771.16 Penetrating Concrete Sealer - Silane: Difference between revisions

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Linseed oil treatment reduces the intrusion of water and chlorides into the deck surface on bridges with B-2, low slump, or silica fume concrete decks. The work should be performed in hot, dry weather such as in July and August.
Silane surface treatment helps to seal bridge decks by creating a hydrophobic barrier that prevents the intrusion of water and chlorides into the bridge deck. The following conditions should be considered when applying silane:


{|style="padding: 0.3em; margin-left:15px; border:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#ffddcc" width="210px" align="right"
:* Silane should be applied to concrete bridge deck surfaces. Silane should not be applied to bituminous or epoxy sealed surfaces.
|-
:* Apply prior to use of crack fillers as it can increase adhesion and provide protection to concrete.
|'''Bridge Deck, Sealer'''
:* The work should be performed with surface temperatures between 40°F and 90°F. Cooler temperatures will prevent loss of product due to evaporation, but increases cure time.  Nighttime applications are encouraged during summer applications.
|-
:* Decks should be clean and dry prior to application.  The presence of moisture will completely stop silane penetration.
|[http://library.modot.mo.gov/RDT/reports/Ri96005/Brief.htm Summary 2000]
:* Remove any loose dirt immediately prior to the application of the product.
|-
:* Apply with a low-pressure, high-volume sprayer.  Avoid application with hand pump sprayers.
|[http://library.modot.mo.gov/RDT/reports/Ri04051/or07009.pdf Report 2007]
:* Apply at a rate of 200 sq. ft./gal. When applying product, be careful not to get overspray on vehicles. Allow product to penetrate the bridge deck and dry prior to opening to traffic.
|-
 
|'''See also:''' [http://www.modot.gov/services/OR/byDate.htm Innovation Library]
Silane should be applied on all new concrete bridge decks. If additional cracking occurs, reapplication should be considered in the first 3 years. Additional applications are recommended at 7- to 10-year intervals.
|}


==Materials==
==Materials==
Boiled linseed oil, mineral spirits and sand.
'''General Note''': The linseed oil penetrates the fine pores in the deck and greatly reduces the permeability/porosity of the deck. This provides freeze/thaw protection and reduces the chloride penetration into the deck. The linseed oil treatment is a total surface treatment, not a crack treatment. Newly constructed bridges receive the first application of linseed oil by the contractor upon completion. Maintenance personnel apply a second treatment about one year later. It has been shown that additional treatment after the second coat offer little additional benefit as only a small amount of the linseed oil penetrates the surface. Bridges several years old that show signs of scaling may benefit from an additional application of linseed oil. '''Should not be applied to worn or polished bridge decks.'''
Bridges to receive an application of linseed oil are identified by GHQ and district bridge inspection personnel. A list is created from which material quantities can be determined. Linseed oil and mineral spirits are ordered on a statewide purchase.
==Procedures==
1. The deck should be completely clean and dry. Any loose dirt or dust should be blown off the deck immediately prior to the application of the mixture.
2. The material is applied using a sprayer or a distributor that has been thoroughly cleaned out. See table below for the proper application rate. The mixture is applied to half the deck at a time. The inside face and top of the barrier curbs shall also be treated. Traffic must be stopped while the material is being applied to prevent over spray on vehicles.
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
|-
!style="background:#BEBEBE"|Deck Surface Concrete||style="background:#BEBEBE"|Application Rate
|-
| Silica Fume || 0.02 gal/yd<sup>2</sup>
|-
| B-2 || 0.03 gal/yd<sup>2</sup>
|-
| Low Slump || 0.02 gal/yd<sup>2</sup>
|-
|colspan="2" style="background:#999933"|'''Mixture is 50% linseed oil and 50% mineral spirits.'''
|}
3. Traffic must not be allowed on the wetted, slippery surface. The mixture is allowed to penetrate and dry. Areas that dry quickly should be sprayed with the hand sprayer to maintain an even coat. Puddles should be squeegeed to assist drying. Drying time is dependent on application rate, temperature, sunshine, humidity, and wind. Apply sand to surface to improve short-term skid resistance.
4. Traffic is allowed on the treated surface only when the surface is dry and traffic does not pick up the linseed oil.
5. Repeat treatment to the other half of the deck.


6. Excess sand shall be removed when the deck is completely dry.
Silane should be applied according to manufacturer’s recommendations. See Sec 1053.10 for specification.


==Safety==
==Health, Environment and Guidance==
The mineral spirits and linseed oil mixture has a low flash point. Care must be exercised to prevent igniting the mixture by sparks, open flame or other means. In no case should the mixture be heated in a distributor. Spray must be controlled so not to get on passing vehicles or adjacent property.


==Instructional Photographs==
Work crews should wear appropriate [[:Category:132 Safety#Personal Protective Equipment (PPE)|PPE]] and follow manufacturer’s recommendations when applying. Runoff from crack sealing needs to be controlled to prevent contamination of waterways and property damage. Refer to MSDS additional information.  See [[:Category:170 Maintenance Activity Planning Guidelines#R322 Bridge Preventative Maintenance|R322 Bridge Seal Coats Maintenance Planning Guidelines]] for additional information.
{|
|[[Image:771.18 Linseed Oil Treatment1.jpg|400px]] || [[Image:771.18 Linseed Oil Treatment2.jpg|400px]]
|-
|'''The material is applied using a distributor that has been thoroughly cleaned out. Many districts have created distributors.''' || '''Traffic must be stopped while the material is being applied to prevent over spray on vehicles.'''
|-
|[[Image:771.18 Linseed Oil Treatment3.jpg|400px]] || [[Image:771.18 Linseed Oil Treatment4.jpg|400px]]
|-
|'''The mixture is applied to half the deck at a time.''' || '''Apply sand to surface to improve short term skid resistance.'''
|}


[[Category:771 Bridge Preventative Maintenance Guidelines|771.18]]
[[Category:771 Bridge Preventive Maintenance Guidelines|771.16]]

Latest revision as of 08:53, 22 November 2016

Code: R322

Silane surface treatment helps to seal bridge decks by creating a hydrophobic barrier that prevents the intrusion of water and chlorides into the bridge deck. The following conditions should be considered when applying silane:

  • Silane should be applied to concrete bridge deck surfaces. Silane should not be applied to bituminous or epoxy sealed surfaces.
  • Apply prior to use of crack fillers as it can increase adhesion and provide protection to concrete.
  • The work should be performed with surface temperatures between 40°F and 90°F. Cooler temperatures will prevent loss of product due to evaporation, but increases cure time. Nighttime applications are encouraged during summer applications.
  • Decks should be clean and dry prior to application. The presence of moisture will completely stop silane penetration.
  • Remove any loose dirt immediately prior to the application of the product.
  • Apply with a low-pressure, high-volume sprayer. Avoid application with hand pump sprayers.
  • Apply at a rate of 200 sq. ft./gal. When applying product, be careful not to get overspray on vehicles. Allow product to penetrate the bridge deck and dry prior to opening to traffic.

Silane should be applied on all new concrete bridge decks. If additional cracking occurs, reapplication should be considered in the first 3 years. Additional applications are recommended at 7- to 10-year intervals.

Materials

Silane should be applied according to manufacturer’s recommendations. See Sec 1053.10 for specification.

Health, Environment and Guidance

Work crews should wear appropriate PPE and follow manufacturer’s recommendations when applying. Runoff from crack sealing needs to be controlled to prevent contamination of waterways and property damage. Refer to MSDS additional information. See R322 Bridge Seal Coats Maintenance Planning Guidelines for additional information.

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