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Articles 151 - 180 of 200

Full-Text Articles in Civil Engineering

The Quantification Of The Fly Ash Adsorption Capacity For The Purpose Of Characterization And Use In Concrete, Zeyad Tareq Ahmed Jan 2012

The Quantification Of The Fly Ash Adsorption Capacity For The Purpose Of Characterization And Use In Concrete, Zeyad Tareq Ahmed

Dissertations, Master's Theses and Master's Reports - Open

Fly ash has been shown to be an effective replacement for portland cement in concrete mixtures. However, many fly ash materials contain unburned carbon from the combustion process. Unburned carbon in fly ash adsorbs air entraining admixtures (AEAs) reducing their effectiveness in providing a specified air void system in concrete materials. Measurement tools and methods for characterization of the adsorption properties of fly ash materials are necessary for beneficial use of fly ash materials in concrete. In this research, two methods were developed to measure and quantify the adsorption capacity AEAs on fly ash materials. The first method is the …


Strengthening Of Reinforced Concrete Beams Pre-Damaged In Shear, Yousef Mohammed Bachar Chekfeh Jan 2012

Strengthening Of Reinforced Concrete Beams Pre-Damaged In Shear, Yousef Mohammed Bachar Chekfeh

Theses

Repair and strengthening of existing reinforced concrete (RC) structures has increased drastically in recent years. Shear reinforcement in RC beams is typically of a small bar diameter, and hence any shear-damage would result in a severe safety hazard and a catastrophic mode of failure especially under extreme loading events. The present work was initiated to the effectiveness of different composite strengthening systems; namely externally bonded carbon fiber reinforced polymer (EB-CFRP), and near surface mounted glass fiber reinforced polymer (NSM-GFRP) to prolong the functional service life of RC beams pre-damaged in shear. It comprised experimental testing and analytical investigation.

The experimental …


Development Of A Structured Concrete Thermocline Thermal Energy Storage System, Bradley M. Brown Dec 2011

Development Of A Structured Concrete Thermocline Thermal Energy Storage System, Bradley M. Brown

Graduate Theses and Dissertations

The past couple of decades have shown a concern when considering the way the world obtains its power. The focus has been switching from fossil fuels that have been used for hundreds of years to renewable energy sources, such as the sun. Solar energy is readily and infinitely available for harnessing. One problem with solar energy, though, is its inability to be used during the night time and during cloud covered weather. A solution to this problem is the use of energy storage mechanisms. For solar plants that use solar thermal energy (concentrating solar power plants), thermal energy storage (TES) …


Retrofit Solutions For Sealed Pervious Concrete Pavements, Gregory Bunting Aug 2011

Retrofit Solutions For Sealed Pervious Concrete Pavements, Gregory Bunting

All Theses

The goal of this research was to design, implement, and evaluate several retrofit solutions for sealed pervious concrete. Properly functioning pervious concrete pavements allow water to drain through the structure, eliminating the need for traditional drainage infrastructure. A recent study of South Carolina porous pavements (Putman 2010) revealed that some pervious concrete pavements are not properly draining, either because of sealing at the surface. Sealed pavements are generally a result of construction processes, and sealed pavements cannot be fixed with sediment removal techniques such as vacuuming and pressure washing. This study investigates a technique to increase infiltration of sealed pervious …


Investigation Into The Role Of Airfield Pavement Deicer In Concrete Pavement Deterioration, David Wingard Aug 2011

Investigation Into The Role Of Airfield Pavement Deicer In Concrete Pavement Deterioration, David Wingard

All Dissertations

Premature deterioration of concrete due to materials-related distresses has been observed with increased frequency in airfield pavements across the United States in the past two decades. The use of a new breed of deicing chemicals based on alkali-acetates and alkali-formates, starting in the early 1990s, has been suspected to be one of the significant reasons for the increase in the observed deterioration. Previous laboratory-based studies have found that the early-age deterioration in concrete is associated with exposure to deicers causing acceleration of the Alkali Silica Reaction (ASR) deterioration mechanism and consequent failure. However, no systematic forensic studies on the impact …


Piedras Blancas Light Station Vista Point Improvement Plan, Larissa Heeren, Reuben Juster, Annamarie Usher, John Rossi, Nick Mitchell Jun 2011

Piedras Blancas Light Station Vista Point Improvement Plan, Larissa Heeren, Reuben Juster, Annamarie Usher, John Rossi, Nick Mitchell

Mechanical Engineering

Piedras Blancas Light station Improvement Involved the design of two separate parking lot/vista point plans as well as the creation of a concrete Iron Ranger located near the gift shop on site.


