Productions Team Inc. 2008 2009 ©

POLISHING BASICS 

  Table of Contents

1. Education
2. Polishing Basics
3. True Diamond Polishing
4. Diamonds
5. Wet vs. Dry Polishing
6. Standards for Polished Concrete
7. Benefits of Polished Concrete
8. Options with Polished Concrete
9. Environmental Impact
10. Health Benefits
11. Cost
12. Can All Concrete Be Polished?
13. Applications for Polished Concrete
14. Maintaining the Shine
15. Is Polished Concrete Slippery?
16. Equipment
17. Supplemental

1. Education   Polished concrete is a relatively new process.  We work hard with clients to ensure that they receive the education necessary to perform the process as well as educate their clients to know what True Diamond Polishing is. Polishing Basics  Simply put, polishing concrete is similar to sanding wood. Heavy-duty polishing machines equipped with progressively finer grits of diamond-impregnated segments or disks (akin to sandpaper) are used to gradually grind down surfaces to the desired degree of shine and smoothness.  The process begins with the use of coarse diamond segments bonded in a metallic matrix. Diamonds that have been graded to a particular grit are poured into a metallic matrix slightly softer than a diamonds they hold.  As the diamond grinds into the concrete and gradually wears away, the metal matrix wears away as well, revealing more fresh diamond to grind the concrete with.  Some of our diamonds can grind upward of 80,000 ft.² before being replaced. These segments are coarse enough to remove minor pits, blemishes, stains, or light coatings from the floor in preparation for final smoothing. Depending on the condition of the concrete, this initial rough grinding is generally a three- to four-step process. The heavier the machine and subsequently the grinding head, the more material comes off in a single pass.  Our stone extreme can take off as much as a quarter of an inch of concrete with an aggressive grit diamond. When it is necessary to remove coatings, more aggressive diamonds are used.  In grits usually ranging from 6 to 50, and the number of segments per diamond are fewer, resulting in a heavier head pressure on the floor.  This has an effect of creating a smooth profile, while removing coatings from the floor.  Coatings as thick as a quarter inch can be removed, and one or two passes. The next steps involve fine grinding of the concrete surface using diamond abrasives embedded in a plastic or resin matrix. Crews use ever-finer grits of polishing disks until the floor has the desired sheen.  For an extremely high-gloss finish, a final resin bond grit of 1500 or finer may be used. Experienced polishing crews know when to switch to the next-finer grit by observing the floor surface and the amount of material being removed.  Some resin bond diamonds are designed for wet grinding, some for dry grinding only.  Confusing the two can result in excessive loss of diamond life. 

2. Polishing Basics (cont’d) Some crews may attempt to skip resin steps or perhaps during the final polishing step, some contractors spread a commercial polishing compound onto the surface to give the floor a bit more sheen.  Skipping on the mechanical process to the addition of a densifyer or sealer equals less longevity and more walk off. It's important to note that once the process is started, grits cannot be skipped.  If you start with 50, you must proceed with each successively higher grit until you arrive at your final grit.  You cannot start with 50 and go to 200 etc.

3. True Diamond Polishing

Shadow 

 Indicates standard polishing steps under normal circumstances

6 Grit Metal matrix bond diamond (also available as coating removal)

 Used for aggressive removal on hard concrete surface & aggressive aggregate exposure

AutoScrub

 Clean floor thoroughly and properly

16 Grit Metal matrix bond diamond (also available as coating removal)

 Used for aggressive removal on hard concrete surface & aggressive aggregate exposure

AutoScrub

 Clean floor thoroughly and properly

30 Grit Metal matrix bond diamond (also available as coating removal)

 Used for aggressive removal on hard concrete surface & aggressive aggregate exposure

AutoScrub

 Clean floor thoroughly and properly

50 Grit Metal matrix bond diamond (also available as coating removal)

 Primary starting point for beginning the mechanical process of grinding/polishing concrete.  As your first cut, 4 passes should be made over the concrete.  To maximize diamond life, and cutting ability cutting wet is recommended when possible.  For all wet work, the cyclone slurry vac  is an invaluable tool.

AutoScrub

 Clean floor thoroughly and properly

100 Grit Metal matrix bond diamond

 Follows 50 grit. Continues to cut and open floor in process As your second cut, 2 passes are generally made over the concrete.

