Super-Krete® Products Surface Preparation Guide

TABLE OF CONTENTS Surface Evaluation – The following methods, tests and standards can be used to evaluate the • Surface Preparation of Concrete Substrates condition of the concrete substrate and the • Choosing the Right Equipment effectiveness of the surface preparation procedure. • New Concrete • Existing Concrete Strength – The direct tensile strength of the • Guide for Selecting Surface Preparation concrete substrate should be determined prior to Methods placement of coatings and surfacing materials. • Industry Specifications for Surface Preparation Contaminants – The presence of grease, wax, or oil may be detected by dropping a small amount SURFACE PREPARATION OF CONCRETE of muriatic acid and a small amount of water onto the concrete prior to preparation and after All concrete substrates surfaces will require surface preparation to determine the condition. preparation prior to the installation of a polymer coating, decking or flooring system, including Contaminants Tests – There are several easy tests crack, spall and joint repair, resurfacing, topping, to determine if the concrete substrate is underlayment or overlayment. contaminated. 1. The surface exposed to drops of muriatic The first step in these operations is extremely acid should react, if there is no reaction it critical. The best materials correctly mixed and suggests the presence of contaminants. applied are doomed to fail unless the concrete 2. If the water droplets bead up and the substrate is properly prepared. At a minimum the water is not immediately absorbed, it concrete substrate must be prepared in suggests the presence of contaminants. compliance with minimum standards for the system to be placed per ACI, ASTM, ICRI, NACE, PCSI IMPORTANCE of CONCRETE pH and SSPC Standards. pH is believed to stand for “potential hydrogen” Deleterious surface contaminants and deteriorated or “power of hydrogen” and it is measured on a concrete must be removed, repaired if necessary negative logarithmic scale. The pH scale ranges and the surface roughened and cleaned. There from 0 to 14, and a pH of 7 (de-ionized water) is are many different techniques, methods, and types considered to be neutral. of equipment, which can be used to effectively prepare concrete. A strong acid may have a pH of 1-2, while a strong alkaline base may have a pH of 13-14. A Shot blasters, water blasters, scarifiers, scabblers, pH near 7 is considered to be neutral. acid etching, etc. are some of the commonly used equipment and techniques for surface preparation. pH is an approximate measure of acidity or alkalinity and is defined as the negative logarithm General – Concrete surfaces to be bonded must be scale of the hydrogen ion (H+) concentration. As clean and sound, which in all cases requires some the pH of a solution increases, the number of free form of substrate preparation. hydrogen ions decreases, and a change in pH of one reflects a tenfold change in the H+ concentration. For example, there are 10 times as

Page 1 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

many hydrogen ions available at a pH of 7 than deionized water. Place several drops of at a pH of 8 and at a pH of 9 there are 100 times water on a clean surface of concrete, (10 times 10) fewer hydrogen ions. forming a puddle approximately 1 in. (25 mm) in diameter. Allow the puddle to set The industry standard is that the concrete surfaces for 60 +/-5 seconds, then dip the pH must be sound and free of all bond-inhibiting paper into the water. Remove substance, which normal have a pH below that of immediately, and compare to chart to properly prepared concrete. determine pH reading. Other pH testing methods such as pH pencils or pH meters, Carbonated concrete is contaminated concrete, it or both, are available and may be used is not sound durable concrete, it is weak concrete, to measure pH. especially low pull-off strengths, therefore, it must be removed. Steel-reinforced concrete (wire-wire, Readings at or above a pH of 10.0 are ideal for rebar, dowels, etc.) is used throughout the world most epoxy primer, but may be too high for some in the construction of bridges, marine structures, non-epoxy adhesives. Refer to resilient flooring or parking garages, and buildings. The alkaline decking manufacturer’s written instructions for environment of the concrete protects the steel from guidelines. corrosion; however, this protective environment can be disrupted due to the migration of chloride There is always a question regarding is the surface ions to the steel and/or to carbonation of the clean enough, free a curing compounds, and other concrete. bond breakers, prior to the installation of coating or flooring system? Sound and durable concrete is highly alkaline, with a of pH 10.0 or above and it will passivates A simple litmus test is an inexpensive and quick the steel. A pH below a pH 10 is week concrete, way to see if the mechanical or chemical concrete subjecting the steel to oxidation (rusting) and the preparation treatment has adequately prepared concrete to internal stresses (spalling, cracking, the surface. The litmus test (paper or pencil or etc.) resulting from the oxidized steel increase in equipment) should always be run when testing volume expansion. Which is why a pH 10 or Moisture Vapor Emissions per ASTM F1869 greater, is recommended. Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using ASTM F710 - Standard Practice for Preparing Anhydrous Calcium Chloride. Concrete Floors to Receive Resilient Flooring: ICRI Selecting and Specifying pH Testing—Concrete floors shall be Concrete Surface Preparation tested for pH prior to the installation of resilient flooring. Levels of pH shall not (SSPC highly recommends that individuals exceed the written recommendations of involved in the coatings and surfacing the resilient flooring manufacturer or the industry obtain ICRI [International adhesive manufacturer, or both. Concrete Repair Institute] Guideline NO. 310.2R Guide for Selecting and To test for pH at the surface of a concrete Specifying Concrete Surface Preparation slab, use wide range pH paper, its for Sealers, Coatings and Polymer associated pH chart, and distilled or

