413.1 Micro-Surfacing - Revision history

Legged1: /* 413.1.2.3 Surface Preparation */ terminology

2024-03-06T21:51:48Z

413.1.2.3 Surface Preparation: terminology

← Older revision		Revision as of 16:51, 6 March 2024
Line 56:		Line 56:
	Existing cracks wider than ¼-inch should be crack filled prior to the application of the micro-surface. Crack filling should be measured and added as a separate bid item in accordance with Sec 413.70 for bituminous surfaces or Sec 413.80 for Portland cement concrete surfaces.		Existing cracks wider than ¼-inch should be crack filled prior to the application of the micro-surface. Crack filling should be measured and added as a separate bid item in accordance with Sec 413.70 for bituminous surfaces or Sec 413.80 for Portland cement concrete surfaces.

	If numerous cracks exist and the pavement is in good condition, then it is more economical to place a surface treatment instead of crack filling prior to the micro-surface. A ~~chip~~ seal or a scrub seal treatment should be considered as a pre-treatment to the micro-surface to seal existing cracks and fill in minor surface irregularities prior to the micro-surface.		If numerous cracks exist and the pavement is in good condition, then it is more economical to place a surface treatment instead of crack filling prior to the micro-surface. A seal coat or a scrub seal treatment should be considered as a pre-treatment to the micro-surface to seal existing cracks and fill in minor surface irregularities prior to the micro-surface.

	When a pre-treatment is conducted (e.g., crack sealing, ~~chip~~ seal, etc.) it is imperative that the pre-treatment be completely cured to allow for any water evaporation within the material. A minimum of two weeks is required by the standard specification; however, this curing period will depend on the product type and environmental conditions. The curing period may need to be extended during cooler weather for some pre-treatments with visible signs of the pre-treatment not setting up under traffic. Likewise, if a two pass micro-surface is being placed, the first pass needs a minimum of 24 hours of traffic for compaction and curing to allow excess water to evaporate before the second micro-surfacing lift is placed.		When a pre-treatment is conducted (e.g., crack sealing, seal coat, etc.) it is imperative that the pre-treatment be completely cured to allow for any water evaporation within the material. A minimum of two weeks is required by the standard specification; however, this curing period will depend on the product type and environmental conditions. The curing period may need to be extended during cooler weather for some pre-treatments with visible signs of the pre-treatment not setting up under traffic. Likewise, if a two pass micro-surface is being placed, the first pass needs a minimum of 24 hours of traffic for compaction and curing to allow excess water to evaporate before the second micro-surfacing lift is placed.

	Generally, existing durable and painted pavement marking lines (4”, 6”, 8”), may remain in place and covered with a micro-surfacing treatment if the existing marking itself is well bonded to the pavement. However, existing durable intersection pavement markings (stop lines, arrows, words, symbols, etc.) shall be removed in accordance with Sec 620.50 and shall be paid separately.		Generally, existing durable and painted pavement marking lines (4”, 6”, 8”), may remain in place and covered with a micro-surfacing treatment if the existing marking itself is well bonded to the pavement. However, existing durable intersection pavement markings (stop lines, arrows, words, symbols, etc.) shall be removed in accordance with Sec 620.50 and shall be paid separately.

Smithk: Per CM, guidance for single pass and double pass micro-surfacing was expanded; guidance for micro-surfacing grade selection and surface preparation also expanded. New guidance for post construction and the method of measurement and basis of payment now available.

2020-05-07T14:26:35Z

Per CM, guidance for single pass and double pass micro-surfacing was expanded; guidance for micro-surfacing grade selection and surface preparation also expanded. New guidance for post construction and the method of measurement and basis of payment now available.

Show changes

EPGsysop at 17:56, 25 May 2018

2018-05-25T17:56:33Z

← Older revision		Revision as of 12:56, 25 May 2018
Line 1:		Line 1:
	==413.1 Description==		==413.1.1 Description==
	Micro-surfacing is a slurry seal that uses a polymer-modified emulsion binder, a high quality dense graded aggregate, mineral filler, water and other additives, properly proportioned, mixed and spread on a paved surface. The filler can be Portland cement, hydrated lime or other approved materials. A self-propelled continuous loading machine or a truck-mounted machine is used to proportion and mix the material and apply the mixture to the pavement surface.		Micro-surfacing is a slurry seal that uses a polymer-modified emulsion binder, a high quality dense graded aggregate, mineral filler, water and other additives, properly proportioned, mixed and spread on a paved surface. The filler can be Portland cement, hydrated lime or other approved materials. A self-propelled continuous loading machine or a truck-mounted machine is used to proportion and mix the material and apply the mixture to the pavement surface.