AutoScrub

 Clean floor thoroughly and properly

200 Grit Metal matrix bond diamond

 Follows 100 grit. Generally a prelude to Resin bond diamond cuts.  2 passes are generally made over the concrete.

AutoScrub

 Clean floor thoroughly and properly

400 Grit Metal matrix bond diamond

 May follow 200 grit in certain circumstances. Prelude to Resin bond diamond cuts.  2 passes are generally made over the concrete.

AutoScrub

 Clean floor thoroughly and properly

50 Grit Resin matrix diamond

 May be used in certain situations as a cutting resin to further expose aggregate and open floor.  2 passes are generally made over the concrete.

AutoScrub

 Clean floor thoroughly and properly

100 Grit Resin matrix diamond 

 If 50 grit Resin is used 100 must follow.  2 passes are generally made over the concrete.

AutoScrub

 Clean floor thoroughly and properly

200 Grit Resin matrix diamond

 General starting point for Resin bond diamonds.  2 passes are generally made over the concrete.

 True Diamond Polishing (continued)

Dye (requires autoscrubber)

 If the client desires a dye applied to the concrete it should be applied at this point in the process.  Dyes vary education is important.  

AutoScrub

 Clean floor thoroughly and properly

Densifyer

 After 200 Grit Metal putting densifyer in the floor will extend the life of the shine and protect the floor in the coming months.  There are a variety of densifyers.  Proper application is important.  For large square footage application the solution spreader is a key asset to maximize worker efficiency.  If not dyeing use Green Umbrella Hydro Shield.  If dye has been applied Green Umbrella Dry Shield should be applied at this time.

Shield & Enhance

 After dye protection is required.  Apply Green Umbrella Shield & Enhance at this point in the process to protect and enhance added color.

AutoScrub

 Clean floor thoroughly and properly

400 Grit Resin matrix diamond

 After densifying Resin polishing continues with a 400 Grit Resin matrix diamond.  2 passes are generally made over the concrete.

AutoScrub

 Clean floor thoroughly and properly

800 Grit Resin matrix diamond

 If the 400 sheen is too matte, continue to add shine with a 800 Grit Resin matrix diamond polish.  2 passes are generally made over the concrete.

1500 Grit Resin matrix diamond

 If still more shine and sheen is desired polishing may continue 1500 or 3000 Grit Resin matrix polish. 2 passes are generally made over the concrete. Final result will be a shiny final product.

AutoScrub

 Clean floor thoroughly and properly

Microfilm Application

 Perhaps a polished and densified surface isn’t all that will be required to maintain the surface.  The use of Green Umbrella Microfilm will enable you to provide a surface that is long lasting and easy to maintain.  It’s resistance to Aviation Oils and other potential surface contaminants make it the go to solution for protecting your newly polished surface.

Final Presentation

 Using an autoscrubber and a high speed propane burnisher present your client with the final product.

Diamonds There seems to be some confusion right now concerning diamonds. We hope we can be of some assistance sorting a few things out. The most important question you should have right now is – Am I getting what I’m paying for?   Specifically formulated for Productions. Our diamond bearing matrix (both metal and resin) is a proprietarily formulated blend. The longest lasting diamonds in the industry. The highest productivity.  Think about it, if I you aren’t wearing out your diamonds and constantly changing them, you are grinding, and that is where you are making money.  Less down time, longest lasting diamonds in the industry.   Above all the quality of cut that is being given the floor.  Grit does not equate quality of shine.   The bottom line is Your Productivity and Profitability. We, your Productions Team, have positioned ourselves to sell and support what we believe is the highest quality, most cutting edge technology System available.  Wet vs. Dry Polishing  Contractors can polish concrete using wet or dry methods, but typically they use a combination of both.  The wet process uses water to cool the diamond abrasives and eliminate grinding dust. Because the water reduces friction and acts as a lubricant, it increases the life of the polishing abrasives, particularly the resin-bonded disks, which can melt at high temperatures. One aspect of the wet process is the slurry, which must be contained. Crews must collect and dispose of the slurry that’s generated. We have many methods to help control, reduce and eliminate the waste slurry. Dry polishing requires no water. Instead, contractors use machines equipped with dust-containment systems that eliminate virtually all of the dust. Typically wet grinding is used for the initial grinding steps, when more concrete is being removed. As the surface becomes smoother, and crews switch from the metal-bonded to the finer resin-bonded diamond abrasives, they generally change to dry polishing. However, some diamond manufacturers have introduced resin-bonded disks that are designed to withstand the friction and heat of both wet and dry polishing. 

