_ap_ufes{"success":true,"siteUrl":"projectchampionz.com.ng","urls":{"Home":"https://projectchampionz.com.ng","Category":"https://projectchampionz.com.ng/projecttopics/about-project-championz/","Archive":"https://projectchampionz.com.ng/2022/05/","Post":"https://projectchampionz.com.ng/2022/05/17/human-factors-as-determinants-of-marine-accidents-in-maritime-companies-in-nigeria/","Page":"https://projectchampionz.com.ng/pathology-project-topics-and-materials/","Attachment":"https://projectchampionz.com.ng/2022/04/27/does-making-money-online-require-software-tools/ppp2/","Nav_menu_item":"https://projectchampionz.com.ng/2021/10/10/93928/","Custom_css":"https://projectchampionz.com.ng/2019/10/18/proc-2/","Oembed_cache":"https://projectchampionz.com.ng/2020/08/09/010e02649ccd61f4b1233b15599ed153/","Wp_global_styles":"https://projectchampionz.com.ng/2022/04/06/wp-global-styles-proc/","Amp_validated_url":"https://projectchampionz.com.ng/amp_validated_url/15a6906a18bf1e2723b7d6bb7c1a58c0/","Buttons-x":"https://projectchampionz.com.ng/buttons-x/flat-info-2/","Acf-field-group":"https://projectchampionz.com.ng/?post_type=acf-field-group&p=56510","Acf-field":"https://projectchampionz.com.ng/?post_type=acf-field&p=56514","Wpcf7_contact_form":"https://projectchampionz.com.ng/?post_type=wpcf7_contact_form&p=2077","Rpt_pricing_table":"https://projectchampionz.com.ng/rpt_pricing_table/price-list-1/","Wp_automatic":"https://projectchampionz.com.ng/wp_automatic/iproject/","Is_search_form":"https://projectchampionz.com.ng/?post_type=is_search_form&p=70552"}}_ap_ufee VIABILITY OF EMBEDDED ULTRASONIC SENSORS FOR STRUCTURAL HEALTH MONITORING OF CONCRETE CRACKINGING OF CONCRETE CRACKING - Project Topics for Student

VIABILITY OF EMBEDDED ULTRASONIC SENSORS FOR STRUCTURAL HEALTH MONITORING OF CONCRETE CRACKINGING OF CONCRETE CRACKING

  • : Ms Word Format
  • : 70 Pages
  • : ₦3000
  • : 1-5 Chapters
  •  
  • Click to DOWNLOAD Materials

VIABILITY OF EMBEDDED ULTRASONIC SENSORS FOR STRUCTURAL HEALTH MONITORING OF CONCRETE CRACKING

ABSTRACT

Concrete infrastructure is an integral part of a transportation system. Concrete is used in many bridges and a large percent of the U.S. highway system. Determining the condition of the concrete bridges and pavements is essential for proper maintenance of these structures. The current system for determining maintenance in the US is based on maintenance time schedules or on condition surveys performed at varying intervals. Recent developments with sensors and sensing systems could allow more frequent and even real-time monitoring of the concrete structures to determine structural health.

 

Through the use of Structural Health Monitoring (SHM) concepts and ultrasonic embedded sensors, a system was constructed that is capable of detecting cracking in a standard ASTM C78 concrete beam specimen. The system consisted of a pulser/receiver and ultrasonic sensors. Two types of piezoelectric ultrasonic sensors were constructed and embedded in concrete beam specimens which were subjected to cracking. The first sensor was constructed using radially activated disc piezoelectric elements and the second sensor was constructed from bender, or bimorph, piezoelectric elements.

 

Following construction of the specimens determining the detection capability of the system required the creation of cracking in the beam specimens. Idealized laboratory cracking was created by saw-cutting the beam specimens in a regular pattern and analyzing the resulting ultrasonic signals. The same procedure was then used with controlled loading to detect real cracks in a beam specimen.

 

 

The resulting signal data from testing was analyzed by using a power ratio calculation which related a baseline signal power calculation to power calculated at varying times during curing, and different stages of testing. The power ratio calculation combined with the SHM test procedure and the embedded ultrasonic sensors was able to detect the sawcut crack, and the real crack created in the concrete beam specimens.

 

TABLE OF CONTENTS

LIST OF FIGURES ……………………………………………………………………………………….. vii

LIST OF TABLES …………………………………………………………………………………………. x

ACKNOWLEDGEMENTS …………………………………………………………………………….. xi

Chapter 1 Background/Problem Statement ………………………………………………………… 1

Objectives of the Research ……………………………………………………………………….. 4

Chapter 2 Literature Review ……………………………………………………………………………. 5

Ultrasonics ……………………………………………………………………………………………… 5

Structural Health Monitoring …………………………………………………………………….. 8Example SHM System ………………………………………………………………………. 10

Portland Cement Concrete ………………………………………………………………………… 12

Ultrasonics and SHM in Portland Cement Concrete …………………………………….. 15

Effect of Varying Mixture Proportions ………………………………………………… 15

Crack Characterization using Rayleigh Waves ……………………………………… 20

Embedded Sensors in Concrete …………………………………………………………… 22

Chapter 3 Experimental Methods …………………………………………………………………….. 25

Ultrasonics ……………………………………………………………………………………………… 25

Radially-Activated Disc Elements ………………………………………………………. 26

Bender Elements ……………………………………………………………………………….. 27

Disc Sensor Construction …………………………………………………………………… 31

Bender Sensor Construction ……………………………………………………………….. 31

Structural Health Monitoring ……………………………………………………………… 33

Concrete Specimens ………………………………………………………………………….. 34

Specimen Size Selection …………………………………………………………………….. 34

Concrete Materials …………………………………………………………………………….. 36

Construction and Sensor Installation ……………………………………………………. 39

Structural Health Monitoring  Setup …………………………………………………………… 46

Saw-cut Test Setup ………………………………………………………………………………….. 48

Controlled Cracking Test Setup…………………………………………………………………. 53

Chapter 4 Analysis and Results ……………………………………………………………………….. 60

Structural Health Monitoring Data …………………………………………………………….. 60

Saw-cut Testing Data ……………………………………………………………………………….. 66

Controlled Cracking Data …………………………………………………………………………. 71Chapter 5 Conclusions and Recommendations …………………………………………………… 81Conclusions…………………………………………………………………………………………….. 81

