Ice Melters and Concrete Issues?????

I found this article published by the ACI about Ice Melters and thought it clarified some of the problems with using these products in a Freeze and Thaw climate. Especially when the aggregates in the concrete are porous and moisture absorbing. These lightweight aggregates absorb any moisture, when they freeze, they expand and create an ugly hole or pock mark in your concrete. Concrete Contractors and those in the industry, loosely refer to them as pop-outs. Annually applied Acrylic Sealers help to block the moisture from permeating the concrete surface, additives like SPG Vapor Lock, seal the concrete and reduce pop outs significantly.

In any event, if you are having troubles with shaling and popouts, read this article, keep your driveway shoveled and clean, do not push water or salty water out of your garage. And yes that shaling area under and around the rubber trim of your overhead door is the same symptom, moisture and freeze thaw. (mop up or shop vac that and dump on street.) And last, wash the salt out of garage, off driveway as early in spring as you can.

Here is the Article......

Ice Melters and Concrete

Winter brings the most picturesque scenes: families playing in the snow, friends around the fireplace and ski trips, but it also brings a rise in weather related problems. Of these, ice and its removal are among the most critical.  Unfortunately, there are a small percentage of those who crack their ice dilemma only to face another problem when spring arrives; damaged concrete.  There is much confusion surrounding this damage which is mostly caused by the freeze/thaw cycle. Too often people attribute concrete damage to the ice melter that was used. It is the purpose of this bulletin to help you better understand: the types of damage that happens to concrete, what causes them, and how to repair and prevent further damage.

Chemical Damage

According to the American Concrete Institute (ACI), which is a leading United States concrete authority that sets many of the guidelines and standards that are used today in the designing, planning, construction and inspection of concrete structures, there are several chemicals, some of which are used in ice melter formulas that actually attack concrete, and are best avoided. They are:

Aluminum Chloride, Ammonium Nitrate, Ammonium Sulfate ,Ammonium Chloride, Calcium Sulfate, Magnesium Sulfate, Magnesium Chloride, Sodium Cyanide

Freeze/Thaw Cycle Damage

By far the most risk of damage to your concrete during the winter months is attributed to the freeze/thaw cycle. To put this in sample terms, it is the build up of water [melted ice] being absorbed into the porous concrete, which then freezes and expands. This expansion within the concrete causes pressure to build up and eventually this build up will exceed the limit that the concrete was built to withstand. When the pressure becomes too much for the concrete to 

withstand, scaling generally occurs.

The concrete absorbing the melted ice [water] is a fact of nature and cannot be blamed on the ice melter used. It can be likened to a sponge absorbing water. However, it should be noted that when you use an ice melter, you will have more melted ice [water], and therefore the potential of more water seeping into the concrete than if you left the ice in its frozen state. Of course, not taking steps to remove the ice on a walkway may put yourself at risk from a liability standpoint, so what is one to do?

As mentioned earlier, the freeze/thaw cycle is a natural process and there is no way of eliminating it. However to reduce the damage caused by this cycle, we strongly recommend that after applying the ice melter and when the ice turns into slush, that the slush be removed from the concrete pavement, sidewalk or driveway to reduce the amount of water that may penetrate the concrete thus reducing the pressure build up.

Another way of reducing the damage caused by the freeze/thaw cycle is to use an ice melter that will keep melted ice in a liquid state for a longer period of time. For example, ice melter containing calcium chloride tends to re-freeze more quickly compared to ice melter containing potassium chloride. By using a potassium chloride product, you extend the time available for more melted ice [water] to drain off your concrete or evaporate, resulting in less water being absorbed by the concrete.

Another type of damage that can be attributed to the freeze/thaw cycle is a popout. Popouts occur due to internal swelling in the concrete causing small fragments of concrete to break away from the surface. Popouts are usually caused by highly absorbent rocks that are not capable of holding a lot of pressure. When freezing occurs under moist conditions, the rock will swell up and when there is sufficient internal pressure, the rock will break from concrete surface.

Repair & Prevention

Scaling and Mortar Flaking: Many things can be done to prevent or reduce the risk of this damage occurring. For example, concrete that is properly air-entrained - that is, concrete containing enough small air pockets – will better resist scaling and mortar flaking caused by the freeze/thaw cycle, since these air pockets help to cushion the pressure caused by freezing of the absorbed water. Another example, is to ensure your concrete is of the highest quality and standard. To this end, there are several important points that one should know:

• A high graded and durable concrete mix should be used.
• The concrete is to be properly sloped to ensure that water drains away from the slab.
• Proper finishing practices are also important for the creation of a strong concrete slab.
• The concrete must be cured promptly followed by an air-drying period.