Page 2 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

Overlays, text and physical profile samples.) Aggressively prepared substrates, such as those methods listed as CSP 6 and above should be Concrete Substrate Profiles, at a minimum, must examined for micro-cracking prior to placement of comply with ICRI Guideline No. 310.2R – a coating or overlayment. If micro-cracking has Selecting and Specifying Concrete Surface taken place, re-prepare the substrate with a less Preparation for Sealers, Coatings and Polymer aggressive method to remove the weakened Overlays, however SSPC does not recommend substrate, such as methods ranging from CSP 2 – Detergent Scrubbing or Low-Pressure Water CSP 5. Cleaning or Acid Etching as stand-alone methods of surface preparation. These processes can be Preparation Methods used in conjunction with others. CSP 1 Detergent Scrubbing CSP 1 Low-Pressure Water Blasting Great care must be taken not to “bruise” the CSP 1 – 2 Acid Etching concrete when using aggressive methods of CSP 1 – 3 Grinding surface preparation. Bruising causes micro- CSP 2 – 5 Abrasive Grit (Sand) Blasting cracking, which will weaken the substrate at the CSP 3 – 8 Steel Shotblasting surface. Since proper surface adhesion, especially CSP 4 – 9 Scarifying for those systems subjected to stresses relies on the CSP 5 – 8 Needle Scaling tensile strength of the substrate and tensile CSP 6 – 9 High/Ultra High Pressure Water adhesion of the system installed upon the Jetting substrate. CSP 7 – 9 Scabbling

CSP Methods Acceptable to SSPC - Require Meeting the Minimum Acceptable CSP (Concrete Surface Profile) Method listed below:

CSP 2 Sealers 0 – 3 mils (0 – 75 µm) CSP 2 – 3 Thin Film Coatings 4 – 10 mils (100 – 250 µm) CSP 3 – 5 High Build Systems 10 – 40 mils (250 – 1000 µm) CSP 4 – 6 Broadcast 50 mils – 1/8 inch (1250 µm – 3 mm) CSP 4 – 6 Self-Leveling 50 mils – 1/8 inch (1250 µm – 3 mm) CSP 5 – 8 Overlay Systems 1/8 – 1/4 inch (3mm – 6mm)

Page 3 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

ICRI CONCRETE SUBSTRATE PROFILES

Page 4 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

CHOOSING THE RIGHT SURFACE particles carried by water rising to the surface of PREPARATION EQUIPMENT freshly placed concrete) and is usually unsuitable for proper adhesion of coatings, toppings, or Before starting a concrete preparation job, overlayments. consider the following: Acid etched surfaces require flushing and • Does the concrete have an existing coating or neutralization before coatings or toppings are surfacing that needs to removed? What is it, applied, and it usually only recommended when and what are its properties? other methods of surface preparation cannot be • What is the thickness of the concrete, used. overlayment, or coating? • What is the current condition of the concrete, Formed concrete pours should be vibrated to and what is it’s in place tensile pull bond minimize pockets and holes, and to maximize strength? (ACI 503R or ASTM D7234) densification. Suitable form facing material should • What type of material will be placed or be used to produce a smooth form finish as applied? described in ACI 302.1R. If the surface has been • What is the concrete coverage thickness over cured with conventional curing compounds, or is reinforcement steel, if any? contaminated with form oil or other release agents, it must be completely cleaned by mechanical or Failure to consider all concrete issues per ACI chemical abrasion. 201.1R can cause result in significant mis- calculation the required method and production EXISTING CONCRETE SUBSTRATES rates of the surface preparation selected. The wrong material(s) could be specified for use. Existing concrete substrates should be sound and Environment, Health and Safety potential impact durable or in need of restoration prior to placement must be considered, such as volatile organic content of a polymer coating or overlay. If contamination is regulations, odor threshold, dust, dirt, noise, waste- discovered, the first requirement is to isolate the water and waste materials/packaging and surrounding surface(s) from the contaminated disposal, suppression, etc.? areas.

