This study developed a procedure to identify concrete bridge decks that are exhibiting the charac... more This study developed a procedure to identify concrete bridge decks that are exhibiting the characteristics associated with falling concrete. Field exploratory work on reinforced concrete bridge decks was supported by analytical and laboratory investigations. The field work included visual inspection, non-destructive tests, and sampling of full-depth cores and powder samples from the bottom of the bridge deck. Chief variables assessed were the chance of corrosion by the half-cell potential, chloride content at the location of the bottom reinforcement, and the concrete pH level. The chloride diffusivity was estimated from the chloride profile. The laboratory investigation was performed on bridge deck beams. The beams were constructed from concrete containing chloride levels known to cause corrosion as well as from a control concrete. Beams were subjected to freeze-thaw or saltwater followed by repeated loading to simulate field conditions. The following characteristics were quantified: chance of corrosion, corrosion rate, chloride content, flexural response as a function of environmental exposure and repeated loads, and ultimate strength. The size of the porous zone around the reinforcement was determined using an environmental scanning electron microscope. Finally, a strategy was developed to assess if a bridge deck exhibited the characteristics associated with falling concrete. The strategy included visual inspection of cracking and spalling, assessment of chance of corrosion, chloride content, and pH levels. If any of these measures exceed critical levels a service life calculation needs to be performed. Based on existing mathematical models, the time to corrosion initiation and time to corrosion cracking can be predicted. The resulting time is then compared to the age of the bridge. From this information proper planning for future repair needs can be made.
Remove-and-replace with suitable material has been the primary solution used for improving subgra... more Remove-and-replace with suitable material has been the primary solution used for improving subgrades in Michigan, USA, when weak subgrades are encountered in road construction. Considering the large extent of silty and clayey soils found in southeastern Michigan, where much of the population and the roads are located within the state, the earthwork associated with this solution is massive and expensive. The use of cement kiln dust (CKD) or lime kiln dust (LKD) as a subgrade stabilizer can be a cost-effective solution if there is sufficient evidence to prove that such stabilization is suitable for the soils and the climate in southeastern Michigan. This became the subject of a field and laboratory investigation carried out in Michigan and sponsored by the Michigan Department of Transportation. The findings from the laboratory portion of this research (which were published in a separate manuscript) proved CKD’s suitability for long-term stabilization and LKD’s capacity for being a sta...
The tire-pavement friction is drastically reduced during winter storm events. Loss of tire paveme... more The tire-pavement friction is drastically reduced during winter storm events. Loss of tire pavement friction during winter storms causes severe safety hazard to the motoring public. Every year more than 117,000 people are injured and more than 1,300 people have died on snowy, slushy or icy roadways (1). The coefficient of friction between the vehicle tire and the pavement can be dramatically improved by winter maintenance activities such as snow plowing, deicing, anti-icing and sanding of the roadway. Although in the United States friction testing is not primarily used as a winter performance measure, a number of European countries and Japan uses this technology regularly. Friction can be determined using three methods; predicting friction using climate, traffic and other roadway conditions, direct friction measurements using an extra wheel installed on vehicles, or by traction control systems. NCHRP Web Document 136 lists three operational uses of friction measuring devices in wint...
Abstract: An experimental and numerical research project was developed to address the effect of t... more Abstract: An experimental and numerical research project was developed to address the effect of the level of transverse post-tensioning (TPT) and the number of the transverse diaphragms on the performance of side-by-side box-beam bridges using unbonded carbon fiber composite cables (CFCC). The experimental program included the construction, instrumentation, and testing of one half-scaled 30 skew bridge model. The numerical program investigated the sensitivity to longitudinal cracking for a wide range of side-by- ...