Certain slabs are extremely hard, concrete and aggregate strengths can exceed the abilities of dry grinding techniques. Often times wet grinding, with its increased cutting characteristics is the only reasonable alternative. While one can start the grinding process

dry and, if needed change it to wet, it is generally not advisable to start grinding wet and switch to grinding dry on the same slab. The process can change from job to job, and either method will result in a beautiful and lasting shine. Standards for Polished Concrete    There are not published standards for polished concrete, but it is generally agreed that the concrete must be polished through the sequence of grits ending with 800-3000 grit diamonds to be considered polished concrete. At the 800 grit level the concrete will exhibit a glossy sheen and high reflectivity without the use of a topical coating.  A gloss meter can be used to obtain reflectivity of the finished surface establishing a standard.  The concrete polishing standards that can be set for a particular job are simple and can be achieved by any contractor.  After a sample or demo has been done, and the client understands what results can be achieved, it is possible to write a specification for any job.

. Specify what grit to start from and finish with.

. Specify how many metal bond grits will be used.

. Specify how many resin bond grits will be used.

. Specify if a densifier will be used and what kind.

. Specify if a final protective coating will be used.

 True polished concrete in not simply exposing the rock in the concrete mix then applying a sealer. There's more to it than that.  While it is possible to polish a concrete floor without grinding it, the finish is not as brilliant, and the shine will not last. The finish tends to look irregular, like the suns reflection on choppy water.  True diamond ground and polished concrete looks like the suns reflection on a still pond, perfectly reflecting the beauty of nature that surrounds it.  The way to achieve this is by first giving the concrete a smooth profile, an even floor to polish.  We achieve this in several ways.  If control over the pour is to be had we encourage as flat a surface as possible.  If control over the pour is beyond our control, our equipment is designed to flatten out uneven spots in the floor.  The method of grinding we teach is a crisscross pattern to ensure not only a uniform coverage, but to smooth the whole floor as one entire cohesive, flat slab.

 True diamond polishing reveals what it reveals.  When working with an older slab, it's not possible to know or predict how thick layer of cream on top of the aggregate is.  Therefore, one cannot say how much aggregate will or will not be revealed.  True diamond polishing is indeed a work of art.  It is not like solid color painted surface, and one should not expect to be able achieve such.  One can guarantee though, that it will be beautiful, shiny and durable enough to last a lifetime.

  Benefits of Polished Concrete  True diamond polished concrete is extremely durable.  It can endure an extreme amount of abuse by everything from foot traffic, grocery carts, industrial machinery, cars, trucks to forklifts. Making full use of  highly durable, low-maintenance materials, such as concrete, extends the useful life cycle of a sustainable structure and reduces maintenance and replacement costs. During the polishing process an internal impregnating sealer, or densifier is applied. The densifyer sinks into the concrete and is invisible to the naked eye. It not only protects the concrete from the inside out, it also hardens and densifies the concrete. This eliminates the need for a topical coating, which reduces maintenance significantly (versus if you had a coating on it).  At Productions we train our contractors to bring the concrete to a full polish-  never needing to apply a topical coating or wax. Waxing the surface would be defeating the purpose of a  polished floor- because the concrete floor itself is already shining, so there is no need to put something on the floor that would then need to be maintained.            

   Options with Polished Concrete   If the decision is made to polish concrete in advance of the concrete being poured, there is a stunning array of available options: 

. Colored aggregate can be applied to the concrete mix or .seeded. into the top layer of the mix. The polishing process will reveal this aggregate. 

. Integrally colored concrete can be used. 

. Glass can be .seeded. into the mix. The polishing process will reveal the glass pieces. 

. Nails, bolts, computer chips, or any other objects can be seeded into the mix and then polished smooth. 

. Of course, any of these options can be combined together or into a pattern. 

. As noted earlier, polishing concrete required a series of polishing steps culminating with the use of 800-3000 grit diamonds. Each step in the process increases the shine and reflectivity of the concrete. 

. There are other options, which though they stop short of 800-3000 grit diamonds, are still beautiful: 

. Two steps of grinding to smooth most imperfections, then applying a topical sealer, might be called the .exposed aggregate, sealed look.. While still taking on a polished look, the polish is a result of a topical coating (still beautiful, but requiring more maintenance). 