After all of these concerns are addressed and When the concrete is sound, but contaminated, it answered, an educated choice regarding the type should be cleaned. It then may be chemically of equipment and surface preparation techniques etched or mechanically abraded in the same can be made. manner as preparing new concrete thereby obtaining a laitance free surface. If the concrete NEW CONSTRUCTION substrate surface is deteriorated, the surface must be reduced to a sound and durable concrete by In new construction, proper planning prior to abrasive blasting, high pressure water blasting, pouring a concrete slab can minimize problems chipping, scarifying, or other suitable means to later (ACI 302.1R Guide for Concrete Floor and remove all loose or deteriorated material from the Slab Construction). When trowelled finish is used or surface. In some cases, the existing concrete is in an existing slab has a trowel finish, the concrete surface is smooth and slick with laitance (cement

Page 5 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

such poor condition that it must be replaced and 7. Steam Cleaning treated as new concrete. 8. Stripping 9. Etching – Acid (ASTM D4260) NEW & EXISTING CONCRETE 10. Shot Blasting STANDARDS 11. Abrasive Grit (a.k.a. sand) Blasting (ASTM D4259) Concrete surfaces to be covered with polymer 12. Wet Sandblasting coatings or surfacing systems must be sound, 13. Water Blasting durable and dry (in most cases) during installation and cure. The Concrete Industry Standard is that SURFACE PREPARATION METHODS PCC be at least 28 days and Fly Ash PCC at least 56 days old before it is coated or surfaced. 1. BUSH HAMMERING – Bush hammering is a method for roughening or correcting defects in The Concrete Industry Standard is not the Polymer the concrete substrate surface by impacting it Industry Standard. After 28 or 56 days the concrete with a device having a serrated face with has reached the majority of its strength and the rows of round or pyramidal hardened steel majority of cement hydration has taken place. points. Bush hammering produces a However, the excess water, not used in the roughened surface by removing the top layer hydration of the cement, slowly migrates out of the of concrete substrate. Fine particles are concrete reaching a homeostasis with its removed, exposing intermediate and larger environment in around twelve months. size aggregate. Concrete slabs should be placed in compliance with ACI 302.1R Guide for Concrete Floor and Slab Bush hammering is usually not recommended Construction, ACI 318 Building Code Requirements because of the impact damage it may cause to for Structural Concrete and SSPC/PCSI TU-10. underlying sound concrete. If bush hammering Concrete that is damaged or fails to comply with is required, it must be followed by grit-blasting the conditions set forth in ACI 302.1, ACI 302.2, with a small projectile to remove micro-cracked ACI 318, ACI 503.1-.4 and ACI 503R-Appendix A or micro-fractured concrete. The degree of and SSPC/PCSI TU-10 and SSPC-SP 13/NACE micro-cracking is dependent upon the size of No. 6 must be brought into compliance prior to the hammer, the impact force exerted and the placement of a coating or surfacing system. See quality of the concrete. reference to industry standards, ACI, ASTM, ICRI, Damage caused during the removal of bad PCSI and SSPC. concrete includes damage to the underlying GUIDE FOR SELECTING SURFACE concrete cement-gel matrix, including rupture of PREPARATION METHODS the larger aggregate’s mechanical lock in the matrix, thereby causing a “bruised” layer to be 1. Bush Hammering (not an approved method) formed approximately 1/8 inch (3.18 mm) to 2. Scabbling (not an approved method) 1/2 inch (6.35 mm) below the surface, 3. Horizontal Planing resulting in low cohesive strength of the 4. Scarifying concrete. The most important physical property 5. Sanding, Grinding for placing a coating and surfacing 6. Scraping

