Sunday, 3 February 2019

Delamination (spalling) and Surface Peeling of Driveway Surfaces in a Freeze Thaw and Vapor Lock and other Additives vs. Topical Sealers or "No" Sealers for Concrete



Vapor Lock or Sealer and why?

The most common dictionary definition of "spalling" concrete:



spalled concrete is caused by poor finishing and the use of water on the surface to aid in the finishing process. Excess water and over-finishing create a weak surface that can't handle freeze-thaw expansion and contraction. This definition is widely advertised everywhere that is not a northern freeze thaw climate. Everyone can be an expert on the internet, and what might be true in California, may not be true in Canada, and especially in harsh climates of the Prairie Provinces.

In my reality we see similar examples of spalling that can be directly related to freeze thaw, salt use, vehicle salts, and most recently in our city the use of Magnesium Chloride in conjunction with road salts and sand. This is also compounded by the inclusion of "light weight aggregates" by the concrete plants in the concrete mix. (these cause pop-outs during freeze thaw cycles) The costs associated with importing gravel from other provinces and jurisdictions is expensive.

Through experience and in an effort to maintain happy customers (minimize issues with concrete) we have advocated the following recommendations:
  • never push wet salty vehicle sludge and water out of your garage and onto your driveway.
  • if you have a downspout running through an area you park on your driveway in the winter try and redirect that flow of water. installing drainage in walks is common now.
  • keep your driveway shovelled and clean, dry is good thing!
  • wash and reseal with topical acrylic sealer in the spring to protect annually. 

The latest defence in the toolbox that we tried in 2018 is Vapor Lock Additive. All the above recommendations still apply with the exception of the Acrylic Sealer or even better in conjunction with the use of Acrylic Sealer. The cost of  Acrylic Sealer can be from .50 - $1.00 per square foot depending on the person doing the installation, the number of coats of sealer and the quality of the sealer. By choosing Vapor Lock, you are saving this sealer cost over the future years. 

There are a few customers that do not worry about pop-outs, spalling concrete, and opt out of using any additives. 


What is Vapor Lock Additive:

First Vapor Lock costs .75 cents per square foot of concrete or about $750 for an average driveway. This cost is passed on to the customer. The benefit, one time cost for customers. (reducing the cost over the life of the concrete) Typically we would only offer Vapor Lock with plain broom finish concrete with no colour additives or where there is no intent to use a "Topical" sealer to enhance the colouration of the concrete. Typically Stamped Concrete, Exposed Aggregate Concrete and Coloured Broom are used with Acylic Sealer (not vapor lock) to enhance the colour.

Does Vapor Lock work?

Rockscapes Concrete Saskatoon  have been offering concrete installations and have a strong history of offering excellent product in the Saskatoon and area. We have advocated annual washing and sealing of concrete with Acrylic's with great success! Vapor Lock is knew to us, we feel the obligation to offer to our customers every alternative to make informed decisions. The decision to purchase a driveway is a difficult and expensive decision. Concrete Contractors do not use the same methods or systems. By creating a template of how we do driveways that is available upon request, and offering the options we do, we have a long track record of successful installations. Approx. 30% of our customers opted for Vapor Lock in 2018, and I had personally inspected some driveways that were done as test sites in 2017 or earlier. I feel that Vapor Lock should be considered for most outside plain concrete applications. Anything that can reduce pop-outs, spalling, and extend the life of your concrete should be considered. (In my opinion) I look forward to seeing the success of the driveways we used Vapor Lock on in 2018, without the use of Acrylics, and sharing some addresses with prospective customers.