. Some contractors produce a finish they call a .honed finish. where they stop at 400 grit diamonds. This .honed finish. has some surface shine, but is still smooth and easy to clean. 

. Other contractors let customers review the floor at the 400-800-and 1500 grit diamond level of shine if the customer is unsure if they want a fully polished look (though most clients do want the floor fully polished). 

Clearly, there are many levels of floors that stop short of truly being .polished concrete., but are beautiful in their own right. 

Environmental Impact Concrete floors, stained with nontoxic pigments, are a healthier alternative to carpeting because they do not emit harmful VOCs and are easy to sweep clean. In fact, VOC emissions from concrete building products are much lower than those for most other building materials.  Concrete polishing using green, low VOC densifiers increases the positive environmental impact on any project. Add in the potential of clean burning propane powered equipment and you have a very green solution.  Health Benefits  The health benefits of cutting concrete wet are well documented.  In many states OSHA requires wet saw cutting of all Portland products.  Polished concrete won’t hold dust, toxic mold, or pollens like carpet can.  It is environmental using the green product of concrete in a dual functionality, foundation and finished flooring.  Propane powered equipment is green, it’s cordless, and has endless run-time.  Cost The cost comparisons are numerous when it comes to the value of polished concrete.  Implementation varies depending on job size, scope, and location.   We try to educate all our clients that in the long run, a properly completed mechanical process coupled with an appropriate maintenance program will result in substantial savings for years to come.   

Can All Concrete Be Polished? Almost any structurally sound concrete floor, whether new or old, can be polished. But there are some exceptions. Most cracks are not an issue and can be easily repaired. Slabs that have heaved excessively or are crumbling should be replaced.  For new floors, no special mix design is required to achieve good results. Generally speaking, the floor should be in place 28 days before polishing begins to ensure adequate curing. Some of our contractors however, have been able to start grinding in as little as 7-10 days. There are times when the whole process can be done in phases, polishing can be completed at a later time. Ask us for direction. Some retail and warehouse facilities that plan to polish their floors after placement may specify the installation of as smooth a floor as possible to minimize the polishing steps required. Flatness specifications can be required of the slab installer that will help lessen the time and effort required to grind and polish. This can eliminate a large percentage of the grinding. Existing floors typically require some surface preparation prior to polishing to remove dirt, grease, coatings, or blemishes. However, floors that are wavy, need extensive patching, or are extremely porous may not be good candidates for polishing. An experienced contractor can usually determine a floor’s suitability.  To help solidify and densify polished concrete surfaces, some contractors apply penetrating hardeners to the concrete, normally after the second step of the grinding process. These products, which can be applied to new or existing floors, work by reacting chemically with the concrete to form a hard, crystalline structure. They also prevent dusting of concrete and offer extra protection from water penetration and staining.       

 Applications for Polished Concrete Because polishing is a multistep process, customers can choose the level of sheen—from satin to high-gloss—that meets their maintenance and aesthetic requirements. This versatility makes polished concrete an ideal flooring material for a variety of applications. Polishing contractors say their primary customers include: 

. Large warehouses and warehouse outlets 

. Retail stores 

. Hotels and restaurants 

. Office buildings 

. Auto showrooms 

. Private residences 

Ease of maintenance is the key reason many warehouses and retail facilities are opting for polished concrete. Not only are polished floors easy to clean, requiring only occasional damp mopping, they hold up well to heavy forklift and foot traffic. They also eliminate the need for messy waxes or coatings—as well as the associated labor, time, and expense to apply them. What’s more, the glossy surface resists the marks of forklift truck tires and staining from oil and chemical spills.   The high light reflectivity of polished concrete is another important benefit, especially for office buildings, hotels, restaurants, and other public facilities that want to project a bright, clean, professional image. Some customers simply want a look that’s unique. Polishing can give concrete a higher degree of shine—similar to polished marble or granite—than can be achieved with a high-gloss coating. This makes polished concrete a particularly good alternative for homeowners or businesses that can’t afford marble or granite floors but want the same brilliant, mirror-like finish. To replicate the color of stone, some contractors will sometimes apply stain to the concrete during the polishing process or polish concrete that has been integrally colored. It’s also possible to produce a terrazzo look by grinding through the top few millimeters of the concrete surface to expose the aggregate.   

