Matching Items (14)

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Donation-Based Concrete Placement: SVDP Elementary School

Description

Using the Arizona State University chapter of American Concrete Institute (ACI) as my platform, I recently teamed up with several generous companies to donate a new picnic slab and sidewalks to St. Vincent de Paul Elementary School's playground. Material/labor donations

Using the Arizona State University chapter of American Concrete Institute (ACI) as my platform, I recently teamed up with several generous companies to donate a new picnic slab and sidewalks to St. Vincent de Paul Elementary School's playground. Material/labor donations from Suntec Concrete, Arizona Materials, Salt River Materials Group, and Dickens Quality Demolition made it possible to complete this project over the course of two Saturdays and at no cost for the school. In addition to the children of St. Vincent de Paul's benefit, this project also gave ASU and MCC students the opportunity to work in the field with industry professionals and gain hands-on experience. Over 20 students were able to witness and participate in demolition, formwork, concrete placement (including a laser screed appearance provided by Suntec), finishing, sawcutting, and more. As for specifics, the project featured a 19' x 40' picnic slab, as well as two 6' wide sidewalks connecting the slab to the playground and the playground to the adjacent access road. Once the second sidewalk reached the access road, it continued to the classrooms with 6' wide ramps on each side for truck accessibility. My role in this project was essentially a superintendent. I served as the primary point of contact for all parties involved, organized the material and labor donations, coordinated the project schedule, and kept all companies informed of the schedule to ensure proper execution and avoid delays. Due to various unavoidable conditions (cold weather, shade on the slab, etc.), I was also forced to make a few critical decisions as the project progressed.

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Created

Date Created
2018-05

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Mechanical and Thermal Properties of Copper Slag Concrete

Description

In this investigation, copper slag was used as a coarse aggregate in four different mixes of concrete, consisting of 0%, 25%, 50%, and 100% copper slag by volume. Locally available Salt river aggregate was used as a control, and mixes

In this investigation, copper slag was used as a coarse aggregate in four different mixes of concrete, consisting of 0%, 25%, 50%, and 100% copper slag by volume. Locally available Salt river aggregate was used as a control, and mixes were tested for density, strength, thermal conductivity, specific heat capacity, and thermal diffusivity. Density was shown to increase with increasing copper slag content, increasing an average of 2298 kg/m^3, 2522 kg/m^3, and 2652 kg/m^3 in the 25%, 50%, and 100% mixes. This represents a 15% increase in density from 0% to 100%. Compressive strength testing indicated that the presence of copper slag in concrete provides no definitive strength benefit over Salt River aggregate. This result was expected, as concrete's strength is primarily derived from the cement matrix and not the aggregate. Thermal conductivity showed a decreasing trend with increasing copper slag content. Th control mix had an average conductivity of 0.660 W/m*K, and the 25%, 50%, and 100% mixes had conductivities of 0.649 W/m*K, 0.647 W/m*K, and 0.519 W/m*K, respectively. This represents 21% drop in thermal conductivity over the control. This result was also expected, as materials formed at higher temperatures, like copper slag, tend to have lower thermal conductivities. Specific heat capacity testing yielded results that were statistically indeterminate, though unlike strength testing this arose from inaccurate assumptions made during testing. This also prevented accurate thermal diffusivity results, as diffusivity is a function of density, thermal conductivity, and specific heat capacity. However, given the trends of the first two parameters, it is plausible to say that diffusivity in copper slag concrete would be lower than that of the control ix. All of these results were plugged into ASU's Pavement Temperature Model to see what effect they had in mitigating the UHI effect.

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Created

Date Created
2012-05

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Development of an Automated Pultrusion System for Manufacturing of Textile Reinforced Cementitious Composites

Description

Concrete stands at the forefront of the construction industry as one of the most useful building materials. Economic and efficient improvements in concrete strengthening and manufacturing are widely sought to continuously improve the performance of the material. Fiber reinforcement is

Concrete stands at the forefront of the construction industry as one of the most useful building materials. Economic and efficient improvements in concrete strengthening and manufacturing are widely sought to continuously improve the performance of the material. Fiber reinforcement is a significant technique in strengthening precast concrete, but manufacturing limitations are common which has led to reliance on steel reinforcement. Two-dimensional textile reinforcement has emerged as a strong and efficient alternative to both fiber and steel reinforced concrete with pultrusion manufacturing shown as one of the most effective methods of precasting concrete. The intention of this thesis project is to detail the components, functions, and outcomes shown in the development of an automated pultrusion system for manufacturing textile reinforced concrete (TRC). Using a preexisting, manual pultrusion system and current-day manufacturing techniques as a basis, the automated pultrusion system was designed as a series of five stations that centered on textile impregnation, system driving, and final pressing. The system was then constructed in the Arizona State University Structures Lab over the course of the spring and summer of 2015. After fabricating each station, a computer VI was coded in LabVIEW software to automatically drive the system. Upon completing construction of the system, plate and angled structural sections were then manufactured to verify the adequacy of the technique. Pultruded TRC plates were tested in tension and flexure while full-scale structural sections were tested in tension and compression. Ultimately, the automated pultrusion system was successful in establishing an efficient and consistent manufacturing process for continuous TRC sections.

