new concrete

[Barry Loy]

I recently did some concrete work for a new home owner. Washing off mud mostly and construction debris. I am wondering if his new concrete was mixed with too much sand. Not being a concrete contactor I am not sure of this. His new drive way, sidewalks and patios looked real nice BUT, it seemed to me as I was washing all this for him that some of the 'grit' washed off as well. Also, when using my surface cleaner, it seemed to be 'etching' just removing more than I am accustomed to seeing. I stopped using the surface cleaner and continued by using only my wand ( made for a longer job and much sorer hands ). Anyone have any experience such as this ?
Thanks,
Barry Loy

 

[Mark]

Sounds like maybe the concrete was still a little green.

This customer may be a good candidate for a concrete sealer.

 

[Glenn]

Barry,
How long ago was the concrete poured?
Glenn

 

[Steven Rowlett]

Barry, New concrete needs to cure for 30 days before sealing.

 

[Rick - Pro Wash]

We are finding a lot of new concrete like this lately. I spoke with one of the Transit Mix officials about it. He explained that many concrete contractors are putting too much water in the product at the site just before it is poured. It makes it a lot easier to finish the surface and cuts down on labor costs.
The problem shows up after the contractor is long gone. Soft surface, weak and easily cracked final product.

A sealer may be the ticket for this problem, or will the sealer fail because of the faulty concrete and then soil your reputation also?

See ya,
Rick

 

[ron]

sealing

the comment about waiting 30 days to seal is incorrect if you want really strong cement and the best seal. The sealer should be put IN THE CEMENT. pUTTING v-seal INTO THE CEMENT ACT. WILL INCREASE THE PSI RATEING[BY A WHOLE LOT] and prevent salt damage and keeps oil from getting in so deep you cant get it out.
There are contractors that dont agitate the surface of new cement to the point of bringing the CREAM to the top[to do it right you need a power vibrator]-just enuff to make it look good and go. After 3-4 cleanings you'll start to see the stone[its black]. Then the customer will blame you. Home owners wont see this happen for a long time because they dont power wash all the time but ive seen lots of fast food places with the tops worn off.

 

[Glenn]

Steve is right in his post as he uses an acrylic surface sealer applied with a roller. The V-seal is a penetrating sealer usually sprayed on. I think both of you are right, just talking about 2 different things. Believe me, Steve knows about sealers.
Glenn

 

[Steven Rowlett]

Thanks Glenn, Aggregate concrete needs to cure for 30 days before sealing. White concrete (brushed or troweled) can be sealed after the water has dissipated WITH a CURE & SEAL product.
The aggregate sealer is pure acrylic (30% solids) and the cure & seal also a pure acrylic but with 25% solids. These are two different products and the 30% WILL seal in moisture if applied in less than 30 days.

 

[Dan Flynn]

Hey rick,

I have seen a tone of it too. Over the last few years. Both residential and commercial. I figured maybe it was to cold when they poured it.

Good to know what's happening.

Thanks

 

[Bill B]

Steven, Gregg, et. al. Your comments are very interesting. I am in the middle of trying to determine which type of sealant / curative to use in which application. Silanes, polysiloxanes, acrylics, other hybrids - gets fairly confusing. Could you send me to a site where I might get a primer on this subject? My main concern is sealing 3-5 year old driveways and sidewalks - about half aggregate, half broom brushed. Vendors all believe their product is best for all applications, so I need something more objective. Any help appreciated.

 

[Steven Rowlet]

Bill, Try the following websites.
worldofconcrete.com
concrete.com
concretesoup.com
ncma.org
We have excellent results with acrylics on the surfaces you describe, hopefully the websites listed will help you. There are many factors in concrete. The enviroment the concrete is subject to is different across the country, cold, heat, rain, snow, ect. Perhaps this will help you. Let me know if I can help you further.
Steven

 

[Roger]

On the subject of new concrete, has anyone had a problem like this? Today I was cleaning a new garage floor(drywall mud, paint, etc) for a builder, which was poured about 2 1/2 months ago. When it was poured and they ran the skimmer on it, there were leaves on it. The leaves got pushed just under the surface and covered with a very thin layer of concrete. From the start you could only see 2 or 3 of them barely showing, as I starting washing, more and more started showing up . The water was knocking off the thin layer of concrete and washing the leaf out. When that started happening I stopped using the pressure washer. Starting using a wire brush to knock the drywall mud spots loose. Even the brush it would occasionally pull up a leaf. I called the builder and told him what was happening and he said "just do the best you can". When it came time to rinse I didnt want to use pressure so I started rinsing with a garden hose spray nozzle, they were still comming up everywhere. Now there are leaf imprints scattered all over the floor. Of course this was my first job for this builder and wanted it to look good, so I could get more work from him. He hasn't seen it yet, so dont know his reaction will be. Murphy's Law in Action i guess.

Also, anyone know what will remove Red chalkline chalk? Looks like someone was filling their chalkline box and spilled it everywhere.