Category:774 Cathodic Protection - Revision history

Smithk: Inclusive language

2021-06-07T20:23:52Z

Inclusive language

← Older revision		Revision as of 15:23, 7 June 2021
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	==774.5 Field Data Records==		==774.5 Field Data Records==
	===774.5.1 Procedure===		===774.5.1 Procedure===
	~~The field~~ data ~~collector~~ should have at ~~his~~ disposal a complete set of design drawings for the cathodic protection system.		Field data collectors should have at their disposal a complete set of design drawings for the cathodic protection system.

	The Cathodic Protection Record consists of three sections. At the top left of the form is various structure identification information. ''At the top right of the form are: Section A, the Routine Cathodic System Evaluation, and Section B, the Four Hour Depolarization Evaluation.'' It is desirable that the routine evaluation be performed monthly for the first year of operation and then every two months thereafter. The four hour depolarization evaluation shall be performed annually in the spring. Upon completion a copy of only the Spring evaluation forms (with sections A and B filled out) shall be forwarded to the Maintenance Division by June 1, each year. The following describes the procedures for completing the form.		The Cathodic Protection Record consists of three sections. At the top left of the form is various structure identification information. ''At the top right of the form are: Section A, the Routine Cathodic System Evaluation, and Section B, the Four Hour Depolarization Evaluation.'' It is desirable that the routine evaluation be performed monthly for the first year of operation and then every two months thereafter. The four hour depolarization evaluation shall be performed annually in the spring. Upon completion a copy of only the Spring evaluation forms (with sections A and B filled out) shall be forwarded to the Maintenance Division by June 1, each year. The following describes the procedures for completing the form.

Smithk at 20:18, 18 August 2020

2020-08-18T20:18:46Z

← Older revision		Revision as of 15:18, 18 August 2020
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	\|[http://library.modot.mo.gov/RDT/reports/Ri04030/or11013.pdf Experimental Galvanic Anode for Cathodic Protection of Bridge A12112, 2011]		\|[http://library.modot.mo.gov/RDT/reports/Ri04030/or11013.pdf Experimental Galvanic Anode for Cathodic Protection of Bridge A12112, 2011]
	\|-		\|-
	\|'''See also:''' [~~http~~://www.modot.~~gov~~/~~services/OR/byDate.htm Innovation Library~~]		\|'''See also:''' [https://www.modot.org/research-publications Research Publications]
	\|}		\|}

Smithk: Per BR, deck rehabilitation guidance has been updated to current methods.

2020-02-04T17:17:55Z

Per BR, deck rehabilitation guidance has been updated to current methods.

EPGsysop: /* 774.1.3 Design Guidelines */

2017-04-07T19:41:12Z

774.1.3 Design Guidelines

← Older revision		Revision as of 14:41, 7 April 2017
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	3. The rectifier shall be sized such as to limit the maximum sustained current at the effective surface of contact area between the anode and the concrete to below 10 mA per square foot (107.6 mA/m<sup>2</sup>) for an anode type mesh system.		3. The rectifier shall be sized such as to limit the maximum sustained current at the effective surface of contact area between the anode and the concrete to below 10 mA per square foot (107.6 mA/m<sup>2</sup>) for an anode type mesh system.

	4. For anode mesh system installations, the contractor shall provide computations ~~such~~ that the anode voltage drop (IR) shall not exceed 300 mV from the power feed to the furthest point from the power feed.		4. For anode mesh system installations, the contractor shall provide computations so that the anode voltage drop (IR) shall not exceed 300 mV from the power feed to the furthest point from the power feed.

	5. Anodes in any system type are to be placed no closer than 3 in. to slab drains or expansion device armor.		5. Anodes in any system type are to be placed no closer than 3 in. to slab drains or expansion device armor.

Smithk: /* 774.5.2 Routine Cathodic System Evaluation: Section A */ updated link

2016-07-22T13:27:57Z

774.5.2 Routine Cathodic System Evaluation: Section A: updated link

← Older revision		Revision as of 08:27, 22 July 2016
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	:'''Input Voltage''' (volts) is the DC voltage for each zone measured to the nearest 0.1 volts.		:'''Input Voltage''' (volts) is the DC voltage for each zone measured to the nearest 0.1 volts.