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Created

Date Created
2016-05

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Creating Industry-Based Marketing Materials and Instruments for University Academic Programs

Description

This thesis explores the task of creating industry-based marketing materials to assist academic programs in their recruitment of high school and community college students. With consistent reductions to public university budgets there is an increasing pressure on academic programs to

This thesis explores the task of creating industry-based marketing materials to assist academic programs in their recruitment of high school and community college students. With consistent reductions to public university budgets there is an increasing pressure on academic programs to raise their student enrollment figures, as student count is often cited as one of the most important statistics when making budget decisions. Many academic programs are ill-equipped to perform this task, however, as their personnel are not trained as recruiters, but rather as professors and industry professionals; furthermore, the university-level recruitment staff faces the impossible task of advertising every department's recruitment message. The Del E. Webb School of Construction has embarked upon a journey to create industry-based marketing materials to aid them in their recruitment efforts. Construction management (CM) has traditionally been viewed as a technology major relegated to vocational students and those not fit for baccalaureate programs. In recent years that perception has changed, however, as the industry has become increasingly complex and CM programs actively work to recruit students. In an attempt to increase that recruitment, the Del E. Webb School has created marketing materials that are signature to the program featuring the world's most widely-used building material, concrete, to create a keepsake for prospective students. This keepsake comes in the form of concrete replicas of the new ASU Pitchfork logo. These pitchforks are small and designed to be mass produced so that they can be handed out at recruitment events either on campus or in local schools. The Del E. Webb School had previously experimented with flexible rubber molds and flowable mixtures, such that the models could be easily cast and rapidly demolded and reset for casting. There were issues, however, as those pitchforks did not meet desired level of quality and were difficult to reproduce. This thesis thus describes an experimental program examining different casting and demolding regimens in an attempt to find the optimal way to create the pitchforks on a consistent basis. Following this, an operations manual for how to create the pitchforks was created in order to ensure that successive cohorts of construction students can reproduce the pitchforks in preparation for the School's annual recruitment events.

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Created

Date Created
2014-05

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Effects of Aggregate Packing Density on the Mechanical Properties of Ultra-High Performance Concrete

Description

Cement is a remarkable construction material that allows for the formation of complex geometric forms while still providing adequate strength properties to be used as a structural material. This research focuses on Ultra-High Performance Concrete (UHPC) which is a specialized

Cement is a remarkable construction material that allows for the formation of complex geometric forms while still providing adequate strength properties to be used as a structural material. This research focuses on Ultra-High Performance Concrete (UHPC) which is a specialized class of cementitious material that exhibits exceptional strength and durability properties when compared to standard concrete. UHPC achieves these properties through a combination of high cement content, high particle packing density, low water-to-cement ratio, and the additional of special admixtures such as superplasticizer. These components all serve the purpose of increasing UHPC strength and mechanical properties by helping achieve much high material densities than other forms of concrete.
In this study, aggregate material evaluation and testing was conducted for use in the mix design of the UHPC mixes that were carried out and tested. Each mix employed the same general UHPC mixture design with the only difference being the aggregate proportions of #4, #8, and #10 nominal size aggregates. The purpose of using a UHPC mix design that was independent of aggregate proportioning was to evaluate the effects of varying aggregate particle packing densities. Increased particle packing density of UHPC provide improved mechanical performance by decreasing the distance between particle within cured UHPC, thereby producing significant increases in compressive strength, tensile strength, durability, and service life of UHPC when compared to standard concrete. For this study, particle packing densities of 0.509, 0.521, 0.540, and 0.552 were employed and evaluated on the basis of compressive strength and tensile strength to determine the optimum UHPC mix design.

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Created

Date Created
2019-05

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Lighter Concrete: An In-Depth Analysis of the Effects of Recycled Plastic Aggregate in Composite Concrete

Description

The scope of this project is a combination of material science engineering and mechanical engineering. Overall, the main goal of this project is to develop a lightweight concrete that maintains its original strength profile. Initial research has shown that a