Line 8:		Line 8:
	Micro-surfacing is applied using a slurry/screed operation. It may be used to fill ruts, one at a time, or, for shallower rutting, it may be used with a "scratch" coat, just filling the low or shallow points to restore the cross slope. There is some consolidation as the water leaves, thus deeper applications should be done in multiple layers with a time interval in between applications.		Micro-surfacing is applied using a slurry/screed operation. It may be used to fill ruts, one at a time, or, for shallower rutting, it may be used with a "scratch" coat, just filling the low or shallow points to restore the cross slope. There is some consolidation as the water leaves, thus deeper applications should be done in multiple layers with a time interval in between applications.

	==413.2 Use in Contracts==		==413.1.2 Use in Contracts==
	A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=7 Sec 413.10] in the Standard Specification.		A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=7 Sec 413.10] in the Standard Specification.

Line 15:		Line 15:
	When micro-surfacing is applied over any type of existing striping, the material can release from the old pavement marking in a few months. This can cause confusion as well as make for an unsightly appearance. Contracts for micro-surfacing should include removal of the existing striping before micro-surfacing.		When micro-surfacing is applied over any type of existing striping, the material can release from the old pavement marking in a few months. This can cause confusion as well as make for an unsightly appearance. Contracts for micro-surfacing should include removal of the existing striping before micro-surfacing.

	==413.3 Materials Inspection==		==413.1.3 Materials Inspection==

	===413.3.1 Scope===		===413.1.3.1 Scope===
	To establish procedures for mix design, inspection and acceptance of materials used in Micro-Surfacing. Aggregate for use in surface treatments shall be inspected in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. Asphalt Binder for use in surface treatments shall be inspected in accordance with [[:Category:1015 Bituminous Material\|EPG 1015 Bituminous Material]].		To establish procedures for mix design, inspection and acceptance of materials used in Micro-Surfacing. Aggregate for use in surface treatments shall be inspected in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. Asphalt Binder for use in surface treatments shall be inspected in accordance with [[:Category:1015 Bituminous Material\|EPG 1015 Bituminous Material]].

	===413.3.2 Mix Design Procedure===		===413.1.3.2 Mix Design Procedure===
	In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=7 Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.		In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=7 Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.

Line 47:		Line 47:
	:f. For verification, a trial may be prepared and submitted to the Laboratory.		:f. For verification, a trial may be prepared and submitted to the Laboratory.

	===413.3.3 Report===		===413.1.3.3 Report===

	A letter of transmittal will accompany the approved mixture to the District Construction and Materials Engineer with distribution as follows:		A letter of transmittal will accompany the approved mixture to the District Construction and Materials Engineer with distribution as follows:
Line 68:		Line 68:
	A copy of the approved formula accompanied by a letter of transmittal from the District Construction and Materials Engineer is to be forwarded to the contractor.		A copy of the approved formula accompanied by a letter of transmittal from the District Construction and Materials Engineer is to be forwarded to the contractor.

	==413.4 Laboratory Procedure==		==413.1.4 Laboratory Procedure==
	Micro-Surfacing mix properties shall be determined, when required, in accordance with the applicable International Slurry Surfacing Association (ISSA) Technical Bulletins.		Micro-Surfacing mix properties shall be determined, when required, in accordance with the applicable International Slurry Surfacing Association (ISSA) Technical Bulletins.

	[[Category:413 Surface Treatments and Preventive Maintenance\|413.01]]		[[Category:413 Surface Treatments and Preventive Maintenance\|413.01]]

Smithk: updated links

2016-06-09T14:10:13Z

updated links

← Older revision		Revision as of 09:10, 9 June 2016
Line 9:		Line 9:

	==413.2 Use in Contracts==		==413.2 Use in Contracts==
	A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://modot.~~mo.gov~~/business/standards_and_specs/~~Sec0413~~.pdf Sec 413.10] in the Standard Specification.		A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=7 Sec 413.10] in the Standard Specification.