DESCRIPTION
Vapor LockTM 20/21 Waterproofing & Exterior Protection Concrete Ad-mixture is a ready to use concrete admixture that has an inorganic chemical reaction with components of the cement and utilizes the water of convenience to eliminate the route of water ingress/egress. This reaction is a permanent and integral component of the finished concrete.
BASIC USES
Vapor LockTM 20/21 water proofs/densify concrete to an industry lead- ing level. Vapor LockTM 20/21 should be added to concrete whenever superior water proofing, extended service life, chemical resistance and densification at an economical cost are desired.
MAJOR ADVANTAGES OF Vapor LockTM 20/21
~Water proofs concrete (.0017 US Perms) ~Increases concrete density and hardness ~Increased abrasion resistance
~Requires no Chemical Curing

~Stops ACR, ASR ~Effective in reducing:
-Plastic & Drying Shrinkage Cracking -Efflorescence
-Freeze-thaw spalling -Delamination
-Slab curl





Friday, 1 April 2016

How to wash and seal / maintain concrete driveways in freeze thaw climate....

Wash and Sealing of Concrete By Rockscapes Concrete Service

This is a guideline for the restoration and maintenance of concrete. In Saskatoon’s freeze thaw climate, it is particularly important to do proper annual maintenance in order to minimize damage and prolong the life of your concrete. These are some of the techniques that have produced successful results for Rockscapes; we have performed thousands of concrete driveways and / or concrete projects in Saskatoon and area. Other contractors may have different techniques.



Once applied some sealers are virtually impossible to remove.

1)     One of the most useful tips I can offer in our freeze thaw climate is to try to keep your concrete clean (shoveled) and dry during the winter season to keep salty, slushy snow to a minimum, never push salty vehicle salt water from garage and out the door onto your driveway. Especially important with north facing shaded driveways.
2)     Be careful of some of the products out there that say they won’t damage concrete and will melt ice. Sometimes just sprinkling a little clean sand will give that temporary short-term protection required.
3)     Don’t use ice chippers, they will mark or chip your concrete.

WASH THE CONCRETE WITH A PRESSURE WASHER TO RID IT OF MOLD, DIRT, SALT, CRACKS FILLED WITH DIRT ETC. THIS WASH SHOULD BE PERFORMED THE DAY BEFORE YOU INTEND TO SEAL. THE CONCRETE MUST BE COMPLETELY DRY BEFORE APPLYING THE SEALER.  SOME SEALERS WILL WHITEN OR TURN MILKY WITH MOISTURE. (Rope off the area after pressure washing to keep ALL traffic off. The concrete must remain clean of debris for sealing. Otherwise you may trap dirt or debris under the sealer)

·            Exposed Aggregate is prone to rust spots which can be removed to a certain degree
·            Plain broom finish concrete is subject to more pop-outs especially in recent years.
·            Stamped concrete is subject to a colour loss. (Surface release agent colours can peel off with loss of sealer due to salt damage)
All Concrete Driveways, regardless of which style you have, may end up with a few pop-outs, the longer those are left unwashed and unsealed, they will turn into shaled area's over a few years.

Different contractors use different methods of applying sealers including the number of coats applied. At Rockscapes Concrete Service we use 3 coats of concentrated sealer diluted about 30-40% with Xylene. This slows down the curing process and allows the sealer to penetrate the concrete pores and adhere better. Our suppliers sell a version of our sealer that is “ready to use”, pre-diluted and easy to work with.

POPOUTS Source of Information on this can be obtained at concretesask.org Tech Tips Pop outs are caused by lightweight aggregates absorbing moisture and then freezing, expanding and
cracking or popping out of the surface. Fixes are difficult; we recommend keeping your driveway shoveled and dry, annual sealing with acrylic sealers to provide topical protection. Mild winters with less snowfalls, moisture mean less popouts and sealing required. Patches can be done, but may be noticeable. Our suppliers do sell products that can be used to patch concrete pop outs.

RUST MARKS - Very difficult work, we use an angle grinder with a wire wheel; we scrub with a 10% solution of Muriatic acid and rinse this off with clean water. It is important to wear safety gear during this job. (Protect your eyes and skin) Some contractors drill out the rust spots and then clean the rust stains in a similar method.

SEALING CONCRETE

If the concrete is dusting or shaling in any areas I recommend using a densifier sealer in those areas first. At Rockscapes Concrete Service we have used a product from Cornerstone Coatings and believe that it has made a significant difference. This is a water-based product and drying time will be required. After this step an acrylic sealer is applied. (Again Acrylic’s are topical sealers, and create a protective film on the surface.)