Due to rising costs of good quality acceptable materials for remove/replace options and tradition... more Due to rising costs of good quality acceptable materials for remove/replace options and traditional subgrade stabilization materials, the Michigan Department of Transportation (MDOT) is in need to identify potential recycled materials to treat unacceptable subgrade soils. Use of recycled materials may not only provide less costly alternatives for subgrade stabilization, their use may also alleviate landfill disposal challenges. This research study is aimed at identifying short-term and long-term advantages and disadvantages associated with subgrade stabilization using recycled materials such as Cement Kiln Dust (CKD), Lime Kiln Dust (LKD), fly ash (FA), concrete fines and mixtures of LKD and FA. An extensive laboratory testing program was conducted to determine suitability of the above recycled stabilizers for subgrade stabilization for common problematic soils found in Michigan. The laboratory investigative program involved determining the basic soil properties, developing mix desi...
Adequate knowledge of the deformation and thermal characteristics of concrete throughout the fire... more Adequate knowledge of the deformation and thermal characteristics of concrete throughout the fire burning and decay phase is paramount to predict the deformation history of concrete structures subjected to fire. This paper presents new experimental data on the deformation of axially loaded plain concrete prisms as well as the thermal diffusivity of plain concrete slabs subjected to fire conditions. The concrete is designed as a normal strength, structural concrete with a design compressive strength of 50 MPa. When investigating the deformation characteristics the variables are: 1) stress ratio (0, 17, 33 and 50 %); defined by the ratio of applied axial stress and the cold compressive strength; and 2) maximum core temperature when cooling is induced (200, 400, 600 and 800!C). Deformations considered are the total free expansion as well as the total deformation comprised of thermal and transient strains, of loaded concrete. While the specimens are about twice that used in earlier stud...
The State of Michigan in the United States often encounters weak soil subgrades during its road c... more The State of Michigan in the United States often encounters weak soil subgrades during its road construction and maintenance activities. Undercutting has been the usual solution, while a very few attempts of in-situ soil stabilization with cement or lime have been made. Compared to the large volume of weak soils that require improvement and the cost incurred on an annual basis, some locally available industrial byproducts present the potential to become effective soil subgrade stabilizers and a better solution from the sustainability perspective as well. The candidate industrial byproducts are Cement Kiln Dust (CKD), Lime Kiln Dust (LKD), and Fly Ash (FA), out of which only a fraction is currently used for any other secondary purposes while the rest is disposed of in Michigan landfills. This manuscript describes a laboratory investigation conducted on above industrial byproducts and/or their combinations to assess their suitability to be used as soil subgrade stabilizers in three se...
Transportation Research Record Journal of the Transportation Research Board, Feb 2, 2015
Portland cement concrete fracture properties—specific fracture energy, fracture toughness, and br... more Portland cement concrete fracture properties—specific fracture energy, fracture toughness, and brittleness—were investigated for typical Michigan highway concretes containing different coarse aggregates and varying in age: 7,28, and 91 days. These fracture properties can be determined from the complete load-deflection curve of a notched beam. The effective beam is 965 mm long, 100 mm wide, and 200 mm high, with a 100-mm center notch. Results show that the specific fracture energy, which determines the resistance to crack propagation, for a concrete pavement mix is controlled primarily by the coarse aggregate type. Differences of 100 percent were obtained between aggregate types. A glacial gravel yielded the highest resistance (160 N/m), and the dolomitic limestones and blast furnace slag yielded the lowest resistance (80–100 N/m), although the concretes all had similar strength properties. The fracture toughness, resistance to crack initiation, was found to be linear related with concrete strength. Typically this results in improved early age fracture toughness for concretes containing dolomitic limestone and blast furnace slag as coarse aggregate, compared to glacial gravel, because natural aggregate concrete typically has slower strength gain initially. Concrete brittleness, based on the entire load-deflection response, showed that concretes containing stronger coarse aggregate, such as glacial gravel, are significantly less brittle at early ages than are concretes containing weaker aggregate. However, these stronger aggregate concretes become more brittle, and thus crack sensitive, over time.