	:'''Input Current''' (Amps) is the current to each zone read from either the external hand held or built in meter. These readings should fall between the ''upper and lower current parameters'' established in the '''Fixed Design Parameter Table'''. If the input current does not fall between the limits, see [[#774.6 Trouble-Shooting Checklist\|Trouble-Shooting Checklist]].		:'''Input Current''' (Amps) is the current to each zone read from either the external hand held or built in meter. These readings should fall between the ''upper and lower current parameters'' established in the '''Fixed Design Parameter Table'''. If the input current does not fall between the limits, see [[#774.6 Trouble Shooting Checklist\|Trouble Shooting Checklist]].

	:'''Input Current Density''' (milliAmps/sq. ft.) is equal to the Input Current (Amps) divided by the zone size (ft<sup>2</sup>) multiplied by 1000.		:'''Input Current Density''' (milliAmps/sq. ft.) is equal to the Input Current (Amps) divided by the zone size (ft<sup>2</sup>) multiplied by 1000.
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	<u>'''Reference Cell and Probe Readings'''</u>		<u>'''Reference Cell and Probe Readings'''</u>

	:'''On Potential''' (millivolts) is a reference cell voltage reading, for each zone, taken with the system on using either the external hand held or built in meter. Electrically connect the reinforcing steel (system ground) to the positive terminal of the voltmeter and the reference cell lead to the negative (ground) terminal of the voltmeter. Note, these readings will be negative, example, -365 millivolts. Compare each zone reading with the lower and upper potential parameters from Reference Cell Parameter Table. If the reading is not in the given range, see Trouble-Shooting Section 6.		:'''On Potential''' (millivolts) is a reference cell voltage reading, for each zone, taken with the system on using either the external hand held or built in meter. Electrically connect the reinforcing steel (system ground) to the positive terminal of the voltmeter and the reference cell lead to the negative (ground) terminal of the voltmeter. Note, these readings will be negative, example, -365 millivolts. Compare each zone reading with the lower and upper potential parameters from Reference Cell Parameter Table. If the reading is not in the given range, see Trouble Shooting Section 6.

	:'''Instant Off Potential''' (millivolts) is the reading taken immediately after the protective current is turned off. This reading should be taken from about 100 to 1000 msec after shutting off the current. Measuring the potential incorrectly could lead to significant error. (See alternate procedure below).		:'''Instant Off Potential''' (millivolts) is the reading taken immediately after the protective current is turned off. This reading should be taken from about 100 to 1000 msec after shutting off the current. Measuring the potential incorrectly could lead to significant error. (See alternate procedure below).

Smithk: Per Bridge, updated link to Cathodic System Evaluation form

2011-11-23T14:51:34Z

Per Bridge, updated link to Cathodic System Evaluation form

← Older revision		Revision as of 09:51, 23 November 2011
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	\|'''Figures'''		\|'''Figures'''
	\|-		\|-
	\|[~~[media~~:~~774 Cathodic System Evaluation~~.~~docx \|~~Example Blank Cathodic System Evaluation Form]]		\|[http://ghepg01/forms/BR/774_Cathodic_System_Evaluation.dotx Example Blank Cathodic System Evaluation Form]
	\|-		\|-
	\|[[Media:774 Cathodic System Evaluation Example1.docx\|Cathodic System Evaluation Example 1]]		\|[[Media:774 Cathodic System Evaluation Example1.docx\|Cathodic System Evaluation Example 1]]
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	:'''Alternate Procedure for Obtaining Instant Off Potential''' (millivolts). The Back EMF (BEMF) reading is the potential generated by the polarization of the anode and the cathode. This voltage has to be overcome by the rectifier before it can force current through the cathodic protection system. BEMF is measured across the rectifier output terminals. The positive lead of the multimeter is connected to the positive output terminal of the rectifier and the negative lead is connected to the negative terminal of the output waveform. A multi-meter such as a Fluke 87 can be used for the purpose. The minimum reading should be measured using a 1 millisecond window. On the filtered rectifiers, the current must be interrupted to make the measurement.		:'''Alternate Procedure for Obtaining Instant Off Potential''' (millivolts). The Back EMF (BEMF) reading is the potential generated by the polarization of the anode and the cathode. This voltage has to be overcome by the rectifier before it can force current through the cathodic protection system. BEMF is measured across the rectifier output terminals. The positive lead of the multimeter is connected to the positive output terminal of the rectifier and the negative lead is connected to the negative terminal of the output waveform. A multi-meter such as a Fluke 87 can be used for the purpose. The minimum reading should be measured using a 1 millisecond window. On the filtered rectifiers, the current must be interrupted to make the measurement.

