the cylindrical vessel could not be directly measured, strain was experimentally determined via gauges along the outside surface. In addition, an epoxy resin was also injected at various loading stages to "freeze" the damage states for analysis. In addition, acoustic emissions were monitored in situ to determine damage signatures that could be correlated with the frozen test and strain measurement data. Experimental results were then compared to finite element simulations by using an assumed double-exponential pressure distribution applied to the inner face of the vessel. The results indicated that the assumed pressure distribution adequately described the loading state within the cylinder and revealed apparent stratification of damaged proppants near the top and bottom of the container. In addition, the damaged proppants and acoustic emission signatures showed that the damage increases progressively with the loading in distinct stages characterized by fracture and subsequent stress redistribution.

The stability of a tailored ceramic waste form under hydrothermal conditions was the subject of several previous papers [1,7–10] from this laboratory. One of the results reported in these studies was the apparent dissolution and reprecipitation of the alkaline-earth molybdate phases (scheelite-structure phase). The composition of the scheelite-structure phase after hydrothermal treatment was different from that before treatment (approximately Ca95Sr5 after and Ca35Sr40Ba25 before). A schematic phase diagram was presented at that time to explain the results obtained. This paper is a report of our attempt to experimentally determine the phase relations in the alkaline-earth molybdate (Ca, Sr, and Ba) and verify our previous interpretation. For this work, we prepared compositions throughout the ternary system and heated them at 1200°C for periods of 2 to 24 hours. The experimental products were characterized by x-ray diffraction and SEM/EDX examination. At 1200°C, the two-phase solvus is nearly symmetric and extends from near the pure calcium and barium end-members to about 35 mole percent strontium at the critical point of the solvus. The increase in grain size, uniformity of composition within and between grains of the same phase and the approach to “textural equilibrium” in the 1200°C experiments all strongly suggest that equilibrium was attained. New, calcium-rich compositions are suggested for the scheelite-structure phases in the supercalcine-ceramics based upon the interpretation of data from this study. This observation forces a re-examination of the assumption concerning the partitioning of Sr and Ba amongst the phases in the supercalcine-ceramic.

Candidate backfill materials such as montmorillonite and clinoptilolite with and without the presence of simulated nuclear waste solids such as borosilicate glass, glass ceramic, sintered ceramic and supercalcine ceramic were investigated under repository simulating conditions (=300°C and 30 MPa). Experiments were conducted under semi-wet as well as wet repository conditions. Montmorillonite and clinoptilolite did not seem to alter under both semi-wet and wet repository conditions as determined by XRD. However, the above backfill materials reacted extensively with wastes under both conditions. They altered to feldspar (oligoclase) in the presence of borosilicate glass and to analcime in the presence of particular ceramics under both semi-wet and wet repository conditions. Alteration of montmorillonite could not be detected either in the presence of the glass ceramic or supercalcine ceramic under both repository conditions. However, clinoptilolite altered to analcime in the presence of glass ceramic or supercalcine ceramic under wet repository conditions. Reactions of backfill materials with simulated wastes immobilized waste elements such as Cs, Mo, etc., by forming new phases such as analcime, oligoclase and powellite. In fact, analyses of product solutions from interaction runs indicated that the presence of backfill materials during the alteration of waste solids served to drastically reduce the concentration of some radionuclides in solutions. These results suggest that properly selected backfills can provide the simplest and most effective chemical (or thermodynamic) engineered barrier in an intelligently designed multibarrier system. Moreover, they indicate that the μ, P, and T in the usual leach tests (e.g. Paige, IAEA, etc.) are such that results of such tests cannot have any value in evaluating waste form behavior under repository conditions.