	Type IIIR should be specified for filling deeper ruts (>1/2 in.) or for raising shoulders. Type IIIR is applied with a narrow screed box, with no limit on the quantity used per square yard. Type II is a light, one-pass application and should be used to correct minor surface irregularities. For this application, it is only recommended for light traffic (<3500 AADT) routes with no rutting. Type III is a thicker application and should be specified for heavier traffic routes. Two passes are required to place Type III. The first pass is used to fill shallower ruts (<1/2 in.), and the final pass completes the coverage. Type II or III might be used in conjunction with Type IIIR applications.		Type IIIR should be specified for filling deeper ruts (>1/2 in.) or for raising shoulders. Type IIIR is applied with a narrow screed box, with no limit on the quantity used per square yard. Type II is a light, one-pass application and should be used to correct minor surface irregularities. For this application, it is only recommended for light traffic (<3500 AADT) routes with no rutting. Type III is a thicker application and should be specified for heavier traffic routes. Two passes are required to place Type III. The first pass is used to fill shallower ruts (<1/2 in.), and the final pass completes the coverage. Type II or III might be used in conjunction with Type IIIR applications.
Line 21:		Line 21:

	===413.3.2 Mix Design Procedure===		===413.3.2 Mix Design Procedure===
	In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://modot.~~mo.gov~~/business/standards_and_specs/~~Sec0413~~.pdf Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.		In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=7 Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.

	<div id="District Procedure">		<div id="District Procedure">

Smithk: minor clarification

2010-11-24T17:03:02Z

minor clarification

← Older revision		Revision as of 12:03, 24 November 2010
Line 11:		Line 11:
	A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://modot.mo.gov/business/standards_and_specs/Sec0413.pdf Sec 413.10] in the Standard Specification.		A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://modot.mo.gov/business/standards_and_specs/Sec0413.pdf Sec 413.10] in the Standard Specification.

	Type IIIR should be specified for filling deeper ruts (>1/2 in.) or for raising shoulders. Type IIIR is applied with a narrow screed box, with no limit on the quantity used per square yard. Type II is a light, one-pass application and should be used to correct minor surface irregularities. For this application, it is only recommended for light traffic (<3500 ~~ADT~~) routes with no rutting. Type III is a thicker application and should be specified for heavier traffic routes. Two passes are required to place Type III. The first pass is used to fill shallower ruts (<1/2 in.), and the final pass completes the coverage. Type II or III might be used in conjunction with Type IIIR applications.		Type IIIR should be specified for filling deeper ruts (>1/2 in.) or for raising shoulders. Type IIIR is applied with a narrow screed box, with no limit on the quantity used per square yard. Type II is a light, one-pass application and should be used to correct minor surface irregularities. For this application, it is only recommended for light traffic (<3500 AADT) routes with no rutting. Type III is a thicker application and should be specified for heavier traffic routes. Two passes are required to place Type III. The first pass is used to fill shallower ruts (<1/2 in.), and the final pass completes the coverage. Type II or III might be used in conjunction with Type IIIR applications.

	When micro-surfacing is applied over any type of existing striping, the material can release from the old pavement marking in a few months. This can cause confusion as well as make for an unsightly appearance. Contracts for micro-surfacing should include removal of the existing striping before micro-surfacing.		When micro-surfacing is applied over any type of existing striping, the material can release from the old pavement marking in a few months. This can cause confusion as well as make for an unsightly appearance. Contracts for micro-surfacing should include removal of the existing striping before micro-surfacing.
Line 32:		Line 32:
	:Letting Date		:Letting Date
	:Proposed Work – Job Location and Length		:Proposed Work – Job Location and Length
	:Average Daily Traffic (~~ADT~~)		:Annual Average Daily Traffic (AADT)
	:Mix Use – Mainline, Shoulders, Outer Roads, etc.		:Mix Use – Mainline, Shoulders, Outer Roads, etc.
	:Quantity of Mix		:Quantity of Mix

Smithk: /* 413.3.2 Mix Design Procedure */ minor clarification

2010-04-02T19:27:39Z

413.3.2 Mix Design Procedure: minor clarification

← Older revision		Revision as of 14:27, 2 April 2010
Line 26:		Line 26:
	'''District Procedure'''		'''District Procedure'''