	<center>[~~[media~~:~~774 Cathodic System Evaluation~~.~~docx \|~~Example Blank Cathodic System Evaluation Form]]</center>		<center>[http://ghepg01/forms/BR/774_Cathodic_System_Evaluation.dotx Example Blank Cathodic System Evaluation Form]</center>

	===774.5.3 Four Hour Depolarization Evaluation: Section B===		===774.5.3 Four Hour Depolarization Evaluation: Section B===

Smithk: /* 774.5.2 Routine Cathodic System Evaluation: Section A */ clarification

2011-11-22T14:17:43Z

774.5.2 Routine Cathodic System Evaluation: Section A: clarification

← Older revision		Revision as of 09:17, 22 November 2011
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	:'''On Potential''' (millivolts) is a reference cell voltage reading, for each zone, taken with the system on using either the external hand held or built in meter. Electrically connect the reinforcing steel (system ground) to the positive terminal of the voltmeter and the reference cell lead to the negative (ground) terminal of the voltmeter. Note, these readings will be negative, example, -365 millivolts. Compare each zone reading with the lower and upper potential parameters from Reference Cell Parameter Table. If the reading is not in the given range, see Trouble-Shooting Section 6.		:'''On Potential''' (millivolts) is a reference cell voltage reading, for each zone, taken with the system on using either the external hand held or built in meter. Electrically connect the reinforcing steel (system ground) to the positive terminal of the voltmeter and the reference cell lead to the negative (ground) terminal of the voltmeter. Note, these readings will be negative, example, -365 millivolts. Compare each zone reading with the lower and upper potential parameters from Reference Cell Parameter Table. If the reading is not in the given range, see Trouble-Shooting Section 6.

	:'''Instant Off Potential''' (millivolts) is the reading taken immediately after the protective current is turned off. This reading should be taken from about 100 to 1000 msec after shutting off the current . Measuring the potential incorrectly could lead to significant error. (~~see~~ alternate procedure below).		:'''Instant Off Potential''' (millivolts) is the reading taken immediately after the protective current is turned off. This reading should be taken from about 100 to 1000 msec after shutting off the current. Measuring the potential incorrectly could lead to significant error. (See alternate procedure below).

	:'''Probe Reading''' (+ or –) This reading is a voltage polarity which indicates the direction of current flow. This is accomplished by connecting the positive lead of a voltmeter to the probe and the negative lead to the system negative (reinforcing steel). The probe is connected to the reinforcing steel through a 10 Ohm shunt resistor. A negative (–) reading indicates that the reinforcing steel is corroding. A positive (+) reading indicates that the reinforcing steel is protected. Note: A number value is not needed, only the polarity of (+) or (–) is to be recorded.		:'''Probe Reading''' (+ or –) This reading is a voltage polarity which indicates the direction of current flow. This is accomplished by connecting the positive lead of a voltmeter to the probe and the negative lead to the system negative (reinforcing steel). The probe is connected to the reinforcing steel through a 10 Ohm shunt resistor. A negative (–) reading indicates that the reinforcing steel is corroding. A positive (+) reading indicates that the reinforcing steel is protected. Note: A number value is not needed, only the polarity of (+) or (–) is to be recorded.