 Maintaining the Shine  Although keeping polished concrete shiny requires minimal effort and expense, some regular care is necessary.  We recommend a simple maintenance program of occasional dusting to remove grit and damp mopping with a Productions Team Inc recommended cleaning product to enhance the shine. These products can be applied with a mop or auto scrubber.   A recommended cleaning with black scrubbing pads should also occur.  Occasional buffing with a high speed propane burnisher can bring back and even richen the shine.  With basic cleaning, polished concrete should keep its luster for years. Eventually, though, the shine can dull, especially in high-traffic areas. Fortunately, it’s easy to restore the gleam. If necessary, the floors can be lightly repolished with a fine-grit resin bond matrix diamond. It is not however, necessary to repeat the entire process from scratch.  Is Polished Concrete Slippery? Kept clean and dry, polished concrete floors are generally no slicker than plain concrete surfaces. And they tend to be less slippery than waxed linoleum or polished marble. The following readings were taken using the .Sellmaier. slip tester, and reveal an increased slip resistance as polishing progresses to it’s final grit. 

Equipment The professionals in this industry have concluded that corded machines are hindering the full potential of polishing equipment performance.  Go Cordless!  It has become our motto and is providing you the ability to go anywhere and demonstrate a polished surface.  To take three-phase power on site for a demo is often thought of as impractical because of cost and logistics. It is our equipments ability to be demonstrated anywhere that has sold a job time after time.   Why propane over electric?  Job after job we have seen problems arise when using electric.  No electrician for proper hook-up, no generator, no diesel to run the generator, cords in the way of equipment operators on-site, and the list goes on.  Propane is a well known, highly attainable, clean burning resource.  Operators aren’t left with downtime due to electrical issues.  Propane is the wave of the future.      

 Supplemental  Concrete finish floors are good for your nose and your bottom line because they are an energy efficient and environmentally sound option for your home or business.  Concrete finish floors are a good choice for: 

  Aesthetics  

 A wide range of attractive colors and patterns are available (depending on finish type) to compliment any design scheme. 

  Easy cleaning and                                                  maintenance  

 Only needs mopping and an occasional re-application of protective densifier or resin bond polish.

  Durability  

 Concrete never needs replacing. 

  Energy efficiency  

 The mass of concrete helps stabilize indoor temperatures.

  Allergy relief  

 Concrete won’t hold dust, mold, dust mites, or pollens like carpeting can. 

  Keep cool  

 Concrete stays cool like ceramic tile. 

  Economics  

 Concrete finish floors save on long-term costs like energy bills, maintenance, and replacement. 

  Environmental  

 Concrete finish floors conserve resources by using the same material to perform two functions--foundation and finish floor. 

  Flexibility  

 Allows you to change the look of your home or business by rearranging area rugs/area floor coverings, without the expense of tearing out carpet or tile. 

 Price and durability depend on the coloring method used: 

 Option 1 - Dye added to concrete mix at the plant. Integral color hides chipping but is not commonly done due to high cost. 

 Option 2 - Dye powder sprinkled onto concrete at finish stage and troweled in by concrete installer. Color is slightly below the surface, so minor chipping is hidden, more economical than option 1. 

 Option 3 - Color stain applied to the surface of the concrete after it has dried completely. Good for remodeling as well as new construction, unlimited palette, pattern, and price. 

When and how to plan for concrete staining:     When planning to use integrally colored concrete, optimize the use of concrete by designing your foundation to use just enough but not too much, since integral color has a higher cost.   Scoring and staining is possible for all concrete surfaces: steps, porches, patios, sunspaces, countertops, and fireplace surrounds.   Extreme care must be taken at every stage of the construction process when staining is to be employed: 

 • Be sure to write all special conditions into your subcontractor specifications/agreements. 

 • Supplement this by telling all subcontractors that the floor is to be finished and exposed, and that they are responsible for stains from adhesives, coffee, sodas, and chipping from falling tools or tear-outs. Plumber’s adhesive and red chalk are particularly detrimental. Plumber’s adhesive will bleach the floor and prevent it from taking the stain properly. Red chalk cannot be removed from the floor—blue chalk is okay. Sawdust, lumber, and construction debris must be kept off the floor at all times as these can draw moisture out of the concrete, affecting the staining process - be diligent and repeat yourself when necessary. 

 • Protect the floor after staining with cardboard or silverboard, and make sure you work the replacement costs for these items into your bidding. 

