Colloidal Silica New Technology for Better Concrete

Transcription

1 Ron Blank & Associates, Inc Colloidal Silica New Technology for Better Concrete Course Number: lyt03a Please note: you will need to complete the conclusion quiz online at ronblank.com to receive credit An AIA Continuing Education Program Credit for this course is 1 AIA HSW CE Hour Lythic Solutions, Inc. Brad Sleeper P.O. Box 5028 Vancouver, WA brads@lythic.net Phone: Cell:

2 An American Institute of Architects (AIA) Continuing Education Program Approved Promotional Statement: Ron Blank & Associates, Inc. is a registered provider with The American Institute of Architects Continuing Education System. Credit earned upon completion of this program will be reported to CES Records for AIA members. Certificates of Completion are available for all course participants upon completion of the course conclusion quiz with +80%. Please view the following slide for more information on Certificates of Completion through RBA This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA or Ron Blank & Associates, Inc. of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

3 An American Institute of Architects (AIA) Continuing Education Program Course Format: This is a structured, web-based, self study course with a final exam. Course Credit: 1 AIA Health Safety & Welfare (HSW) CE Hour Completion Certificate: A confirmation is sent to you by and you can print one upon successful completion of a course or from your RonBlank.com transcript. If you have any difficulties printing or receiving your Certificate please send requests to certificate@ronblank.com Design professionals, please remember to print or save your certificate of completion after successfully completing a course conclusion quiz. confirmations will be sent to the address you have provided in your RonBlank.com account. Please note: you will need to complete the conclusion quiz online at ronblank.com to receive credit

4 Course Description Learn how colloidal silica nano-technology improves the integrity and beauty of exposed concrete floors. Explore the chemistry behind this technology, its innovations, and application processes.

5 Course Objectives By completing this course, the design professional will be able to: 1. Discuss the role of densifiers and colloidal silica technologies in terms of strengthening concrete. 2. Compare and contrast colloidal silica technology and silicate densifiers in terms of chemistry, performance, and application process and identify how these factors impact safety and the environment. 3. Discuss various colloidal silica concrete floor innovations and their application process. 4. Identify the benefits of using colloidal silica on concrete floors and how this impacts performance and longevity of a project.

6 Terms You Should Know Pozzolan a material which, when combined with calcium hydroxide, exhibits cementitious properties. Densifier substance applied to surface of concrete in order to fill pores and increase surface density. Diamond Polishing a process which uses diamond tooling to polish a floor to a high reflectivity. Burnish a process which uses non-diamond tooling or rubbing to polish a floor to a high reflectivity. Silicate a highly caustic compound containing metal salts (high ph). Reactive Colloidal Silica an engineered dispersion of nano-sized silica particles in an aqueous suspension, (no metal salts). Colloid a suspension of solid particles in a liquid. Amorphous without a clearly defined shape or form. Caustic able to burn or corrode organic tissue by chemical action. Nanometer one billionth of a meter.

7 Introduction

8 Concrete Concrete plays a crucial role in today s construction and design. It is a widely used building material made from cement, aggregates and admixtures such as water reducers, plasticizers, and fly ash. Its many uses in construction projects include architectural structures both large and small, foundations, exterior landscaping, roads, parking structures, bridges, and much more.

9 Strength and Flexibility The wide use of concrete stems from its strength and durability. With a long history of use in construction, many ancient concrete structures still stand tall today, attesting to its longevity. The ease-of-maintenance further contributes to its durability, while the flexibility of concrete lends itself to a vast array of projects and design applications.

10 Aesthetic Appeal Concrete is an increasingly popular choice for its aesthetic qualities in design, especially in flooring. Beautiful exposed concrete floors are common in restaurants, display rooms, high-end retail stores, museums, universities, and even homes. With its many aesthetic options for color, texture and levels of shine, concrete adds an appeal that s both timeless and modern.

11 Concrete Weaknesses Still, because Concrete is first and foremost a structural material, it requires specific chemical treatments and mechanical processing to overcome its inherent limitations as a finished surface material. Its porosity makes it prone to staining, its vulnerability to acid attack can cause surface etching, and its susceptibility to surface wear and dusting are natural characteristics of concrete that need to be considered for any finished protocol. Concrete hardeners, additives, and protectors are commonly used to help resolve these issues. Historically, design professionals have used silicates in flooring applications to densify and strengthen concrete. However, traditional silicates have many drawbacks including complicated application, whiting, and hazardous application byproducts.