	When the district receives a proposed trial mix formula, as required by the Standard Specifications, the mixture properties, components and proportions should be checked to ensure compliance with Specifications and that they are approved for the intended use. It may be necessary for the district to advise the contractor to make changes in the proposed mixture in order to comply with Department policies. A QC plan in accordance with [[:Category:1001 General Requirements for Material\|1001 General Requirements for Material]] covering each aggregate fraction should be on file in the district office or received with the JMF. The target gradations shown on the QC plan and JMF must match. When the district is satisfied that the proposed mixture is acceptable, a copy of the JMF and the contractor's letter shall be submitted to the Materials Field Office, accompanied by a letter of transmittal with comments, any corrections made and recommendations. The transmittal letter shall contain the following information:		When the district receives a proposed trial mix formula, as required by the Standard Specifications, the mixture properties, components and proportions should be checked to ensure compliance with Specifications and that they are approved for the intended use. It may be necessary for the district to advise the contractor to make changes in the proposed mixture in order to comply with Department policies. A QC plan in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]] covering each aggregate fraction should be on file in the district office or received with the JMF. The target gradations shown on the QC plan and JMF must match. When the district is satisfied that the proposed mixture is acceptable, a copy of the JMF and the contractor's letter shall be submitted to the Materials Field Office, accompanied by a letter of transmittal with comments, any corrections made and recommendations. The transmittal letter shall contain the following information:
	:Project information – Job Number, Route, County, Contract Number.		:Project information – Job Number, Route, County, Contract Number.
	:Mixture Type		:Mixture Type
Line 45:		Line 45:
	:d. Gradations of the aggregates are checked for specification compliance.		:d. Gradations of the aggregates are checked for specification compliance.
	:e. All calculations on the proposed JMF are checked.		:e. All calculations on the proposed JMF are checked.
	:f. For verification, a trial may be prepared and submitted to the Laboratory.		:f. For verification, a trial may be prepared and submitted to the Laboratory.

	===413.3.3 Report===		===413.3.3 Report===

Smithk: minor clarifications to differentiate EPG articles (that are referenced as "articles", not "sections") from specifications (that are referenced as "sections")

2010-04-02T19:27:21Z

minor clarifications to differentiate EPG articles (that are referenced as "articles", not "sections") from specifications (that are referenced as "sections")

← Older revision		Revision as of 14:27, 2 April 2010
Line 18:		Line 18:

	===413.3.1 Scope===		===413.3.1 Scope===
	To establish procedures for mix design, inspection and acceptance of materials used in Micro-Surfacing. Aggregate for use in surface treatments shall be inspected in accordance with [[:Category:1001 General Requirements for Material\|1001 General Requirements for Material]]. Asphalt Binder for use in surface treatments shall be inspected in accordance with [[:Category:1015 Bituminous Material\|1015 Bituminous Material]].		To establish procedures for mix design, inspection and acceptance of materials used in Micro-Surfacing. Aggregate for use in surface treatments shall be inspected in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. Asphalt Binder for use in surface treatments shall be inspected in accordance with [[:Category:1015 Bituminous Material\|EPG 1015 Bituminous Material]].

	===413.3.2 Mix Design Procedure===		===413.3.2 Mix Design Procedure===
	In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://modot.mo.gov/business/standards_and_specs/Sec0413.pdf Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material\|1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.		In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://modot.mo.gov/business/standards_and_specs/Sec0413.pdf Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material\|EPG 1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.

	<div id="District Procedure">		<div id="District Procedure">

Smithk: updated Operations Engineer title to Construction and Materials Engineer

2009-12-28T17:23:03Z

updated Operations Engineer title to Construction and Materials Engineer

← Older revision		Revision as of 12:23, 28 December 2009
Line 26:		Line 26:
	'''District Procedure'''		'''District Procedure'''

	When the ~~District~~ receives a proposed trial mix formula, as required by the Standard Specifications, the mixture properties, components and proportions should be checked to ensure compliance with Specifications and that they are approved for the intended use. It may be necessary for the ~~District~~ to advise the contractor to make changes in the proposed mixture in order to comply with Department policies. A QC plan in accordance with [[:Category:1001 General Requirements for Material\|1001 General Requirements for Material]] covering each aggregate fraction should be on file in the ~~District Office~~ or received with the JMF. The target gradations shown on the QC plan and JMF must match. When the ~~District~~ is satisfied that the proposed mixture is acceptable, a copy of the JMF and the contractor's letter shall be submitted to the Materials Field Office, accompanied by a letter of transmittal with comments, any corrections made and recommendations. The transmittal letter shall contain the following information:		When the district receives a proposed trial mix formula, as required by the Standard Specifications, the mixture properties, components and proportions should be checked to ensure compliance with Specifications and that they are approved for the intended use. It may be necessary for the district to advise the contractor to make changes in the proposed mixture in order to comply with Department policies. A QC plan in accordance with [[:Category:1001 General Requirements for Material\|1001 General Requirements for Material]] covering each aggregate fraction should be on file in the district office or received with the JMF. The target gradations shown on the QC plan and JMF must match. When the district is satisfied that the proposed mixture is acceptable, a copy of the JMF and the contractor's letter shall be submitted to the Materials Field Office, accompanied by a letter of transmittal with comments, any corrections made and recommendations. The transmittal letter shall contain the following information:
	:Project information – Job Number, Route, County, Contract Number.		:Project information – Job Number, Route, County, Contract Number.
	:Mixture Type		:Mixture Type
Line 49:		Line 49:
	===413.3.3 Report===		===413.3.3 Report===