The scope of this project is a combination of material science engineering and mechanical engineering. Overall, the main goal of this project is to develop a lightweight concrete that maintains its original strength profile. Initial research has shown that a plastic-concrete composite could create a more lightweight concrete than that made using the typical gravel aggregate for concrete, while still maintaining the physical strength that concrete is known for. This will be accomplished by varying the amount of plastic in the aggregate. If successful, this project would allow concrete to be used in applications it would typically not be suitable for.<br/>After testing the strength of the concrete specimens with varying fills of plastic aggregate it was determined that the control group experienced an average peak stress of 2089 psi, the 16.67% plastic group experienced an average peak stress of 2649 psi, the 33.3% plastic group experienced an average peak stress of 1852 psi, and the 50% plastic group experienced an average stress of 924.5 psi. The average time to reach the peak stress was found to be 12 minutes and 24 seconds in the control group, 15 minutes and 34 seconds in the 16.7% plastic group, 9 minutes and 45 seconds in the 33.3% plastic group, and 10 minutes and 58 seconds in the 50% plastic group. Taking the average of the normalized weights of the cylindrical samples it was determined that the control group weighed 14.773 oz/in, the 16.7% plastic group weighed 15 oz/in, the 33.3% plastic group weighed 14.573 oz/in, and the 50% plastic group weighed 12.959 oz/in. Based on these results it can be concluded that a small addition of plastic aggregate can be beneficial in creating a lighter, stronger concrete. The results show that a 16.7% fill ratio of plastic to rock aggregate can increase the failure time and the peak strength of a composite concrete. Overall, the experiment was successful in analyzing the effects of recycled plastic aggregate in composite concrete. <br/>Some possible future studies related to this subject material are adding aluminum to the concrete, having better molds, looking for the right consistency in each mixture, mixing for each mold individually, and performing other tests on the samples.

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Created

Date Created
2021-05

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Lighter Concrete: An In-Depth Analysis of the Effects of Recycled Plastic Aggregate in Composite Concrete

Description

The scope of this project is a combination of material science engineering and<br/>mechanical engineering. Overall, the main goal of this project is to develop a lightweight<br/>concrete that maintains its original strength profile. Initial research has shown that a<br/>plastic-concrete composite could

The scope of this project is a combination of material science engineering and<br/>mechanical engineering. Overall, the main goal of this project is to develop a lightweight<br/>concrete that maintains its original strength profile. Initial research has shown that a<br/>plastic-concrete composite could create a more lightweight concrete than that made using the<br/>typical gravel aggregate for concrete, while still maintaining the physical strength that concrete is<br/>known for. This will be accomplished by varying the amount of plastic in the aggregate. If<br/>successful, this project would allow concrete to be used in applications it would typically not be<br/>suitable for.<br/>After testing the strength of the concrete specimens with varying fills of plastic aggregate<br/>it was determined that the control group experienced an average peak stress of 2089 psi, the<br/>16.67% plastic group experienced an average peak stress of 2649 psi, the 33.3% plastic group<br/>experienced an average peak stress of 1852 psi, and the 50% plastic group experienced an<br/>average stress of 924.5 psi. The average time to reach the peak stress was found to be 12 minutes<br/>and 24 seconds in the control group, 15 minutes and 34 seconds in the 16.7% plastic group, 9<br/>minutes and 45 seconds in the 33.3% plastic group, and 10 minutes and 58 seconds in the 50%<br/>plastic group. Taking the average of the normalized weights of the cylindrical samples it was<br/>determined that the control group weighed 14.773 oz/in, the 16.7% plastic group weighed 15<br/>oz/in, the 33.3% plastic group weighed 14.573 oz/in, and the 50% plastic group weighed 12.959<br/>oz/in. Based on these results it can be concluded that a small addition of plastic aggregate can be<br/>beneficial in creating a lighter, stronger concrete. The results show that a 16.7% fill ratio of<br/>plastic to rock aggregate can increase the failure time and the peak strength of a composite<br/>concrete. Overall, the experiment was successful in analyzing the effects of recycled plastic<br/>aggregate in composite concrete.<br/>Some possible future studies related to this subject material are adding aluminum to the<br/>concrete, having better molds, looking for the right consistency in each mixture, mixing for each<br/>mold individually, and performing other tests on the samples.

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Created

Date Created
2021-05

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Toughness based analysis and design of fiber reinforced concrete

Description

Concrete design has recently seen a shift in focus from prescriptive specifications to performance based specifications with increasing demands for sustainable products. Fiber reinforced composites (FRC) provides unique properties to a material that is very weak under tensile loads. The

