| Author |
Message |
Russ Hinkle, AIA, CDT, LEED BD+C
Senior Member
Username: rhinkle
Post Number: 141
Registered: 02-2006
| | Posted on Tuesday, September 13, 2016 - 08:09 am: |    |
We have an installation with colored concrete paving (vehicle traffic and sidewalks) and colored concrete decorative walls. There is a lot of discussion about applying a sealer and the potential VOC's (it is for a healthcare client). The colors are dark grays. Some have said we need this to prevent fading. I am concerned about the long term maintenance as I don't believe the owner will recoat yearly as most of the products recommend. I am of the opinion a siloxine is the best, applied once. Or do nothing. It is in Michigan (so salt is a concern) but we have incorporated a snowmelt system to help reduce the need for salt and plows.
Russ Hinkle |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 1013
Registered: 12-2006
| | Posted on Tuesday, September 13, 2016 - 08:56 am: | |
First, please make sure that the gray color isn't achieved using carbon black. It will fade rather quickly and it's doubtful that the owner wants a maintenance item.
If the desire is for a one-time application you're probably better off avoiding silanes and siloxanes as they require recoating every few years and are only advised for use on vertical surfaces.
Consider looking at a good quality, topically applied silicate, probably sodium as the other options (magnesium, potassium, etc.) are even more expensive but may be preferable for exterior applications, especially at freeze-thaw conditions. I prefer Sinak's products out of San Diego since it's in solution, not suspension, but there are dozens of suspension products out there that should be okay. Check with the manufacturers to make sure that your slip-resistance isn't compromised. |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 211
Registered: 10-2003
| | Posted on Tuesday, September 13, 2016 - 09:01 am: | |
Mineral Oxide pigments in integrally colored concrete do not fade. The surface will change appearance, however, due to erosion of cement paste exposing aggregates. The pigment producers offer sealers with pigments to deepen the color and create more uniform appearance, but the sealers do wear as you state.
See my article in Construction Specifier at http://19233-presscdn.pagely.netdna-cdn.com/wp-content/uploads/2016/08/DC618.pdf.
Michael Chusid, RA FCSI CCS
www.chusid.com www.buildingproduct.guru 818-219-4937 |
John Bunzick, CCS, CCCA, LEED AP
Senior Member
Username: bunzick
Post Number: 1694
Registered: 03-2002
| | Posted on Tuesday, September 13, 2016 - 04:35 pm: | |
It seems unlikely to me that any sort of sealer or water repellent would affect whether the color will fade. As Michael points out, there will be some erosion of the cement paste, but I don't see how a sealer would stop that process very much, especially on a horizontal surface. You may actually be creating more of a maintenance issue by applying something that has to be maintained, rather than leaving it be. As to VOC, applied to the exterior and allowed to off-gas sufficiently, I would be surprised if there was any greater problem than paint. |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 1015
Registered: 12-2006
| | Posted on Tuesday, September 13, 2016 - 05:33 pm: | |
Eliminating wear and reapplication are two benefits of using silicates; they penetrate into the concrete and chemically react with the matrix to densify the concrete. Essentially, they are as close to permanent and non-maintenance as anything I know of in that part of the industry.
I agree with Michael that mineral oxides are the way to go for pigments. Carbon black based products provide a less expensive means and are often submitted to 'cut costs'. I would avoid them. Mineral oxides should also permit the use of penetrants like silicates. From what I have found, many pigment manufacturers offer silicate options or accept their use. |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 212
Registered: 10-2003
| | Posted on Tuesday, September 13, 2016 - 05:42 pm: | |
you can reduce surface erosion with hardeners like silicates or by the addition of pozzolans. As an alternative to silicates, consider a colloidal silica treatment such as http://lythic.net/. It works as well, yet is much easier to apply and has fewer environmental problems.
My article in Construction Specifier is a few years old, but may be helpful: http://lythic.net/website042011/wp-content/uploads/2011/05/Article-2009.03-ConstructionSpecificer_MakingSenseofDensifiers.pdf
Michael Chusid, RA FCSI CCS
www.chusid.com www.buildingproduct.guru 818-219-4937 |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 213
Registered: 10-2003
| | Posted on Friday, September 16, 2016 - 02:31 pm: | |
Building on Ken's comment about avoiding carbon black --
In addition cost considerations, carbon black provides a richer, darker black than can be achieved with mineral oxide pigments. Carbon black, however, can leach out of portland cement concrete that is exposed to repeated cycle of wet and dry and does not have a sealer. Carbon black should work satisfactorily in most interior applications with a sealer.
Carbon black is used exteriorally, however. It is are used, for example, at many gas stations. The criteria there are different than the typical "architectural" project. Portland cement concrete is used around pump islands because it is less effected by spills and easier to clean in comparison to asphaltic concrete. The concrete is pigmented to make stains, spills, drips and tire makes less visible than they would be on uncolored concrete, and to harmonize the appearance of the portland cement concrete with the surrounding asphaltic concrete.
A reminder: Water curing will lighten integrally colored concrete, so write a tight spec.
Michael Chusid, RA FCSI CCS
www.chusid.com www.buildingproduct.guru 818-219-4937 |
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