Smithk: updated link

2011-11-22T14:15:58Z

updated link

← Older revision		Revision as of 09:15, 22 November 2011
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	:'''Alternate Procedure for Obtaining Instant Off Potential''' (millivolts). The Back EMF (BEMF) reading is the potential generated by the polarization of the anode and the cathode. This voltage has to be overcome by the rectifier before it can force current through the cathodic protection system. BEMF is measured across the rectifier output terminals. The positive lead of the multimeter is connected to the positive output terminal of the rectifier and the negative lead is connected to the negative terminal of the output waveform. A multi-meter such as a Fluke 87 can be used for the purpose. The minimum reading should be measured using a 1 millisecond window. On the filtered rectifiers, the current must be interrupted to make the measurement.		:'''Alternate Procedure for Obtaining Instant Off Potential''' (millivolts). The Back EMF (BEMF) reading is the potential generated by the polarization of the anode and the cathode. This voltage has to be overcome by the rectifier before it can force current through the cathodic protection system. BEMF is measured across the rectifier output terminals. The positive lead of the multimeter is connected to the positive output terminal of the rectifier and the negative lead is connected to the negative terminal of the output waveform. A multi-meter such as a Fluke 87 can be used for the purpose. The minimum reading should be measured using a 1 millisecond window. On the filtered rectifiers, the current must be interrupted to make the measurement.

	<center>[[media:774 Cathodic System Evaluation ~~Blank~~.~~doc~~ \|Example Blank Cathodic System Evaluation Form]]</center>		<center>[[media:774 Cathodic System Evaluation.docx \|Example Blank Cathodic System Evaluation Form]]</center>

	===774.5.3 Four Hour Depolarization Evaluation: Section B===		===774.5.3 Four Hour Depolarization Evaluation: Section B===

Smithk: Per Bridge, updated outdated material. Revised forms for better clarity.

2011-11-22T14:12:20Z

Per Bridge, updated outdated material. Revised forms for better clarity.

Show changes

Smithk: Per Organizational Results, links to reports added

2011-03-08T14:12:23Z

Per Organizational Results, links to reports added

← Older revision		Revision as of 09:12, 8 March 2011
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	==774.1 Definition, Policy and Design Guidelines==		==774.1 Definition, Policy and Design Guidelines==
	===774.1.1 Definition===		===774.1.1 Definition===
			{\|style="padding: 0.3em; margin-left:15px; border:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#ffddcc" width="210px" align="right"
			\|-
			\|'''Galvanic Cathodic Protection'''
			\|-
			\|[http://library.modot.mo.gov/RDT/reports/Ri04030/or11013.pdf Experimental Galvanic Anode for Cathodic Protection of Bridge A12112, 2011]
			\|-
			\|'''See also:''' [http://www.modot.gov/services/OR/byDate.htm Innovation Library]
			\|}

	'''Cathodic Protection''' in bridge decks is defined as: the reduction or elimination of corrosion by making the reinforcing steel a cathode by means of an impressed DC current.		'''Cathodic Protection''' in bridge decks is defined as: the reduction or elimination of corrosion by making the reinforcing steel a cathode by means of an impressed DC current.

← Older revision		Revision as of 12:17, 4 February 2020
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	'''<u>Type 3 (Mesh)</u>'''		'''<u>Type 3 (Mesh)</u>'''

	This system consist of a conductive netting or mesh (anode) placed on top of the deck, divided into separate zones and then the deck overlaid. See ~~section on overlay~~ for specific types.		This system consist of a conductive netting or mesh (anode) placed on top of the deck, divided into separate zones and then the deck overlaid. See [[#774.3 Wearing Surfaces\|EPG 774.3 Wearing Surfaces]] for specific types.