This study developed a procedure to identify concrete bridge decks that are exhibiting the charac... more This study developed a procedure to identify concrete bridge decks that are exhibiting the characteristics associated with falling concrete. Field exploratory work on reinforced concrete bridge decks was supported by analytical and laboratory investigations. The field work included visual inspection, non-destructive tests, and sampling of full-depth cores and powder samples from the bottom of the bridge deck. Chief variables assessed were the chance of corrosion by the half-cell potential, chloride content at the location of the bottom reinforcement, and the concrete pH level. The chloride diffusivity was estimated from the chloride profile. The laboratory investigation was performed on bridge deck beams. The beams were constructed from concrete containing chloride levels known to cause corrosion as well as from a control concrete. Beams were subjected to freeze-thaw or saltwater followed by repeated loading to simulate field conditions. The following characteristics were quantified: chance of corrosion, corrosion rate, chloride content, flexural response as a function of environmental exposure and repeated loads, and ultimate strength. The size of the porous zone around the reinforcement was determined using an environmental scanning electron microscope. Finally, a strategy was developed to assess if a bridge deck exhibited the characteristics associated with falling concrete. The strategy included visual inspection of cracking and spalling, assessment of chance of corrosion, chloride content, and pH levels. If any of these measures exceed critical levels a service life calculation needs to be performed. Based on existing mathematical models, the time to corrosion initiation and time to corrosion cracking can be predicted. The resulting time is then compared to the age of the bridge. From this information proper planning for future repair needs can be made.
Remove-and-replace with suitable material has been the primary solution used for improving subgra... more Remove-and-replace with suitable material has been the primary solution used for improving subgrades in Michigan, USA, when weak subgrades are encountered in road construction. Considering the large extent of silty and clayey soils found in southeastern Michigan, where much of the population and the roads are located within the state, the earthwork associated with this solution is massive and expensive. The use of cement kiln dust (CKD) or lime kiln dust (LKD) as a subgrade stabilizer can be a cost-effective solution if there is sufficient evidence to prove that such stabilization is suitable for the soils and the climate in southeastern Michigan. This became the subject of a field and laboratory investigation carried out in Michigan and sponsored by the Michigan Department of Transportation. The findings from the laboratory portion of this research (which were published in a separate manuscript) proved CKD’s suitability for long-term stabilization and LKD’s capacity for being a sta...
The tire-pavement friction is drastically reduced during winter storm events. Loss of tire paveme... more The tire-pavement friction is drastically reduced during winter storm events. Loss of tire pavement friction during winter storms causes severe safety hazard to the motoring public. Every year more than 117,000 people are injured and more than 1,300 people have died on snowy, slushy or icy roadways (1). The coefficient of friction between the vehicle tire and the pavement can be dramatically improved by winter maintenance activities such as snow plowing, deicing, anti-icing and sanding of the roadway. Although in the United States friction testing is not primarily used as a winter performance measure, a number of European countries and Japan uses this technology regularly. Friction can be determined using three methods; predicting friction using climate, traffic and other roadway conditions, direct friction measurements using an extra wheel installed on vehicles, or by traction control systems. NCHRP Web Document 136 lists three operational uses of friction measuring devices in wint...
Abstract: An experimental and numerical research project was developed to address the effect of t... more Abstract: An experimental and numerical research project was developed to address the effect of the level of transverse post-tensioning (TPT) and the number of the transverse diaphragms on the performance of side-by-side box-beam bridges using unbonded carbon fiber composite cables (CFCC). The experimental program included the construction, instrumentation, and testing of one half-scaled 30 skew bridge model. The numerical program investigated the sensitivity to longitudinal cracking for a wide range of side-by- ...