Page 6 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

applications is the tensile strength of the and are only recommended for use per the concrete substrate at the bonding surface. instructions addressed under bush hammering above. It must be used in conjunction with other Bush hammering is not approved for use alone approved methods of concrete surface as the only method of surface preparation. It preparation. can be used if followed by a non-impacting, non-vibrating method such as grit-blasting to insure that the “bruised” concrete layer is Advantages: removed. It must be used in conjunction with • Extremely aggressive other approved methods of concrete surface • Removes large amounts of material preparation. (quickly) • Removes most deleterious materials Advantages: Disadvantages: • Extremely aggressive • Can be highly abusive to concrete • Removes large amounts of material substrate (quickly) • Requires a skilled operator • Removes most deleterious materials • Dusty and dirty Disadvantages: • Must be used in conjunction with other • Can be highly abusive to the concrete methods of concrete preparation substrate • Requires a skilled operator 3. HORIZONTAL PLANING – Horizontal • Dusty and dirty planing is a method of improving the flatness of • Must be used in conjunction with other a concrete slab by mechanically removing methods of concrete preparation irregularities utilizing a machine fitted with multiple rows of high speed closely spaced 2. SCABBLING – Scabbling is a method for vertical cutters. roughening the surface of concrete similar to a bush hammering, utilizing a scabbling machine Horizontal planing can be used to remove fitted with air actuated cylinders faced with paints, coatings, adhesives and laitance. rows of round or pyramidal points of hardened Followed by a vibration free method, it can be steel, arranged for impacting the concrete used to remove epoxies, rubber-like coatings, substrate with great force and velocity. overlays, and low cohesive concrete.

Scabblers are designed to remove the top layer Advantages: of concrete substrate, exposing and fracturing • Extremely effective the intermediate and large aggregates to • Removes large amounts of material produce a very rough surface. Scabbling is (quickly) particularly useful for removal of thick, hard • Removes most deleterious materials overlayments such as epoxy mortars, setting • Levels substrate beds, pre-topped and cast-in-place concrete • Dust reduction shrouds available capped slabs. These machines act in exactly Disadvantages: the same manner as a hand held bush hammer • Highly expensive

Page 7 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

• Requires a skilled operator fully remove the laitance, especially cure-and- • Without excellent dust recovery, seal sealers. Concrete substrate “polish-gloss” extremely dusty must be removed, exposing the aggregate profile. 4. SCARIFYING – Scarifying is a method for removing heavy buildups of surface Advantages: contamination or other substances from • Low cost, relatively low equipment cost concrete substrate, utilizing a mechanical • Fast operation especially for light removal action similar to horizontal planning. Scarifiers • Removes most deleterious materials are heavy machines equipped with hardened • Can get into tighter places than most steel cutters vertically aligned and arranged on mechanical method of surface preparation a large, horizontal cylinder that rotates at high • Dust free or dust reduction shrouds velocity. Scarification will impact and partially available remove the concrete surface in closely spaced Disadvantages: parallel lines. It must be used in conjunction • Can give “false” sense that surface is with other approved methods of concrete properly surface preparation. • Prepared, when unground • Slow, when deep removal is required Advantages: • Without excellent dust recovery, • Extremely aggressive extremely dusty • Removes large of material (quickly) • Removes most deleterious materials 6. SCRAPING – Scraping is a method for • Dust reduction shrouds available removal of surface films from concrete utilizing Disadvantages: the scraping action of hardened steel cutting • Can be highly abusive to concrete blades arranged on counter-rotating horizontal substrate discs. Scraping is particularly useful for removal • Requires a skilled operator of thick elastomeric coatings and traffic decking • Without excellent dust recovery, materials, heavy concentration of tile mastic extremely dusty and carpet adhesive. Scraping is not a final • Must be used in conjunction with other surface preparation method. It must be used in methods of concrete preparation conjunction with other approved methods of concrete surface preparation. 5. SANDING & GRINDING – Sanding and grinding are methods of cleaning and Advantages: scratching the surface of concrete substrate by • Low cost abrasion utilizing sanding disks or abrasive • Effective impregnated grinding wheels. This method • Removes otherwise difficult to remove produces a finely scratched surface finish free materials of surface laitance and contamination and a • Limited to dust free portion of surface fines. Extreme care must be Disadvantages: taken to sand and grind “long-enough” and • Creates waste that can be costly to “deep-enough” into the concrete substrate to remove