Why Concrete Is a Healthy Alternative

By Anne Balogh

On average, we spend 90% of our time indoors—and most of that time we are in our own homes, according to Angela Dean, author of Green By Design. Yet, we are increasingly using products containing volatile organic compounds (VOCs), in some cases creating indoor air quality that is 20 to 30 times more toxic than outdoor air, she warns.

The Healthy House Institute reports that indoor air pollution is the cause of about 50% of illnesses. Common sources of this pollution include outgassing from toxic paints and finishes, carpeting, manufactured wood products containing glues high in formaldehyde, dust mites, mold spores, mildew, and some cleaning products. When it comes to poor indoor air quality, carpeting is one of the worst offenders. New synthetic carpeting can outgas over 100 different VOCs. And whether made of synthetic or natural materials, carpet is difficult to clean and becomes a haven for dust particles, pollutants, and bacterial growth. Tens of millions of microorganisms can be found in a square foot of carpeting. Carpet can also be a major source of mold, especially if it becomes wet and the water isn't removed completely. Concrete floors, stained with nontoxic pigments, are a healthier alternative to carpeting because they do not emit harmful VOCs and are easy to sweep clean. In fact, VOC emissions from concrete building products are much lower than those for most other building materials, according to PCA. The use of natural lime-cement plaster wall finishes and concrete countertops can also significantly reduce total VOC concentrations inside a home. Exposure to toxic mold in homes and buildings has been blamed for ailments ranging from headaches to severe respiratory infections and immune system disorders. Mold can thrive on any organic material, especially in warm, moist, humid conditions. In addition to carpeting, mold can feed on drywall and wood studs, joists, and wall sheathing. Concrete floors and walls won't support the growth of toxic mold.

A brief overview of Concrete and Chemical Hardeners

 The most common building material today is concrete.  It is a used in building construction, consisting of a hard, chemically inert particulate substance, known as an aggregate (usually made from different types of sand and gravel), that is bonded together by cement and water.  In 1756, British engineer, John Smeaton made the first modern concrete (hydraulic cement) by adding pebbles as a coarse aggregate and mixing powered brick into the cement. In 1824, English inventor, Joseph Aspdin invented Portland Cement, which has remained the dominant cement used in concrete production. Joseph Aspdin created the first true artificial cement by burning ground limestone and clay together. The burning process changed the chemical properties of the materials and Joseph Aspdin created stronger cement than what using plain crushed limestone would produce.   Concrete that includes imbedded metal (usually steel) is called reinforced concrete or ferroconcrete. Reinforced concrete was invented (1849) by Joseph Monier, who received a patent in 1867. Joseph Monier was a Parisian gardener who made garden pots and tubs of concrete reinforced with an iron mesh. Reinforced concrete combines the tensile or bendable strength of metal and the compressional strength of concrete to withstand heavy loads. Joseph Monier exhibited his invention at the Paris Exposition of 1867. Besides his pots and tubs, Joseph Monier promoted reinforced concrete for use in railway ties, pipes, floors, arches, and bridges.  Today we have removed the aggregate that was used 40 years ago, remove the metal that was used to reinforce concrete, we add fiber, water reducers, plasticizer, and hardeners.   Today concrete is not the same as the product that was invented in 1756, or even the same product that was being used even ten years ago. Each step in the evolution of densifiers has been in direct response to the changes in concrete, and the perceived deficiency of the older products. Older densifiers were designed to work with the concrete that was being produced at the time.  As concrete has changed the products that are being used in conjunction with concrete have changed.  In the beginning it was okay to just harden concrete, then customers wanted the concrete to resist oils.  Today the government, employees and customers demand safer products that perform better than the products that have been available in the past.   

Chemical Hardeners include three basic categories of chemicals: silicates, silicinates and silica Silicates - penetrate and harden.  They are not a good sealers.  Disposal of the waste material is currently an issue.  

1) The oldest is Magnesium Fluorosilicates, which have been around since 1905.  This type of product requires multiple applications with varying rates of dilution.  

2) Sodium Silicates developed initially in German in the 1930’s.  Application of the product requires that it be applied at an average of 200 square feet per gallon, spread and worked until the surface tension is broken, mist with water, allow to gel a second time and then rinse and wet vac to remove. 

3) Potassium Silicates.  The main difference between the sodium silicates and potassium silicates is sodium is more prevalent in the North American and potassium is predominate in Europe.