12 New Technology Through the development of better chemistry, new reactive colloidal silica technology overcomes the weaknesses of previous concrete hardeners. Exhibiting a faster and more complete reaction with concrete, colloidal silica technology can now be found in a variety of concrete innovations. From densifiers to cleaners, the chemical makeup of this technology adds strength and durability more efficiently and effectively than hardeners of the past.

13 Applications The application of colloidal silica is easier and safer, requiring no rinse and no hazardous waste eliminating environmental impacts and health risks to those in contact. As a protectant, reactive colloidal silica improves the longevity and durability of concrete floors beyond what silicates have been able to provide. As a cleaner, colloidal silica continues to densify a concrete floor over time, creating a harder, longer-lasting, low maintenance floor.

14 Applications In an overlay system, colloidal silica reacts with and densifies cementitious and non-cementitious surfaces where silicates fail. As a curing agent, applying colloidal silica as soon as the surface is walkable creates a more complete reaction on the surface of the slab and, thereby, a harder finished surface. As an admixture, colloidal silica is the purest pozzolanic additive, reacting more quickly and completely with the concrete to provide early strength.

15 Colloidal Silica New Generation Technology

16 What Is Reactive Colloidal Silica? Reactive Colloidal Silica is the purest, most reactive advanced concrete treatment technology. Processed from silicates, its makeup consists of 99.5% pure silica suspended in an ultra-low surface tension liquid.

17 The Chemistry: Nano Technology The particle size of the silica in colloidal silica is significantly smaller than fumed silica particles at 5 nanometers. This creates a larger reactive surface which increases the volume of calcium silica hydrate, creating more CSH as it lowers the residual calcium hydroxide (a caustic crystalline byproduct) during and after cement hydration. CSH acts as a binder and imparts strength in concrete. When colloidal silica is added to concrete at the time of placement, compressive strength is increased. When added after hydration, the concrete surface is densified as silica penetrates the surface to bond to the silica and calcium hydroxide to create CSH.

18 How it Works Colloidal silica works by reacting with lime in concrete. During hydration, approximately 20 percent of a concrete mixture s portland cement is converted to lime, which has no structural value in concrete. However, colloidal silica pozzolanically reacts with lime to form CSH strengthening crystals.

19 How it Works Concrete also contains naturally occurring silica. Because silica bonds best to itself (a property not found in any silicate densifier) colloidal silica is able to build up more density and strength in a concrete surface. It can be applied to new, hard-troweled floors, or to existing slabs after light grinding. Colloidal Silica Microscopic view of pore in concrete

20 Non-Caustic The silica in colloidal silica is amorphous and will not produce hazardous crystalline dust. With a ph similar to baking soda, it contains less than one half of one percent metallic salts and is far safer to handle than silicates. No whiting

21 What It s Used For Applications to Design Projects

22 Colloidal Silica In Action Now, lets take a more in depth look at colloidal silica innovations and concrete treatments: Densifiers Silica polymer dispersion protectors Cleaners Overlayments Curing agents Admixtures

23 First-Generation Densifiers Chemical densifiers can help concrete to acquire a better polish and make that polish more durable because they increase abrasion resistance. First-generation concrete densifiers were made from silicates, such as sodium silicate and potassium silicate; this range of silicate-based compounds later broadened to include lithium silicate. These compounds are highly caustic, with a ph of 11 to 13, similar to the alkalinity of lime itself.

24 First-Generation Densifiers The process of applying these densifiers can generate a caustic, gelatinous slurry that must be thoroughly scrubbed off and disposed of as hazardous waste. The high ph (alkalinity) of silicates makes them unpleasant for applicators to handle. In fact, some cities and states are imposing tighter restrictions on how and where the slurry of silicate hardeners can be disposed of. Caustic material Hazardous waste disposal

25 Silicate Densifier Application Sodium silicates react with Calcium Hydroxide in concrete to liberate silica from the sodium ion that keeps it in suspension. Unfortunately, sodium will impede silica bonding as it competes with it for bonding sites. Silicates ratio of one part sodium to 3 parts silica is a limiting factor in the potential for densification of any concrete slab. Once applied, the densifier must be continuously agitated with a broom to assist in penetration and chemical reaction. Time for application can take up to 60 minutes or more. The silica/calcium hydroxide reaction creates a caustic gel which then must be diluted/hydrated with water to continue penetration, and then followed by more brooming.