Gis Based Pavement Maintenance: A Systematic Approach, Robert J. Kmetz Apr 2011

Gis Based Pavement Maintenance: A Systematic Approach, Robert J. Kmetz

Purdue Polytechnic Directed Projects

Abstract

According to 2008 Federal Highway Administration (FHWA) statistics, there are 2,734,102 miles of paved public roads in the United Sates, with an additional 1,324,245 miles of unpaved public roads.  Road conditions deteriorate with time as the result of weather effects, deicing salts, and vehicle loads.  The most common pavement distress includes cracking, rutting, and potholes.  These pavement defects must be repaired to restore the pavement to a satisfactory service level for road users. According to the FHWA, in 2006 approximately $54.2 billion dollars was spent on maintenance and expansion, just on U.S. highways alone.

Routine maintenance is a cost …


Improved Joining Method For Segmental Prestressed Structures, Ralph Warren Jensen Jan 2011

Improved Joining Method For Segmental Prestressed Structures, Ralph Warren Jensen

Open Access Theses & Dissertations

This dissertation addresses the need for more robust and materially efficient structures, specifically structures that absorb higher levels of energy, can self-erect and which have variable reaction capabilities. These structures can take much higher levels of strain and loading compared to current technologies in reinforced concrete and carbon fiber composites. These structures are made using a novel method of joining segmental elements. A great advantage with this segmental structural system is it's survivability under overloaded conditions. During an impact, or concentrated pressure load, the structure will wrap around the impact zone thereby widely distributing the contact stresses. This function or …


The Influence Of Different European Cements On The Transport And Early-Age Properties Of Concrete In The Cover-Zone, Niall Holmes, L. Basheer, S. Nanukuttan, Pam. Basheer, W. J. Carter, T. M. Chrisp, G. Starrs Nov 2010

The Influence Of Different European Cements On The Transport And Early-Age Properties Of Concrete In The Cover-Zone, Niall Holmes, L. Basheer, S. Nanukuttan, Pam. Basheer, W. J. Carter, T. M. Chrisp, G. Starrs

Conference papers

The use of in situ tests for performance based specification would require demonstration of their suitability to distinguish the quality of concrete. With the introduction of new European Standards for cements, this would mean concretes produced with these new cements should be classified for their quality using the performance tests. It is generally believed that transport properties of concrete are related to their durability and hence the measurement of these properties can form the basis of performance based specifications. This paper reports data indicating that transport properties measured at 28-days for concretes manufactured with different European cements and water-binder ratios …


Portland Cement Concrete Pavement Permeability Performance, Javier Castro, Robert Spragg, Phil Kompare, W. Jason Weiss Nov 2010

Portland Cement Concrete Pavement Permeability Performance, Javier Castro, Robert Spragg, Phil Kompare, W. Jason Weiss

JTRP Technical Reports

The objective of this project was to evaluate the transport properties of concrete pavement in the state of Indiana using common testing procedures. Specifically this work evaluated the absorption of water, the absorption of deicing solutions, and electrical conductivity. A series of concrete paving mixtures were tested to provide a range of values that were typical for the state of Indiana. While similar mixture proportions were used for the mixtures in Indiana differences in the magnitude of water absorbed occurred. A series of mortars were tested to illustrate the effect of curing conditions, water to cement ratio, and paste volume. …


Developments In Intelligent Monitoring Of Concrete Structures, T. M. Chrisp, G. Starrs, W. J. Mccarter, E. H. Owens, S. V. Nanukuttan, Niall Holmes, L. Basheer Jun 2010

Developments In Intelligent Monitoring Of Concrete Structures, T. M. Chrisp, G. Starrs, W. J. Mccarter, E. H. Owens, S. V. Nanukuttan, Niall Holmes, L. Basheer