4) Lithium Silicates. Lithium silicates were developed to combat Alkali Silica Reaction (ASR).  ASR is more prevalent in exterior applications where there is a constant source of water.  Lithium silicates are less susceptible to soluablization than sodium or potassium.  One of the by products of this particular silicate is its ability to reduce sweating on slabs.

A. Lithium vs. Sodium and Potassium(Li vs. Na and K)

a. The smaller size of the Li ion of the SiO2/Li2O molecule vs. the Na or K ion is important. 

b. The location of the Li ion in the SiO2/Li2O molecule is also important.  The Li ion is .close., actually touching the SiO2, while Na and K are .distant..   The inter-atomic distances of Na and K make them more available to react quickly with the available Ca or CaOH.  The quicker the reaction, the less penetration is able to occur.

c. With silica to Li ratio of 20:1 vs. 3:1 for Na, the lithium silicate is more .potent., relative to the silica content which is what reacts with the free Ca and CaOH to form C-S-H. (calcium-silicate-hydrates) In addition, when LiSiO2 reacts, it does not produce free Na or NaOH, (sodium hydroxide) which can raise the pH of the concrete surface.  

d. Na and K remain soluble in water. This solubility allows them to undergo expansion/contraction cycles with wet/dry cycles.  Li becomes insoluble and remains stable throughout these environmental changes.

In summary, lithium silicate has about 1/5 less .interfering. mass as a sodium silicate.  This is the true beauty of the lithium and one in which size really matters.  The smaller lithium ion stabilizes the silicate ions more efficiently with less mass and fewer molecules, resulting in improved performance while not contributing to higher pH levels.  Naturally occurring sulfates of sodium, potassium, calcium, or magnesium are sometimes found in soil or in solution in ground water adjacent to concrete structures [ Or in sodium or potassium silicates added to concrete as hardeners]  The sulfate ions in solution will attack the concrete.  There are apparently two chemical reactions involved in sulfate attack on concrete.  First, the sulfate reacts with free calcium hydroxide which is liberated during the hydration of the cement to form calcium sulfate (gypsum).  Next, the gypsum combines with hydrated calcium aluminate to form calcium sulfoaluminate (ettringite) .  Both of there reactions result in an increase in volume.  The second reaction is mainly responsible for most of the disruption cause by volume increase of the concrete (ACI 201.2R). . .  (b) Symptoms.  Visual examination will show map and pattern cracking as well as general disintegration of concrete..  EM 1110-2-2002 20 June 95 (www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-2-2002/c-3.pdf)  

Silicinates - excellent sealer, poor hardening characteristics.  Real world typical life expectancy is 18 to 24 months, and then it should be reapplied.  Disposal of the waste material is currently an issue.  

1) Silicinates are applied the same way silicates, spray, scrub, mist, rinse, and vac.

2) Silicinates can offer increased abrasion resistance over silicates in the short term due to the coating effect of the silicinates.

3) Silicinates are either potassium or sodium.

Silicas – are the newest and most promising of the chemical hardeners

 1) Silicas are applied simply by spraying them on the surface of the slab and allowing them to dry.  The surface should be clean and void of any curing compound.  Application rates are between 400 to 600 square feet per gallon.  Unlike silicates or silicinates there is no scrubbing and rewetting of the product.  Unlike silicates or silicinates there is no waste material to dispose of.    2) Silicas increase abrasion resistance over silicates or silicinates by up to twice as much 3) Silicas do not contribute to ASR 4) Silicas do not raise the pH of the concrete since the product is neutral 6.5.

5) Silicas have the highest increase in abrasion resistance

6) Silicas reduced labor

7) Silicas no hazardous waste to remove or dispose 

8) Silicas do not contribute to silicosis and are not carcinogenic unlike silicates which do contribute to silicosis and are carcinogenic

9) Silicas will not contribute to sweating or efflorescence

10) Silicas performance is not contingent on dwell time unlike silicates or silicinates

  There are features and benefits to each of these types of chemical hardeners.  The upside for the silicates is that they harden better than silicinates, Silicinates seal better than silicates.  Silicates have been directly linked to silicosis.  Silicates and silicinates have been tagged as carcinogens.  Silicates and silicinates must be disposed of as hazardous material.  There is significant research that documents the ill effects of sodium, potassium silicates and silicinates on reactive aggregate in concrete.  Currently the best technology for chemical densifiers is amorphous silica.