Recommendations ……………………………………………………………………………………. 83

Appendix A: SHM Data Graphs ………………………………………………………………………. 85

Appendix B: Saw-cutting Data Graphs……………………………………………………………… 144

Appendix C: Crack Testing Data Graphs ………………………………………………………….. 250

References …………………………………………………………………………………………………….. 265

Chapter 1 

 

Background/Problem Statement

Transportation infrastructure is a key component for any country and an especially important component of the United States (US) economy. Nearly all of the goods sold in the US have traveled along one part of the US’s transportation infrastructure network.

While 83.5 percent of all US highways were paved using exclusively asphalt concrete in

2008, 5.5 percent were paved using exclusively portland cement concrete (USDOT 2009), and the remainder were paved with a combination of asphalt and portland cement concrete.  However, when considering only interstate highways, 26.5 percent were paved using exclusively portland cement concrete and 44.4 percent were paved using exclusively asphalt concrete, with the remainder a combination of the two types. Interstates are used to transport goods from one local system to the next, and are exposed to higher truck traffic and more damage. It is thus critical to maintain these lynchpins in the US transportation infrastructure to ensure the effective transport of goods across the

US.

 

In order to maintain the concrete pavement infrastructure in the US, inspections are performed at various time intervals based on the condition of the pavement. The inspections provide an overview of the condition of the pavement at particular points in time, and thus allow pavement managers to outline the degradation of the pavement and plan maintenance or repair activities. However, the inspections are only single points of data and leave large periods of time for which there is no indication of the current condition of the pavement. A new strategy, known as Structural Health Monitoring

(SHM), can provide real time monitoring of a pavement structure. Through the use of SHM concepts and novel sensor systems in pavement and other transportation infrastructure, the ability to understand the current condition of a pavement at all times is an achievable reality.

 

While SHM systems are being developed for bridge infrastructure in limited test cases (Bergeron 2011 and Knapshaefer 2012), systems for pavement are not yet applied to field sections. The lack of SHM in pavements is linked more with the length of paving sections and cost than with true technical development. Developing a low cost sensor and SHM system would allow the use of SHM in pavement applications. To simplify some of the technology transfer, a pavement slab is considered comparable to a concrete bridge deck with no reinforcing steel. Thus, advancements in bridge SHM should provide some guidance for use with pavement slabs. To extend bridge deck SHM to the pavement field, the importance of sensor system selection becomes increasingly more important due to the increased size and broad distribution of the pavement. SHM sensor systems generally target a specific component of a bridge by measuring a fundamental condition of the structure. Two examples are the use of corrosion sensors and accelerometers. A corrosion sensor can be used on steel strands to ensure that capacity is not lost, thus threatening the carrying capacity of the bridge. Accelerometers are used to determine the vibrations of a bridge deck to analyze the movement of the bridge and determine any increased stress from high winds or heavy traffic. Each piece of a bridge could one day be subjected to

3

continuous monitoring using a multitude of sensors providing real time condition to bridge owners.

 

The critical failure mode of concrete slabs is through cracking. As cracking frequency or severity increases, the slab provides less serviceability to traffic and lower stiffness to the overall pavement structure. The ability to detect and eventually characterize these cracks could provide early warning of crack propagation and allow for early repair or maintenance to ensure a high level of serviceability.

 

A sensor technology that has shown increasing promise when trying to identify cracking in concrete is the use of ultrasonic sensors. Ultrasonic technology has been applied for many years to determine the condition of concrete using ASTM C597, the pulse velocity method. Another use has been in foundations through the use of ASTM D6760 and crosshole testing methods. Both methods provide an opportunity to determine the condition of the concrete structure, but are limited to a single point in time and may only cover specific locations in the concrete structure. Additional methods using surface wave analysis have been able to determine crack depths in concrete given access to the cracked side of the concrete. Surface wave analysis would be limited for bridges and pavements to areas with access and would be subjected to the environmental elements and traffic present on infrastructure in the US. If an ultrasonic sensor system could be protected from the environment and traffic, as well as provide constant monitoring of the concrete structure for cracking or other properties, the system could be vital in an SHM system targeted at monitoring concrete pavement or bridge decks.

Objectives of the Research

The main objective of this research is to contribute to the development of an ultrasonic sensor system capable of detecting cracking in concrete slabs that could be integrated into a structural health monitoring system on portland cement concrete pavements or bridges with concrete decks. In order to achieve the longer-term objective, several smaller objectives were set for this thesis research that would determine the potential to create an ultrasonic sensor system.

 

  1. Locate or construct ultrasonic sensors capable of surviving the harsh environment present in a concrete system while providing sufficiently long sensing distances over time when used within a pseudo SHM framework
  2. Determine the capability of the ultrasonic sensor systems to detect an idealized crack created using concrete sawing techniques.
  3. Determine the capability of the ultrasonic sensor systems to detect laboratoryinduced cracking by monitoring the system during controlled crack testing.

VIABILITY OF EMBEDDED ULTRASONIC SENSORS FOR STRUCTURAL HEALTH MONITORING OF CONCRETE CRACKING

Sharing is caring!

Leave a Reply