Conference papers

Deterioration in concrete comprises an initiation period and a propagation period. The initiation period is characterised by changes that occur within the concrete in response to the exposure environment and continues until a stage is reached when damage begins to propagate. The propagation period begins at a point in time defined when a particular event occurs (e.g. loss of steel passivity due to chloride ingress) and continues until a specified limit state is reached. The initiation and propagation stages of a deterioration process result from a complex interaction of physical, chemical and electrochemical phenomena. Prediction of the field performance of …


High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials, Mateusz Radlinski, Jan Olek Apr 2010

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials, Mateusz Radlinski, Jan Olek

JTRP Technical Reports

The purpose of this research was to examine the applicability of ternary binder systems containing ordinary portland cement (OPC), class C fly ash (FA) and silica fume (SF) for bridge deck concrete. This was accomplished in two parts, the laboratory part and a field application part.

During the laboratory studies, four ternary mixtures, each containing either 20% or 30% FA and either 5% or 7% SF were subjected to four different curing regimes (air drying, 7 days curing compound application and 3 or 7 days wet burlap curing). In general, all four ternary mixtures exhibited very good water and chloride …


The Use Of Novel Non-Destructive Methods For Quality Control And Performance Evaluation Of Concrete Structures, Sree Nanukuttan, Niall Holmes, Sudarsan Srininvasan, Lulu Basheer, Muhammed Basheer, John Mccarter, Gerry Starrs Jan 2010

The Use Of Novel Non-Destructive Methods For Quality Control And Performance Evaluation Of Concrete Structures, Sree Nanukuttan, Niall Holmes, Sudarsan Srininvasan, Lulu Basheer, Muhammed Basheer, John Mccarter, Gerry Starrs

Conference papers

Concrete cover provides the first line of defense against the ingress of many deleterious substances into the concrete. Therefore, a measure of its transport properties is vital in assessing its long term performance in a given exposure condition. In new structures the rate of ingress of the deleterious substances could be monitored using array of electrical sensors that are embedded in the cover concrete. For structures that are currently in service, tests can be performed by removing cores from the structure (lab based tests) or by using tests that can be performed on the surface (in situ tests). Results relating …


Developments In Monitoring Techniques For Durability Assessment Of Cover-Zone Concrete, W.J. Mccarter, T. M. Chrisp, G. Starrs, Niall Holmes, L. Basheer, M. Basheer, S. V. Nanukuttan Jan 2010

Developments In Monitoring Techniques For Durability Assessment Of Cover-Zone Concrete, W.J. Mccarter, T. M. Chrisp, G. Starrs, Niall Holmes, L. Basheer, M. Basheer, S. V. Nanukuttan

Conference papers

This paper outlines developments in the use of an embedded multi-electrode sensor to study the response of the cover-zone (surface 50mm) to the changing ambient environment. The sensor enables the measurement of the spatial and temporal distribution of the electrical properties of concrete and temperature within the cover-zone thereby allowing an integrated assessment of cover-zone concrete performance. Both laboratory and field results are presented to highlight the information that can be obtained from embedded sensors. When exposed to the natural environment, the temperature dependence of the electrical response is highlighted and standardization protocols are developed to account for this effect. …


Performance Of Reinforced Concrete Columns Strengthened With Fiber Reinforced Polymers Under Various Loading Conditions, Mohamed Gamal Mohamed El Sayed Jan 2010

Performance Of Reinforced Concrete Columns Strengthened With Fiber Reinforced Polymers Under Various Loading Conditions, Mohamed Gamal Mohamed El Sayed

Theses

Strengthening of reinforced concrete (RC) structures with Carbon Fiber Reinforced Polymer (CFRP) composites has been a popular subject that attracted considerable attention from researchers for the last two decades. The high specific strength, stiffness, environmental resistance, and ease of application make CFRP composites highly desirable for strengthening and rehabilitation of RC structural components.

For concentrically loaded RC members with a circular cross-section, the lateral CFRP-confinement of concrete results in a substantial increase in load capacity and ductility. CFRP-confinement is less effective for RC compression members with square and rectangular cross-sections due to stress concentration at the corners and lack of …


Frp Confined Reinforced Concrete Circular Cross Section Seismic Applications, Jeffrey G. Lyon Aug 2009

Frp Confined Reinforced Concrete Circular Cross Section Seismic Applications, Jeffrey G. Lyon

Master's Theses

In recent earthquakes, structures have not performed as well as expected resulting in a need for better means of retrofitting and improvements in seismic design. Fiber Reinforced Polymers (FRP), as a material with potential to increase strength and ductility of columns in conjunction with capacity design methodology, has promise for seismic design. By investigating the displacement, ductility, and flexural strength properties of FRP confined reinforced concrete circular cross sections, this study analyzes the seismic applications of FRP confinement.