	A letter of transmittal will accompany the approved mixture to the ~~district Operations~~ Engineer with distribution as follows:		A letter of transmittal will accompany the approved mixture to the District Construction and Materials Engineer with distribution as follows:

	{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"		{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"
Line 55:		Line 55:
	!style="background:#BEBEBE"\|Title\|\|style="background:#BEBEBE"\|Copy of Transmittal Letter and Approved Mix		!style="background:#BEBEBE"\|Title\|\|style="background:#BEBEBE"\|Copy of Transmittal Letter and Approved Mix
	\|-		\|-
	\| District ~~Operations~~ Engineer \|\| 1		\| District Construction and Materials Engineer \|\| 1
	\|-		\|-
	\|Project Operations Clerk\|\| 1		\|Project Operations Clerk\|\| 1
Line 66:		Line 66:
	The letter of transmittal and the approved mixture will be sent by electronic mail to the individuals listed above.		The letter of transmittal and the approved mixture will be sent by electronic mail to the individuals listed above.

	A copy of the approved formula accompanied by a letter of transmittal from the District ~~Operations~~ Engineer is to be forwarded to the contractor.		A copy of the approved formula accompanied by a letter of transmittal from the District Construction and Materials Engineer is to be forwarded to the contractor.

	==413.4 Laboratory Procedure==		==413.4 Laboratory Procedure==

EPG-Admin at 18:57, 28 November 2007

2007-11-28T18:57:24Z

New page

==413.1 Description==
Micro-surfacing is a slurry seal that uses a polymer-modified emulsion binder, a high quality dense graded aggregate, mineral filler, water and other additives, properly proportioned, mixed and spread on a paved surface. The filler can be Portland cement, hydrated lime or other approved materials. A self-propelled continuous loading machine or a truck-mounted machine is used to proportion and mix the material and apply the mixture to the pavement surface.

Micro-surfacing is used to retard raveling and oxidation of the pavement, fill non-plastic ruts, reduce the intrusion of water, improve surface friction, and remove minor surface irregularities. After placement, the water "breaks" and evaporates, leaving a hard asphalt/cement/aggregate mixture that is resistant to further compaction or movement. Because the aggregates required to make such a mixture are hard and angular, the mixture has good friction properties, and can also be used to improve surface friction conditions. It should not be used primarily for sealing surfaces, due to the rigidity of the mixture.

Micro-surfacing is not a structural layer and will not bridge any distress. It only fills depressions and will not stop further rutting. It does not contain rejuvenators, but hard asphalt, which will not rejuvenate an oxidized surface. It does not fill or seal cracks. Existing cracks will reflect through the micro-surfacing within a few months.

Micro-surfacing is applied using a slurry/screed operation. It may be used to fill ruts, one at a time, or, for shallower rutting, it may be used with a "scratch" coat, just filling the low or shallow points to restore the cross slope. There is some consolidation as the water leaves, thus deeper applications should be done in multiple layers with a time interval in between applications.

==413.2 Use in Contracts==
A single course micro-surfacing can be used to retard oxidation and light to moderate raveling, improve skid resistance to a structurally sound pavement. A multiple course micro-surfacing is used to correct other minor pavement surface deficiencies, including moderate rutting due to consolidation rather than plastic flow of the mix. Due to the brittle nature of the micro-surfacing is a poor crack sealer. Surface preparation for a micro-surfacing should include the sealing or filling of the cracks. Refer to [http://modot.mo.gov/business/standards_and_specs/Sec0413.pdf Sec 413.10] in the Standard Specification.