Page 8 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

• Must be used in conjunction with other 8. CHEMICAL STRIPPING – Chemical methods of concrete preparation stripping is a method of surface preparation utilizing chemicals to soften or dissolve cured 7. STEAM CLEANING – Steam cleaning is an films to facilitate their removal. Chemical effective method for removal of many forms of stripping of contaminating films from concrete contamination that is present on the concrete is usually confined to small areas that cannot be substrate. Steam cleaning machines produce prepared more effectively. Like scrapping, quantities of wet steam, directed at the concrete stripping requires additional surface in a high concentration and at a velocity preparation prior to coating. Chemical sufficient to loosen, soften, and remove the stripping is not a final surface preparation contaminants. Steam cleaning coupled with method. It must be used in conjunction with detergents, degreasers, and other chemicals other approved methods of concrete surface greatly increases its effectiveness. Steam preparation. cleaning will only remove surface contaminants and only a small amount of contamination Advantages: within the pores of the concrete. Steam • Low cost cleaning is not a final surface preparation • Fast operation method. It must be used in conjunction with • Removes material other approved methods of concrete surface • Dust free preparation. Disadvantages: • EHS issues odor, VOC and chemical Advantages: exposure • Low cost • May not be “Legal” in some locations • Fast operation • Removal, transportation and disposal • Removes material could be extremely costly • Dust free • Used in conjunction with chemicals Disadvantages: cleaning could cause later problem, such • Hot, can cause burns to the operator as corrosive damage of metals • Elevated temperature can affect low • Introduces chemical into the concrete temperature Heat Deformation Materials, substrate that may be deleterious to bond such as plastics, causing deformation of some materials • Requires proper and adequate drainage • Used in conjunction with chemicals 9. ETCHING-ACID (ASTM D4260) – cleaning could cause later problem, such Etching-Acid works well on horizontal non- as corrosive damage of metals surface-hardened and non-cure-and-seal • Introduces water into the concrete concrete substrates. Thickened etching-acids substrate that may be deleterious to bond are available for vertical surfaces. Acid etching of some materials does roughen the concrete surface, but does not • Must be used in conjunction with other remove laitance and may not loosen other methods of concrete preparation materials that are acid resistant. (SSPC C.7.1 seldom recommends acid etching.)

Page 9 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

Acid etching is often accomplished with a 10% Pressure should be a minimum of 2,500 PSI at solution of hydrochloric (muriatic) acid or an the nozzle for adequate results. The use of aggressive citric acid. The concrete substrate pressure washing assures the removal of the should be pre-wetted to assure uniform etching acid weakened and etched surface layer of of the surface. One gallon of muriatic acid or concrete. This is conducive to promoting better citric acid should be spread over 50 to 75 sq. adhesion of subsequently applied coatings, ft. (5 to 7 sq. m.) of concrete and allowed to surfacing, toppings, etc. stand for five minutes, coupled with aggressive scrubbing with a stiff bristle broom. ASTM D4262 - Standard Test Method for Determining the pH of Chemically Cleaned or The surface should be immediately rinsed with Etched Concrete Surfaces. The test utilizes pH fresh water to avoid formation of “bonded” salt Test Paper in final rinse water on the concrete deposits. This procedure should be repeated surface. A strip of test paper should be dipped until the concrete has the texture of fine in the rinse water remaining on the surface. sandpaper. The surface should be thoroughly After the paper changes color, it should be rinsed following each etching and the final compared with the color chart accompanying surface checked with pH paper to assure that it the paper to determine acidity or alkalinity. The has been neutralized. pH reading of the fresh rinse water should also be taken. The pH reading from the rinse water Citric Acid - In place of using muriatic acid, on the concrete surface should not be more than citric acid can be effectively used to etch 1.0 pH unit lower or 2.0 pH units higher than concrete surfaces. The use of citric acid offers the fresh rinse water. If it is, the surface should some advantages, such as: be further neutralized with fresh water and • Can be used at low concentration 5-10% retested until the pH is acceptable. Two • Has a relatively moderate pH, 3.5 – 4.0. readings should be taken on random sections of • Low toxicity factor every 500 sq. ft. (50 sq.m.) of concrete. • Safer to handle • No harsh vapors during etching, does not Advantages: interfere with other work in the immediate • Minimal equipment area • Fast operation • Rinse and power wash • Creates uniform profile (may require multi- applications) Citric acid can be purchased from, among • Can easily get into “tight places” others, The Pfizer Chemical Co., Pfizer • Dust free Inc. Groton, CT 06340. Disadvantages: • EHS issues, especially with acid Neutralization - Regardless of which acid is concentrates used for etching the concrete substrate, it must • Does not remove acid resistant be neutralized with clean water, preferably with contaminates two steps, first a low-pressure rinse to remove • May not be “Legal” in some locations spent acid volume, followed by a high-pressure • May require re-claiming of all spent bi- rinse to move embedded and surface residue. products, even if neutralized