The study is performed by incorporating an FRP confined concrete stress-strain model into a developed Moment-Curvature and PM Interaction software. This software …


Performance-Based Testing Methodology For Concrete Durability, Niall Holmes, P. A.Muhammed Basheer, Sreejith Nanukuttan, Lulu Basheer Jun 2009

Performance-Based Testing Methodology For Concrete Durability, Niall Holmes, P. A.Muhammed Basheer, Sreejith Nanukuttan, Lulu Basheer

Reports

This report presents an overview of performance based testing methodology for concrete durability and work currently underway jointly at Queens University Belfast and Heriot Watt University, Edinburgh, to undertake this research under a EPSRC funded project (EP/G02152X/1).

EN206-1 superseded BS 5328 on 1st December 2003 and allows designers and producers to use a wide range of cements and aggregate types for a variety of exposure conditions. In this new standard, the durability of concrete is specified in terms of the constituent materials of concrete, properties of fresh and hardened concrete, limitations for concrete composition, specification of concrete, delivery of …


Testing And Monitoring Concrete Using Novel Methods For Predicting Their Long Term Behaviour, Sreejith Nanukuttan, Lulu Basheer, Muhammed Basheer, Niall Holmes, John Mccarter, Malcolm Chrisp, Gerry Starrs May 2009

Testing And Monitoring Concrete Using Novel Methods For Predicting Their Long Term Behaviour, Sreejith Nanukuttan, Lulu Basheer, Muhammed Basheer, Niall Holmes, John Mccarter, Malcolm Chrisp, Gerry Starrs

Conference papers

It is widely recognised that durability of concrete depends on its transport properties, viz. absorption, diffusion and permeability. As concrete cover provides the first line of defence against the ingress of many deleterious substances into the concrete, a measure of its transport properties is vital in assessing its long term performance in the given exposure condition. In new structures the rate of ingress of the deleterious substances could be monitored using array of electrical sensors which are embedded in the cover concrete. For structures which are currently in service, two in situ permeability apparatuses, viz. Autoclam Permeability System (for measuring …


Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 1: Executive Summary, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan Jan 2009

Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 1: Executive Summary, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan

JTRP Technical Reports

Performance-Related Specifications (PRS) are specifications that base pavement acceptance and pay adjustment on the projected performance and predicted life-cycle cost (LCC) for a specific pavement. PRS relate measurable quality characteristics with pavement performance through computer simulations that incorporate physical distress models. Previously, work at ERES consultants by Darter and co-workers developed prototype PRS for jointed plain portland cement concrete pavements (PCC) through Federal Highway Administration (FHWA) through a series of research projects. However, before this research program began, pavements have not been constructed using these specifications. This report describes the Indiana Department of Transportation’s (INDOT) experience with developing and implementing …


Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 2: Technical Report, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan Jan 2009

Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 2: Technical Report, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan

JTRP Technical Reports

Performance-Related Specifications (PRS) are specifications that base pavement acceptance and pay adjustment on the projected performance and predicted life-cycle cost (LCC) for a specific pavement. PRS relate measurable quality characteristics with pavement performance through computer simulations that incorporate physical distress models. Previously, work at ERES consultants by Darter and co-workers developed prototype PRS for jointed plain portland cement concrete pavements (PCC) through Federal Highway Administration (FHWA) through a series of research projects. However, before this research program began, pavements have not been constructed using these specifications. This report describes the Indiana Department of Transportation’s (INDOT) experience with developing and implementing …


Saw-Cutting Guidelines For Concrete Pavements: Examining The Requirements For Time And Depth Of Saw-Cutting, Kambiz Raoufi, Tony Their, W. Jason Weiss, Jan Olek, Tommy E. Nantung Jan 2009

Saw-Cutting Guidelines For Concrete Pavements: Examining The Requirements For Time And Depth Of Saw-Cutting, Kambiz Raoufi, Tony Their, W. Jason Weiss, Jan Olek, Tommy E. Nantung