26 Silicate Densifier Application After hydration, extraction of the surface residue is required to prevent whiting. Again, because silicates are caustic (ph 11-13), any residue or residual slurry must be treated as hazardous waste. Whiting from incomplete extraction

27 Colloidal Silica Densifiers Colloidal silica densifiers produce no excess mineral salts (which discolor concrete) and no whiting, even if over-applied. Due to a smaller silica particle size, reactive colloidal silica has more reactive sites on the molecule than silicates and, therefore, forms chemical bonds more readily. It fills the pore structure more consistently, making an extremely hard, dense floor surface that has increased wear resistance to foot and fork lift traffic. Damaged concrete that is soft and dusting can be improved with applications of colloidal silica, enabling the floor to take a polish.

28 Colloidal Silica Densifiers Colloidal silica is up to1000 times less caustic than silicates, making it safer for workers to handle and safer to use near other finished surfaces. Any application residue is non-toxic. Application of colloidal silica densifiers are easier and more simplified; and unlike some silicates, there is no overnight curing required speeding up project times. There is no disposal of hazardous material reducing environmental impacts and health risks. No hazardous waste

29 Colloidal Silica Densifier Application Application simply involves applying the densifier via a spray-pump applicator and reapplying as needed to keep the surface wet for 15 minutes. After the slab is allowed to dry for approximately one hour, it is ready for polishing to a high reflective shine. Overnight waiting is not required, consequently eliminating the extra transportation-related energy consumption of returning to the jobsite common when using silicate densifiers.

30 Colloidal Silica Densifier Application - Polishing Colloidal Silica Densifiers can be used in either a diamond polished or non-diamond polished (burnished) application. In either application, there is no removal step only a small amount of non-crystaline dry powder residue that is vacuumed up during the polishing process.

31 Alternative to Diamond Polishing Colloidal silica is also at the foundation of a new polishing alternative that provides all the benefits of a polished floor without the expense of diamond polishing. This non-diamond polished floor process uses the application of colloidal silica engineered in two nano sizes that effectively impregnate the surface with a veneer of silica that can be burnished to a reflective shine.

32 Non-Diamond Polishing Process The base layer of colloidal silica containing silica particles of 5 nanometers forms a bonding surface (or landing pad) for a second layer containing silica particles of about 45-nanometers. These larger particles quickly build up density in the surface and may actually fill in finer scratch patterns.

33 Non-Diamond Polishing Process After the floor dries (one hour), excess silica is picked up by a floor scrubber using a floor stripper pad and water. Again, there is no white crystalline residue to remove. An acrylic co-polymer protector solution formulated with silica and lithium is then applied and allowed to dry (one hour). The floor is then burnished to give it its final shine.

34 Why Non-Diamond Polished Floors? Industrial concrete floors have a high strength mix and are placed with a mechanically consolidated surface. The non-diamond polished alternative process adds reflectivity without grinding off the mechanically densified cap. And again, beautiful reflective surface floors are achieved while saving on expenses and other resources.

35 Savings Treating concrete floors with colloidal silica densifiers, whether used as a densifier in diamond-polished or non-diamond polished applications, consumes less resources and lowers costs saving on time, labor, and scrubbing equipment. The tables on the next two slide illustrate the savings of using colloidal silica in comparison to conventional silicate densifiers. Time Labor Equipment Materials Dollars

36 Savings Colloidal Silica Densifiers Conventional Silicate Densifiers Spray-On Application YES NO Scrub-in Application NO YES Potential Water Damage NO YES Application Time 15 min. 60 min Labor 1 worker 3 workers Equipment Hand Sprayer ($30) or Power Sprayer ($200) Autoscrubber ($6000) Set Time 1 hour 12 hours Scrub-Off Time NO YES Scrub-Off Labor NO YES Scrub-Off Disposal NO YES Spills of Scrub-Off Slurry NO YES Whiting Potential NO YES Autoscrubber Transport NO YES Autoscrubber Maintenance NO YES

37 Savings This is one example of an average cost comparison between Colloidal Silica treatments and Silicate-based treatments

38 Silica Polymer Dispersion Protector Colloidal silica technology can also be found in silica polymer dispersion protectors for treating concrete floor surfaces. This technology combines a water-borne modified epoxy polymer with reactive silica. The result is a breathable, densifying sealer that forms a tough, clear, chemically bonded protection layer which is also formulated to increase water repellency and traction. Third party lab testing with strong acid as well as with oil resulted in only mild discoloration after 24 hours of exposure. This discoloration buffed out of the protection layer easily; no permanent damage to the concrete occurred. Protects from etching, staining, etc.