I believe in topical sealers (Acrylic) to protect and seal out salt and other destructive chemicals. These can be sprayed using quality sprayers like a Chapin. Again, proper drying time is required before allowing any traffic on the concrete. A guideline is 24 hours for driveways. Walkways and patios can be used once dry to the touch. Outside temperature will be a factor in drying time. During sealing with Acrylic sealers, grit can be sprinkled sparsely to provide traction. On a reseal, we recommend two coats of Acrylic. Most home-owners roll on the sealer with a 15 mil roller, paint tray, and handle. It is very hard to clean Acrylic sealer off your roller, At Rockscapes we dispose of used trays and roller cage handles

Source for buying your products,
Prairie Concrete - 30-3703 Kochar Ave – Saskatoon – 306-343-0770 (Kevin Mapes at Prairie Concrete is a very knowledgeable Concrete Expert )
_________________________________________________________
Article by John Groves, President Rockscapes Concrete Service. More information can found on Rockscapes at:
rockscapesconcrete.blogspot.ca
facebook.com/rockscapessaskatoon
#yxe #saskatoonconcretecontractor #saskatoon #Saskatoondriveway #rockscapessaskatoon #trustedsaskatoon



Tuesday, 29 March 2016

Densifier for Garage floors.... As an option?

WHY CONCRETE DENSIFIERS ARE THE NEW GARAGE FLOOR SEALER
updated 16 April, 2015 by Shea 37 Comments

Concrete densifier with sealer on a garage floor


A new trend that is slowly working its way into the garage is the use of a concrete densifier sealer on the garage floor.  Densifiers have been used on occasion in the garage for a variety of reasons, but rarely as an actual finished garage flooring treatment.  So why has there been a gradual increase in its use and popularity for the garage floor?
The reason is the addition of silicone and siliconate agents in some densifiers to act as a sealer.  This helps to create not only a water repellant floor, but one that is resistant to liquids in general.  So let’s take a closer look at how a concrete densifier with sealer on your garage floor may be beneficial for you.

HOW A CONCRETE DENSIFIER WORKS ON A GARAGE FLOOR
Concrete densifiers have been around for decades.  They are a concrete hardener and in the flooring industry used primarily for concrete floor polishing, abrasion resistance, anti-dusting, and in some cases to harden softer concrete surfaces before grinding.
Lithium densifiers are the most common choice used for garage floors. This is due to their ease of application and less reactive properties to carbon dioxide which can create a whitening effect on the floor. Unlike sodium densifiers, lithium densifiers also do a good job at repelling road salts. Once applied, the concrete retains its natural matte look.
When concrete cures, bleed water makes its way to the surface increasing the water to cement ratio, laitance content, and fine aggregates.  This is what helps to make the surface of concrete smooth, but it also creates a surface that is softer than the underlying cement.  When a densifier is introduced, the chemical reaction increases the surface strength of concrete from an average of 20% to 40% depending on the original pour and finish of the concrete.
It does this in two ways.  The densifier is a water based chemical solution that first works by penetrating into the surface of the concrete and reacting with calcium hydroxide to produce calcium silicate hydrate (CSH).  This is the substance that gives concrete its strength.  Next, the CSH that is produced fills the open pores of the concrete increasing its density.
It’s important to note that concrete densifiers are non-film forming, meaning that they don’t leave a topical film on the surface to protect it from liquids and staining.  This is why they haven’t been used much as a finished product for garage floors – until recently.
The addition of silicone and siliconate agents in densifiers creates a waterproofing agent right at the surface of the concrete.  This allows the concrete densifier to act as a sealer for your garage floor by repelling water, oils, chemicals such as road salts, and other fluids.  They can also be used over stained concrete.

Are they 100% impervious to stains and chemicals?  No, but if you don’t allow spills to sit for a long period, they will generally wipe right up with little if any scrubbing necessary.  Be particularly careful with solvents that can stain, as their resistance to them is minimal.