JTRP Technical Reports

Joints are placed in Portland cement concrete pavements (PCCP) to control random cracking. These joints provide a weakened plane that enables a crack to form in a controlled manner, relieving residual stresses that develop when thermal, hygral, or hydration movements are resisted by sub grade and adjoining pavement. While the concept of creating a weakened plane through saw-cutting is straightforward, determining the time and depth of the saw-cut has proven to be complicated. The goal of this project was to reduce the risk for joint raveling and random cracking. Specifically, this project has focused on: developing a procedure for determining …


High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study, Volume 1: Structural Behavior, Robert J. Frosch, Timothy S. Aldridge Dec 2008

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study, Volume 1: Structural Behavior, Robert J. Frosch, Timothy S. Aldridge

JTRP Technical Reports

Transverse cracking of concrete bridge decks is problematic in numerous states. Cracking has been identified in the negative and positive moment regions of bridges and can appear shortly after opening the structure to live loads. To improve the service life of the bridge deck as well as decrease maintenance costs, changes to current construction practices in Indiana are being considered. A typical bridge deck was instrumented which incorporated the following: increased reinforcement amounts, decreasing reinforcement spacing, and high-performance, low-shrinkage concrete. The low shrinkage concrete was achieved using a ternary concrete mix. The objective of this research was to determine the …


Flexural Behavior Of Reinforced Concrete Beams Strengthened With Cfrp Sheets And Epoxy Mortar, Byong Y. Bahn, Ronald S. Harichandran Aug 2008

Flexural Behavior Of Reinforced Concrete Beams Strengthened With Cfrp Sheets And Epoxy Mortar, Byong Y. Bahn, Ronald S. Harichandran

Civil Engineering Faculty Publications

Experiments were conducted to study the effect of using epoxy mortar patch end anchorages on the flexural behavior of reinforced concrete beams strengthened with carbon fiber-reinforced polymer (CFRP) sheets. More specifically, the effect of the end anchorage on strength, deflection, flexural strain, and interfacial shear stress was examined. The test results show that premature debonding failure of reinforced concrete beams strengthened with CFRP sheet can be delayed or prevented by using epoxy mortar patch end anchorages. A modified analytical procedure for evaluating the flexural capacity of reinforced concrete beams strengthened with CFRP sheets and epoxy mortar end anchorage is developed …


A Collection Of New Studies Using Existing And Proposed Techniques And Instrumentation For Nondestructive Testing And Analysis Of Concrete Materials And Structures, Shane D. Boone May 2008

A Collection Of New Studies Using Existing And Proposed Techniques And Instrumentation For Nondestructive Testing And Analysis Of Concrete Materials And Structures, Shane D. Boone

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A variety of studies were performed using existing and newly proposed techniques and instrumentation to further the understanding of nondestructive testing of concrete. A new combined stress wave propagation method was developed that combined the existing methods of the spectral analysis of surface waves, impact echo, and free-free resonant column experimental and analysis techniques. The method was used to determine the stiffness profile and location of embedded voids in a concrete tunnel lining modeled as a three layer concrete slab. A new equation was proposed that predicted the level of damage of concrete samples based on the functions of the …


Quality Evaluation Of Portland Cement Concrete At Early Age With Free-Free Resonant Column, Gilberto Wenglas Jan 2008

Quality Evaluation Of Portland Cement Concrete At Early Age With Free-Free Resonant Column, Gilberto Wenglas

Open Access Theses & Dissertations

At early age, the behavior and mechanical properties of portland cement concrete changes rapidly with time due to hydration. The hydration process consists of a series of chemical reactions that accelerate nonlinearly with the rise in temperature. The hydration process consists of three stages: the dormant period, the setting time, and the hardening time. Timely opening of roads and resumption of constructions depend of the knowledge of these stages. The initial and final setting times are arbitrarily determined by a standard test (ASTM C 403). Although the setting time has been studied for many decades, the new technologies allow making …


A Pilot Study On The Effects Of Temperature On The Material Properties Of Prestressed Concrete And The Use Of Thermogravimetric Analysis In The Assessment Of Heat-Affected Concrete, Kacie Caple Dec 2007