Due to rising costs of good quality acceptable materials for remove/replace options and tradition... more Due to rising costs of good quality acceptable materials for remove/replace options and traditional subgrade stabilization materials, the Michigan Department of Transportation (MDOT) is in need to identify potential recycled materials to treat unacceptable subgrade soils. Use of recycled materials may not only provide less costly alternatives for subgrade stabilization, their use may also alleviate landfill disposal challenges. This research study is aimed at identifying short-term and long-term advantages and disadvantages associated with subgrade stabilization using recycled materials such as Cement Kiln Dust (CKD), Lime Kiln Dust (LKD), fly ash (FA), concrete fines and mixtures of LKD and FA. An extensive laboratory testing program was conducted to determine suitability of the above recycled stabilizers for subgrade stabilization for common problematic soils found in Michigan. The laboratory investigative program involved determining the basic soil properties, developing mix desi...
Adequate knowledge of the deformation and thermal characteristics of concrete throughout the fire... more Adequate knowledge of the deformation and thermal characteristics of concrete throughout the fire burning and decay phase is paramount to predict the deformation history of concrete structures subjected to fire. This paper presents new experimental data on the deformation of axially loaded plain concrete prisms as well as the thermal diffusivity of plain concrete slabs subjected to fire conditions. The concrete is designed as a normal strength, structural concrete with a design compressive strength of 50 MPa. When investigating the deformation characteristics the variables are: 1) stress ratio (0, 17, 33 and 50 %); defined by the ratio of applied axial stress and the cold compressive strength; and 2) maximum core temperature when cooling is induced (200, 400, 600 and 800!C). Deformations considered are the total free expansion as well as the total deformation comprised of thermal and transient strains, of loaded concrete. While the specimens are about twice that used in earlier stud...
The State of Michigan in the United States often encounters weak soil subgrades during its road c... more The State of Michigan in the United States often encounters weak soil subgrades during its road construction and maintenance activities. Undercutting has been the usual solution, while a very few attempts of in-situ soil stabilization with cement or lime have been made. Compared to the large volume of weak soils that require improvement and the cost incurred on an annual basis, some locally available industrial byproducts present the potential to become effective soil subgrade stabilizers and a better solution from the sustainability perspective as well. The candidate industrial byproducts are Cement Kiln Dust (CKD), Lime Kiln Dust (LKD), and Fly Ash (FA), out of which only a fraction is currently used for any other secondary purposes while the rest is disposed of in Michigan landfills. This manuscript describes a laboratory investigation conducted on above industrial byproducts and/or their combinations to assess their suitability to be used as soil subgrade stabilizers in three se...
Transportation Research Record Journal of the Transportation Research Board, Feb 2, 2015
Portland cement concrete fracture properties—specific fracture energy, fracture toughness, and br... more Portland cement concrete fracture properties—specific fracture energy, fracture toughness, and brittleness—were investigated for typical Michigan highway concretes containing different coarse aggregates and varying in age: 7,28, and 91 days. These fracture properties can be determined from the complete load-deflection curve of a notched beam. The effective beam is 965 mm long, 100 mm wide, and 200 mm high, with a 100-mm center notch. Results show that the specific fracture energy, which determines the resistance to crack propagation, for a concrete pavement mix is controlled primarily by the coarse aggregate type. Differences of 100 percent were obtained between aggregate types. A glacial gravel yielded the highest resistance (160 N/m), and the dolomitic limestones and blast furnace slag yielded the lowest resistance (80–100 N/m), although the concretes all had similar strength properties. The fracture toughness, resistance to crack initiation, was found to be linear related with concrete strength. Typically this results in improved early age fracture toughness for concretes containing dolomitic limestone and blast furnace slag as coarse aggregate, compared to glacial gravel, because natural aggregate concrete typically has slower strength gain initially. Concrete brittleness, based on the entire load-deflection response, showed that concretes containing stronger coarse aggregate, such as glacial gravel, are significantly less brittle at early ages than are concretes containing weaker aggregate. However, these stronger aggregate concretes become more brittle, and thus crack sensitive, over time.
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