Type IIIR should be specified for filling deeper ruts (>1/2 in.) or for raising shoulders. Type IIIR is applied with a narrow screed box, with no limit on the quantity used per square yard. Type II is a light, one-pass application and should be used to correct minor surface irregularities. For this application, it is only recommended for light traffic (<3500 ADT) routes with no rutting. Type III is a thicker application and should be specified for heavier traffic routes. Two passes are required to place Type III. The first pass is used to fill shallower ruts (<1/2 in.), and the final pass completes the coverage. Type II or III might be used in conjunction with Type IIIR applications.

When micro-surfacing is applied over any type of existing striping, the material can release from the old pavement marking in a few months. This can cause confusion as well as make for an unsightly appearance. Contracts for micro-surfacing should include removal of the existing striping before micro-surfacing.

==413.3 Materials Inspection==

===413.3.1 Scope===
To establish procedures for mix design, inspection and acceptance of materials used in Micro-Surfacing. Aggregate for use in surface treatments shall be inspected in accordance with [[:Category:1001 General Requirements for Material|1001 General Requirements for Material]]. Asphalt Binder for use in surface treatments shall be inspected in accordance with [[:Category:1015 Bituminous Material|1015 Bituminous Material]].

===413.3.2 Mix Design Procedure===
In order for a micro-surfacing mix formula to be approved, the contractor’s proposed job mix formula (JMF) shall be submitted as required in [http://modot.mo.gov/business/standards_and_specs/Sec0413.pdf Standard Specification Sec 413.10.3]. Trial mix samples will not be required unless requested by the Field Office. If requested, the samples are to be obtained and submitted to the Central Laboratory in accordance with [[:Category:1001 General Requirements for Material|1001 General Requirements for Material]]. When possible, the JMF and correspondence should be transmitted electronically. The Materials Field Office e-mail address is MFO.

<div id="District Procedure">
'''District Procedure'''

When the District receives a proposed trial mix formula, as required by the Standard Specifications, the mixture properties, components and proportions should be checked to ensure compliance with Specifications and that they are approved for the intended use. It may be necessary for the District to advise the contractor to make changes in the proposed mixture in order to comply with Department policies. A QC plan in accordance with [[:Category:1001 General Requirements for Material|1001 General Requirements for Material]] covering each aggregate fraction should be on file in the District Office or received with the JMF. The target gradations shown on the QC plan and JMF must match. When the District is satisfied that the proposed mixture is acceptable, a copy of the JMF and the contractor's letter shall be submitted to the Materials Field Office, accompanied by a letter of transmittal with comments, any corrections made and recommendations. The transmittal letter shall contain the following information:
:Project information – Job Number, Route, County, Contract Number.
:Mixture Type
:Grade and Source of Asphalt Binder
:Letting Date
:Proposed Work – Job Location and Length
:Average Daily Traffic (ADT)
:Mix Use – Mainline, Shoulders, Outer Roads, etc.
:Quantity of Mix

'''Field Office Procedure'''

The Materials Field Office is charged with the responsibility of processing the mix formula. General procedures for processing a micro-surfacing mix formula are as follows:

:a. A letter from a District requesting a mix with a copy of the contractor's JMF and letter is received.
:b. Contract specifications for the project are checked for necessary items.
:c. Grade of asphalt as well as the refinery to be used and the percent asphalt recommended are reviewed.
:d. Gradations of the aggregates are checked for specification compliance.
:e. All calculations on the proposed JMF are checked.
:f. For verification, a trial may be prepared and submitted to the Laboratory.

===413.3.3 Report===

A letter of transmittal will accompany the approved mixture to the district Operations Engineer with distribution as follows:

{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
|-
!style="background:#BEBEBE"|Title||style="background:#BEBEBE"|Copy of Transmittal Letter and Approved Mix
|-
| District Operations Engineer || 1
|-
|Project Operations Clerk|| 1
|-
|Resident Engineer|| 1
|-
|Field Office File|| 1
|}

The letter of transmittal and the approved mixture will be sent by electronic mail to the individuals listed above.

A copy of the approved formula accompanied by a letter of transmittal from the District Operations Engineer is to be forwarded to the contractor.

==413.4 Laboratory Procedure==
Micro-Surfacing mix properties shall be determined, when required, in accordance with the applicable International Slurry Surfacing Association (ISSA) Technical Bulletins.

[[Category:413 Surface Treatments and Preventive Maintenance|413.01]]