Concrete design has recently seen a shift in focus from prescriptive specifications to performance based specifications with increasing demands for sustainable products. Fiber reinforced composites (FRC) provides unique properties to a material that is very weak under tensile loads. The addition of fibers to a concrete mix provides additional ductility and reduces the propagation of cracks in the concrete structure. It is the fibers that bridge the crack and dissipate the incurred strain energy in the form of a fiber-pullout mechanism. The addition of fibers plays an important role in tunnel lining systems and in reducing shrinkage cracking in high performance concretes. The interest in most design situations is the load where cracking first takes place. Typically the post crack response will exhibit either a load bearing increase as deflection continues, or a load bearing decrease as deflection continues. These behaviors are referred to as strain hardening and strain softening respectively. A strain softening or hardening response is used to model the behavior of different types of fiber reinforced concrete and simulate the experimental flexural response. Closed form equations for moment-curvature response of rectangular beams under four and three point loading in conjunction with crack localization rules are utilized. As a result, the stress distribution that considers a shifting neutral axis can be simulated which provides a more accurate representation of the residual strength of the fiber cement composites. The use of typical residual strength parameters by standards organizations ASTM, JCI and RILEM are examined to be incorrect in their linear elastic assumption of FRC behavior. Finite element models were implemented to study the effects and simulate the load defection response of fiber reinforced shotcrete round discrete panels (RDP's) tested in accordance with ASTM C-1550. The back-calculated material properties from the flexural tests were used as a basis for the FEM material models. Further development of FEM beams were also used to provide additional comparisons in residual strengths of early age samples. A correlation between the RDP and flexural beam test was generated based a relationship between normalized toughness with respect to the newly generated crack surfaces. A set of design equations are proposed using a residual strength correction factor generated by the model and produce the design moment based on specified concrete slab geometry.

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Created

Date Created
2011

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Pavement temperature effects on overall urban heat island

Description

In recent years, an increase of environmental temperature in urban areas has raised many concerns. These areas are subjected to higher temperature compared to the rural surrounding areas. Modification of land surface and the use of materials such as concrete

In recent years, an increase of environmental temperature in urban areas has raised many concerns. These areas are subjected to higher temperature compared to the rural surrounding areas. Modification of land surface and the use of materials such as concrete and/or asphalt are the main factors influencing the surface energy balance and therefore the environmental temperature in the urban areas. Engineered materials have relatively higher solar energy absorption and tend to trap a relatively higher incoming solar radiation. They also possess a higher heat storage capacity that allows them to retain heat during the day and then slowly release it back into the atmosphere as the sun goes down. This phenomenon is known as the Urban Heat Island (UHI) effect and causes an increase in the urban air temperature. Many researchers believe that albedo is the key pavement affecting the urban heat island. However, this research has shown that the problem is more complex and that solar reflectivity may not be the only important factor to evaluate the ability of a pavement to mitigate UHI. The main objective of this study was to analyze and research the influence of pavement materials on the near surface air temperature. In order to accomplish this effort, test sections consisting of Hot Mix Asphalt (HMA), Porous Hot Mix asphalt (PHMA), Portland Cement Concrete (PCC), Pervious Portland Cement Concrete (PPCC), artificial turf, and landscape gravels were constructed in the Phoenix, Arizona area. Air temperature, albedo, wind speed, solar radiation, and wind direction were recorded, analyzed and compared above each pavement material type. The results showed that there was no significant difference in the air temperature at 3-feet and above, regardless of the type of the pavement. Near surface pavement temperatures were also measured and modeled. The results indicated that for the UHI analysis, it is important to consider the interaction between pavement structure, material properties, and environmental factors. Overall, this study demonstrated the complexity of evaluating pavement structures for UHI mitigation; it provided great insight on the effects of material types and properties on surface temperatures and near surface air temperature.

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Created

Date Created
2013

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Optimization of the prestressing force in continuous concrete bridges

Description

Most engineers may agree that an optimum design of a particular structure is a proposal that minimizes costs without compromising resistance, serviceability and aesthetics. Additionally to these conditions, the theory and application of the method that produces such an efficient

Most engineers may agree that an optimum design of a particular structure is a proposal that minimizes costs without compromising resistance, serviceability and aesthetics. Additionally to these conditions, the theory and application of the method that produces such an efficient design must be easy and fast to apply at the structural engineering offices.

A considerable amount of studies have been conducted for the past four decades. Most researchers have used constraints and tried to minimize the cost of the structure by reducing the weight of it [8]. Although this approach may be true for steel structures, it is not accurate for composite structures such as reinforced and prestressed concrete. Maximizing the amount of reinforcing steel to minimize the weight of the overall structure can produce an increase of the cost if the price of steel is too high compared to concrete [8]. A better approach is to reduce the total cost of the structure instead of weight. However, some structures such as Prestressed Concrete AASHTO Girders have been standardized with the purpose of simplifying production, design and construction. Optimizing a bridge girder requires good judgment at an early stage of the design and some studies have provided guides for preliminary design that will generate a final economical solution [17] [18]. Therefore, no calculations or optimization procedure is required to select the appropriate Standard AASHTO Girder. This simplifies the optimization problem of a bridge girder to reducing the amount of prestressing and mild steel only. This study will address the problem of optimizing the prestressing force of a PC AASHTO girder by using linear programming and feasibility domain of working stresses. A computer program will be presented to apply the optimization technique effectively.

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Created

Date Created
2016