	:'''Raychem System''' - There are no Raychem systems working and haven’t been for more than 10 years.		:'''Raychem System''' - There are no Raychem systems working and haven’t been for more than 10 years.
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	:(There are a few bridges with the platinum anode still conducting current around the zones circumference, but all the primary carbon strand anodes have burned up and shorted out. These systems are protecting an insignificant portion of the surface area of the bridge and should be turned off. The District can save a little on electric bills and can keep the rectifiers in case they can be used elsewhere or for parts.)		:(There are a few bridges with the platinum anode still conducting current around the zones circumference, but all the primary carbon strand anodes have burned up and shorted out. These systems are protecting an insignificant portion of the surface area of the bridge and should be turned off. The District can save a little on electric bills and can keep the rectifiers in case they can be used elsewhere or for parts.)

	==774.3 ~~Overlays~~==		==774.3 Wearing Surfaces==
	Five types of ~~overlays~~ have been used on Missouri bridges with cathodic protection systems.		Five types of wearing surfaces have been used on Missouri bridges with cathodic protection systems.

	<u>'''Asphaltic Concrete'''</u>		<u>'''Asphaltic Concrete'''</u>

	Was used in a 2 1/4 in. thick layer on the early coke breeze systems and in a 1 1/2 in. layer on some early slotted systems (Asphaltic ~~overlays~~ were not used after January 1986, but have had new surface courses added on some and systems and ~~overlays~~ are still performing).		Was used in a 2 1/4 in. thick layer on the early coke breeze systems and in a 1 1/2 in. layer on some early slotted systems (Asphaltic wearing surfaces were not used after January 1986, but have had new surface courses added on some and systems and wearing surfaces are still performing).

	<u>'''Latex Modified Concrete, Low Slump Concrete, Silica Fume Concrete'''</u>		<u>'''Latex Modified Concrete, Low Slump Concrete, Silica Fume Concrete'''</u>

	These ~~overlays~~ were used on slotted and mesh systems. Silica Fume, used on only one cathodic system deck, is not recommended for use on cathodic protected bridges, therefore no future use on cathodically protected bridges is planned.		These wearing surfaces were used on slotted and mesh systems. Silica Fume, used on only one cathodic system deck, is not recommended for use on cathodic protected bridges, therefore no future use on cathodically protected bridges is planned.

	<u>'''Gemcrete Thin Overlay'''</u>		<u>'''Gemcrete Thin Overlay'''</u>

	(Gemcrete ~~overlay~~ is no longer available and the only bridge deck remaining with it is being rehabilitated in 2006.)		(Gemcrete wearing surface is no longer available and the only bridge deck remaining with it is being rehabilitated in 2006.)

	==774.4 Maintenance Procedures==		==774.4 Maintenance Procedures==
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	<u>'''Deck Repair'''</u>		<u>'''Deck Repair'''</u>

	Contact must be made with the district office before ~~overlay~~ and/or deck repairs are done on a cathodically protected bridge. Repairs to the wearing surface should have no adverse effect on the cathodic protection system. Anodes shall be inspected and an electrical continuity test performed on the effected area. When repairing the wearing surface, the debonded area shall be saw cut 1 in. plus or minus. The material in the area shall be removed by lightweight air or electrical hammer and chisel or point. If anodes or supply wires are damaged, they shall be repaired. The appropriate splice kit and procedure shall be used, see anode repair. If sound concrete is removed to allow room for a splice, remove by chipping. In addition, see the following notes for different type systems.		Contact must be made with the district office before wearing surface and/or deck repairs are done on a cathodically protected bridge. Repairs to the wearing surface should have no adverse effect on the cathodic protection system. Anodes shall be inspected and an electrical continuity test performed on the effected area. When repairing the wearing surface, the debonded area shall be saw cut 1 in. plus or minus. The material in the area shall be removed by lightweight air or electrical hammer and chisel or point. If anodes or supply wires are damaged, they shall be repaired. The appropriate splice kit and procedure shall be used, see anode repair. If sound concrete is removed to allow room for a splice, remove by chipping. In addition, see the following notes for different type systems.

	:'''Slotted Systems (Type 2)''' - All slots should be inspected and an electrical continuity test performed on the affected area.		:'''Slotted Systems (Type 2)''' - All slots should be inspected and an electrical continuity test performed on the affected area.