Page 10 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

• Used in conjunction with chemicals cleaning could cause later problem, such Normally, shot blasting is coupled with as corrosive damage of metals that may grinding or other methods of surface be deleterious to the bond of some preparation, which is required for “can’t get to materials areas” with shot blast equipment, such as under encumbered areas. 10. SHOT BLASTING – Shot blasting is an effective, relatively clean and dust-free (or dust- Preparing concrete surfaces using shot blasting reduced) method for removing hardened films generally results in concrete substrate removal of contamination, and for texturing the concrete of up to 0.125 inch (3.18 mm) per pass. If substrate by impacting the surface with high surface laitance alone are to be removed or if velocity metal abrasive. Shot blasting medium the surface is to be prepared for thin (< 35mil) is available in a range of different sizes and a coatings, the steel shot abrasive should be fine. limited number of particle shapes. The blasting Using fine shot coupled with moving quickly, medium is thrown against the concrete will produce a light etch on the concrete substrate from a high velocity wheel. The substrate similar to a brush blast. If a thick film abrasive scours the concrete surface, rebounds topping or overlay is to be installed, a deeper and is recaptured for continued use. The texture must be achieved, which will produce abraded surface fines and other contaminants surface profiles (IRCI-CSP) illustrated above. are captured by a vacuum system. Three parameters control the depth of surface The pulverized concrete, spent abrasives, dust profile or concrete removal: and contaminants are removed by a separate • The mesh size of the shot (surface profile vacuum dust collector. The reclaimed steel shot is proportional to shot size) is then recycled to the blast wheel. Shot blasting • The amount of shot flow to the surface, machines are intended to be fully enclosed and which is controlled (increased or provide an excellent means of cleaning and decreased) by the operator. texturing concrete substrates, without the use of • Speed of travel over the concrete substrate water or etching chemicals, and with a minimal determines cut. The slower the travel release of airborne dust and contaminants. speed the more concrete is removed and Shot blasting, using small shot, will provide a correspondingly the greater the depth of clean, physically sound concrete substrate, with cut. a relatively uniform texture ranging from fine granular to a coarse sandpaper finish. Heavy Advantages: shot can damage micro-crack or micro-fracture • Free of vibration the concrete substrate in a similar manner to • Fast operation other aggressive surface preparation methods. • Very good keyed surface Shot blasting is particularly useful and cost- • Dry surface effective on large, unobstructed floors, decks, • Removes material of the same strength or and other horizontal concrete surfaces. In lesser strength addition, there is shot blasting equipment for • Dust free vertical surfaces.