A Pilot Study On The Effects Of Temperature On The Material Properties Of Prestressed Concrete And The Use Of Thermogravimetric Analysis In The Assessment Of Heat-Affected Concrete, Kacie Caple

All Theses

An understanding of the material property changes in building materials due to exposure to a fire is needed for accurate damage assessment of a structure. Discussion pertaining to material property changes and the bond between concrete and prestressing steel following elevated temperature exposures is presented. Evaluation of the use of thermogravimetric analysis (TGA) as a post-fire analysis tool to determine the maximum temperature exposure of concrete is also included.
Heated concrete cylinders were tested to determine the compressive strength and modulus of elasticity changes of concrete. Heated steel prestressing strands were tested in tension to determine changes in the ultimate …


Use Of Recycled Tire Rubber In Concrete, Purdue Ect Team Jan 2007

Use Of Recycled Tire Rubber In Concrete, Purdue Ect Team

ECT Fact Sheets Archive

More than 250 million scrap tires weighing more than 3 million tons are generated each year in the United States. This is considered as one of the major environmental challenges facing municipalities around the world because waste rubber is not easily biodegradable even after a long period of landfill treatment. One of the solutions suggested is the use of tire rubber particles as additives in cement-based materials. Experiments under the laboratory environments commonly presented that the use of rubber in the concrete cement mix reduced drying shrinkage, brittleness, and elastic modulus, which might improve the overall durability and serviceability of …


Long-Term Effects Of Super Heavy-Weight Vehicles On Bridges, Scott M. Wood, Necip Onder Akinci, Judy Liu, Mark D. Bowman Jan 2007

Long-Term Effects Of Super Heavy-Weight Vehicles On Bridges, Scott M. Wood, Necip Onder Akinci, Judy Liu, Mark D. Bowman

JTRP Technical Reports

A permit truck which exceeds the predefined limit of 108 kips is defined as a superload in Indiana. This study was conducted to examine the long-term effects of superload trucks on the performance of typical slab-on-girder bridges and to assess the likelihood of causing immediate damage. Typical steel and prestressed concrete slab-on-girder type bridges were analyzed using both beam line analysis and detailed finite element models. Furthermore, one prestressed concrete bridge and one steel bridge were instrumented using more than 50 sensors each. Strains and deflections were measured during a live load test, and each bridge was monitored for more …


Using Coupled Eulerian And Lagrangian Grids To Model Explosive Interactions With Buildings, Braden Lusk, William P. Schonberg, Jason Baird, Robert S. Woodley, Warren Noll Nov 2006

Using Coupled Eulerian And Lagrangian Grids To Model Explosive Interactions With Buildings, Braden Lusk, William P. Schonberg, Jason Baird, Robert S. Woodley, Warren Noll

Mining Engineering Faculty Research & Creative Works

This paper presents the development of a computational model that can be used to study the interactions between structures and detonating explosives contained within them. This model was developed as part of an effort to develop a rubble characterization model for use in AmmoSIM, an agent based urban tactical decision aid (UTDA) software for weapon-target pairing. The rubble pile created following the collapse of a building in a combat situation can significantly impact mission accomplishment, particularly in the area of movement and maneuver. The information provided by AmmoSIM will enable both platoon level and command center staff to make informed …


Semiempirical Electromagnetic Modeling Of Crack Detection And Sizing In Cement-Based Materials Using Near-Field Microwave Methods, Jagadish Nadakuduti, Genda Chen, R. Zoughi Apr 2006

Semiempirical Electromagnetic Modeling Of Crack Detection And Sizing In Cement-Based Materials Using Near-Field Microwave Methods, Jagadish Nadakuduti, Genda Chen, R. Zoughi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Detection and characterization of cracks in cement-based materials is an integral part of damage evaluation for health monitoring of civil structures. Microwave signals are able to penetrate inside of dielectric materials (e.g., cement-based materials) and are sensitive to local, physical, geometrical, and dielectric variations in a structure. This makes microwave nondestructive testing and evaluation (NDT&E) techniques suitable for inspection and health monitoring of civil structures. Near-field microwave NDT&E techniques offer the added advantage of providing high spatial resolution, requiring simple hardware that may be portable, low power, fast, real time, and robust. Additionally, these techniques are noncontact and one-sided. Besides …