How to Repair Freeze Thaw Damage

According to the Portland Cement Association (PCA), another leading concrete authority, that to protect against further freeze/thaw damage a breathable surface treatment may be applied on the concrete. Impermeable materials such as epoxies should not be used because moisture can be trapped in the concrete which could lead to further damage.

Oil treatment such as linseed oil, silane, siloxane, or other materials are recommended. Linseed oil treatment consists of two applicants. Combining equal parts of commercially boiled linseed oil with a solvent such as turpentine or mineral spirits, the recommended coverage for the first application is roughly 40 to 50 sq. yd per gallon [9-11 m/liter]. The second application should roughly be 70 sq. yd. gallon [15 m/liter]. To make sure that the oil treatment is successful, the temperature of the concrete at the time of application should be 50°F (10°C) or above. This allows for sufficient drying to take place.

Caution: The surface may be slippery after the application therefore the surface should be kept clear.

Popouts

There are several ways to minimize or eliminate popouts:

• Use concrete with the proper water-cement ratio.
• Use air-entrained concrete.
• Use a durable crushed-stone in the composition of your concrete.
• Slope the slab surface to ensure proper drainage.
• Reduce concrete temperature to 50°F to 70°F (10°C to 21°C).
• Do not finish concrete with bleed water on the surface.

To repair popouts, one can fill in the patch left behind with a dry-pack mortar, epoxy mortar, or other appropriate patch material. For a surface that has numerous popouts, a thin-bonded concrete overlay may be used to cover up the cosmetic detraction.

Damaged or New Concrete

It is not recommend that ice melter be used on damaged concrete. Damaged concrete will absorb the water [melted ice] more readily since its ‘seal’ has been broken and therefore can be more susceptible to damage. It is best to reseal or treat your damaged concrete as mentioned earlier, before using any ice melter on it. Further, it is recommended that for concrete less than 12 months old that NO ice melter be used. Newly poured concrete needs time to cure and settle. The application of ice melter on concrete less that 12 months old may weaken the concrete structure making it more susceptible to damage in the future. In order to reduce slipping, falling and liability risks, we suggest applying sand or gravel on the new concrete slab to give it some traction.

Ice Melter on Concrete

As important as it is for one to know the makeup of their concrete, they should also understand how various ice melting products will affect their concrete and its immediate environment. Sodium chloride for example, will attack the metal rebar contained within the concrete when it is soaked up into the concrete and also damages surrounding vegetation, soil structure and ground water. Calcium chloride, which tends to leave an oily residue on your concrete surface, will actually discolor concrete. It does this by accelerating the hydration process, while having a retarding effect on hydration of the ferrite compound in Portland Cement. Magnesium chloride, ammonium nitrate and ammonium sulfate attack and disintegrate concrete and should be strictly avoided.

On the other hand, urea will not chemically damage concrete, however it contains nitrogen, which breaks down to ammonia and is quite toxic to aquatic life. A great choice to consider for your concrete, is a fertilizer based ice melter, such as XYNYTH Manufacturing’s Mountain Organic Natural ice melter, which is potassium based. It actually reduces the change of damage to surfaces by preventing refreezing of the melted ice longer than other ice melters and by leaving no residue behind. It is also good for the vegetation and safe on the eco-systems.

Damage to concrete is rarely caused by the ice melter used but rather by the effects of the freeze/thaw cycle. Your risk of damage can be reduced substantially by remembering these few points: Remove slush and broken ice. Use a good ice melter products - prevent chemical damage - extend freeze/thaw cycle. Try to prevent water build up on surface to reduce absorption. Ensure that concrete is of high quality construction to withstand your cold weather climate. Do not use ice melter on new, damaged, or unsealed concrete.

This bulletin provides a general guideline on the causes of concrete damage and ways to repair and prevent them. For more detailed information, please consult your local ice melt distributor, The American Concrete Institute (ACI), The Portland Cement Association (PCA).

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

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 )

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Article by John Groves, President Rockscapes Concrete Service. More information can found on Rockscapes at:

www.rockscapes.org

rockscapesconcrete.blogspot.ca

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