Page 11 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

Disadvantages: Hardness Scale, where talc is a 1.0, and • Not very effective on rubber like diamonds are 10.0. Grit abrasives having • Elastomeric coatings or adhesives Mohs Hardness of less than 6.0 are too soft to • Does not reach the edges or corners clean and texture concrete at high production effectively rates. Grit that fractures along cleavage planes, • Horizontal equipment does not operate on such as aluminum oxide, garnet, etc. remain vertical surfaces, such as curbs angular and do not polish like silica sand. The higher the impact velocity the greater the 11. ABRASIVE BLASTING – Abrasive Blasting rate of production and the greater the rate of are methods for cleaning and texturing the breakdown-fracturing of the abrasive. Reuse of concrete substrate by impacting it with a high fractured abrasives, called the next generation velocity stream of fine aggregate (silica sand or or fines, should be mixed with the large other medium) projected by compressed air. abrasives. The blasting medium usually consists of hard, angular aggregates of a size range selected to The use of sand, grit, or shot impelled under be most effective. Sandblasting produces a high pressure gives a variety of results by textured, physically sound substrate free of adjusting: surface contamination and fines. • Abrasive Material (hardness and shape) • Impact Speed The actual surface hardness of concrete and • Motion and Speed of the Nozzle or depth of desired profile should determine Machine whether abrasive (silica sand or other medium) blast cleaning is the best concrete preparation Advantages: method. Test areas should be tried, using the • Free of vibration same equipment, air pressure, and abrasive • Fast operation you would intend to use. Production rates, • Very good keyed surface dusting, and cleaning profiling (roughening) • Dry surface effects should be noted. EHS concerns • Removes all material of the same strength regarding siliceous materials continues to or lesser strength reduce the annual use of silica sands, while Disadvantages: other abrasives are seeing a corresponding • Dust (pollution, silicosis, health hazards) increase in demand. • Not very effective on rubber-like surfacing • Through the high velocity of the abrasive Larger abrasive grit sizes are used for particles, the impact on the rebar is so preparing concrete than are used on steel. Grit heavy that there is a change in the abrasives having an 8 to 12-mesh size are molecular matrix structure of the recommended for heavy cleaning and superficial layer of the rebar which cuts profiling. If only the removal of concrete down on the rebar’s resistance to laitance is required, a 20-40 mesh size grit corrosion gradation is sufficient. Grit abrasives should have angular to sub-angular particle shapes and be at least a 6.0 on the Mohs Mineral

Page 12 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

12. WET GRIT-BLASTING – Wet grit-blasting Disadvantages: is a hybrid surface preparation method • Supply, handling and disposal of water whereby abrasive grit is injected into a stream • Usually more costly than other methods of high velocity water, and the solution is • Requires highly skilled operator directed at the concrete substrate surface in a • Substrate normally are required to be dry manner similar to sand and water blasting. Often referred to as grit injected water blasting, 13. WATER-BLASTING/HYDRO this method of surface preparation produces a DEMOLITION – Water blasting or hydro clean, physically sound profile of varying demolition are methods of removal of concrete degree, free of contamination and fines. surface contamination and fines from a concrete surface by impacting with an Due to the many variations and operating extremely high velocity stream of water. Water parameters associated with water blasting, a blasting and hydro demolition are normally complete description is presented below: used to remove significant thicknesses. This surface preparation method is usually more Water Blasting – high water pressure cleaning. difficult to control than other methods of The use of water impelled under high pressure blasting and appears to produce greater gives a wide variety of results by adjusting: surface profile irregularities. However, water • Stand-Off Distance blasting may be preferable if it is imperative to • Water Pressure avoid airborne particulates, such as blasting • Water Volume aggregate residue, cement particles, • Nozzle Shape contaminates, dust, etc. Water blasting • Trajectory (Angle of Attack) produces a surface texture of widely varying • Abrasive Grit Wet Blasting degrees, free of contamination and fines.

Basic rules: Hydro-demolition sometimes referred to as • The Flow Rate Normally Decreases as the hydro-blasting or hydro-jetting is one of the Pressure Increases (use of smaller orifice most efficient methods of removing and to increase pressure) preparing concrete. Hydro-demolition does not • Pressure and Flow Rate Decreases as produce the “bruised” micro-cracked layer, as Abrasives are Introduced Into the Water do other mechanical methods previously Stream. discussed. Water pressures associated with hydro-demolition is selective in its concrete Advantages: removal process. That is, it can be adjusted to • Relatively clean operation (except water remove concrete to a specific depth, remove and grit residue) poor unsound concrete until good sound • Fast operation concrete is reached. Recent industrial research • Relatively low noise operation shows that hydro-demolition prepared concrete • Good keyed surface profile has produced tensile bond interface strengths • Removes material of the same or lesser far superior to bush hammering or scabbling. strength Tensile bond strength tests performed on hydro- demolition prepared concrete have been

Page 13 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

measured at more than double (2x) the strength from others can change without notice, Arizona for concrete prepared by bush hammering. Polymer Flooring cannot be held at fault if any of the information conveyed in good faith is deemed Terminology - Although there is little consensus in error. Listed below is a number of Trade within the industry, the term high pressure is Association Organization that can provide generally used to describe pressure up to additional assistance to the reader. 1,000 bars (15,000 PSI), ultrahigh pressure is above that level (commonly used with current Questions: Contact Arizona Polymer Flooring equipment = 2,500 bars = 35,000 PSI)

Advantages:

• Dustless • Free of vibration (does not bruise Arizona Polymer Flooring concrete) 4565 W. Watkins St. • Relatively clean operation (except water Phoenix, Arizona 85043 and grit residue) Phone: 623.435.2277 • Fast operation www.apfepoxy.com • Relatively low noise operation • Good keyed surface profile • Removes material of the same or lesser

strength

Disadvantages:

• Supply, handling and disposal of water • Usually more costly than other methods • Requires highly skilled operator

• High pressure water can be very dangerous Substrate normally are required to be dry •

DISCLAIMER

Arizona Polymer Flooring Technical Bulletins are developed in good faith for the sole purpose of assisting others with products, systems and industry standards. The information published herein is gathered from different sources that are thought to be reliable, but the reader should not assume that the information absolves the reader from validating information from other sources, such as listed below, before making a decision. Since information

Page 14 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

AMERICAN CONCRETE INSTITUTE ASTM F1869 Standard Test Method for STANDARDS Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using ACI 201.1R Guide for Making a Condition Anhydrous Calcium Chloride Survey of Concrete in Service ASTM F2170 Standard Test Method for ACI 201.2R Guide to Durable Concrete Determining Relative Humidity in ACI 302.1R Guide for Concrete Floor and Slab Concrete Floor Slabs Using in situ Construction Probes ACI 302.2R Guide for Concrete Slabs that

Receive Moisture-Sensitive Flooring

Materials INTERNATIONAL CONCRETE REPAIR ACI 318 Building Code Requirements for INSTITUTE STANDARDS (ICRI) Structural Concrete

ACI 364.1R Guide for Evaluation of Concrete ICRI Guideline No. 310.1R Structures Prior to Rehabilitation Guide for Surface Preparation of ACI 503R Use of Epoxy Compounds with Deteriorated Concrete Resulting Concrete from Reinforcing Steel Corrosion ACI 503.1 Standard Specification for ICRI Guideline No. 310.2R Producing a Skid Resistant Surface Selecting and Specifying on Concrete by the Use of a Multi Concrete Surface Preparation Component Epoxy System for Sealers Coatings and ACI 503.4 Standard Specification for Repairing Polymer Overlays Concrete with Epoxy Mortars ICRI Guideline No. 320.1R ACI 546R Concrete Repair Guide Guide for Selecting Application

Methods for the Repair of

Concrete Surfaces AMERICAN SOCIETY FOR TESTING OF IRCI Guideline No. 320.2R MATERIALS Guide for Selecting and

Specifying Materials for Repair ASTM D4258 Standard Practice for Surface of Concrete Surfaces Cleaning Concrete for Coating

ASTM D4260 Standard Practice for Acid Etching SOCIETY OF PROTECTIVE COATINGS Concrete (SSPC STANDARDS & JOINT ASTM D4262 Standard Test Method of pH of STANDARDS) Chemically Cleaned or Etched Concrete Surfaces SSPC-TU 2/NACE 6G197 ASTM D7234 Standard Test Method for Pull-Off Design, Installation and Maintenance of Adhesion Strength of Coating on Coating Systems for Concrete Used in Concrete Using Portable Pull-Off Secondary Containment SSPC-SP 13/NACE Adhesion Testers No. 6 Surface Preparation of Concrete SSPC- ASTM F710 Standard Practice for Preparing TU 10/PCSI Procedures for Applying Thick Film Concrete Floors to Receive Resilient Coatings and Surfacings Over Concrete Floors Flooring

Page 15 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.

Super-Krete® Products Surface Preparation Guide

ORGANIZATION CONTACT INFORMATION

ACI (American Concrete Institute), P.O Box 9094, Farmington Hills, MI 48331 (http://www.aci- int.org)

ASTM International (American Society for Testing of Materials), 100 Barr Harbor Dr., West Cohshohocken, PA 19428 (http://www.astm.org)

ICRI (International Concrete Repair Institute), 1323 Shepard Drive, Suite D, Sterling, VA 21064 (http://www.icri.org)

NACE International (The Corrosion Society), 1440 South Creek, Houston, TX 77084 (http://www.nace.org)

SSPC (The Society for Protective Coatings), 40 24th St., 6th Floor, Pittsburgh, PA 15222 (http://www.sspc.org)

Page 16 of 16 – December 21, 2016 Super-Krete Products Surface Preparation Guide Super-Krete Products is a division of Arizona Polymer Flooring, Inc.