39 Independent Testing Stain and Acid Etch Protection (motor oil, brake fluid, vinegar, red wine, acetone, muriatic acid) NO PENETRATION NO PERMANENT ETCHING Typical average COF for 800 diamond polish..65 to.75 dry.60 to.65 wet After application of protector.78 to.9 dry.70 to.80 wet

40 Independent Testing Abrasion Resistance: Three, 1 top sections of 4 concrete test cylinders were screened, densified and received one application of the protector. Testing was done on a Tabor Abrasor with two coarse carborundum wheels loaded with1 Kg. Samples were ground for 7.5 minutes achieving 500 cycles. Micrometer measurement showed significantly less wear on the treated samples compared to the untreated after 250 cycles. 2 of the 3 samples continued to show less wear through 500 cycles.

41 Silica Polymer Dispersion Protector A silica polymer dispersion protector can be easily applied using a microfiber applicator. It dries within two hours, and can be burnished to a deep gloss in hours. Its highly resilient surface re-shines easily with lightweight burnishing or scrubbing machines to help maintain a glossy, clean, attractive appearance with applications ranging from warehouses, to restaurants, to retail stores.

42 Colloidal Silica Cleaners A cleaner that incorporates colloidal silica technology not only removes dirt and other surface impurities, it also continually fortifies the floor surface. Whereas silicates do not bond, the colloidal silica within a cleaner molecularly bonds to the concrete surface, building a harder surface with each cleaning. Resistance to abrasion and liquid penetration is improved and floor maintenance is easier.

43 Colloidal Silica Cleaners These cleaners can be used in auto scrubber machine cleanings. No rinsing is required. They can also be used in mopping applications.

44 Colloidal Silica Overlay Systems Many cementitious overlays today are self-leveling systems made with specialty cements, as opposed to ordinary portland cement. These systems allow for minimal thickness buildup. These modified cement products have less residual lime available with which to react. These systems also exhibit lower abrasion resistance due to low aggregate content and benefit immensely from fortification with silica. However, with less Calcium Hydroxide available to them, silicate densifiers have such a limited opportunity to react that they are, for the most part, ineffective.

45 Colloidal Silica Overlay Systems Colloidal silica is chemically unique in its capability to react with the high silica content of specialty cement products to create a durable bonded topping with high reflectivity. It sometimes happens that the slab specified to be polished is not suitable. The polished overlay can add $6- $9 per sqft. more than the original spec in the budget. An overlay system utilizing colloidal silica technology and non-polished technique will add as little as $3-$5 per sqft. making it a cost efficient alternative as well.

46 Colloidal Silica Curing Agent When applied as a curing agent, reactive colloidal silica fills the pores at the surface of the newly placed slab and reduces water transpiration from the slab creating a longer period of cement hydration. The concrete cures at a higher strength because the added silica bonds with calcium hydroxide created during the cement hydration reaction.

47 Colloidal Silica Admixtures Admixtures are generally added to concrete mixes in order to increase workability, strength, and durability. Fly ash and silica fume are probably the most common admixtures used in cement mixes, known for their pozzolanic qualities. Pozzolans react with calcium hydroxide in cement to produce high strength and low porosity. Colloidal silica contains the same main pozzolanically reactive ingredient as fly ash and silica fume which is, of course, silica.

48 Colloidal Silica Admixtures The smaller the silica particles, the more potential for reaction. As stated earlier, the 5 nanometer size of silica particles in colloidal silica creates more surface area for greater reaction to occur improving early strength in the curing process as well as long-term strength throughout the life of a project. Fast reacting and facilitating a more complete curing process, workers are able to get on slab sooner cutting days off of construction schedules. Calcium Silica Hydrate Crystal

49 Case Studies

50 Eileen Fisher Clothing Store Irvington, NY In support of sustainability, a high-end retailer, Eileen Fisher, wanted to recycle 3000 square feet of space in the former Burnham Furnace works, a large 103-yearold building in Irvington, NY. For a highly sustainable flooring surface, they refurbished the existing concrete. Colloidal silica densifier was chosen for its sustainable and non-caustic qualities as well as for its time-saving application. The crew stained the floor gray to unify the varying shades of concrete, and then diamond-polished it to a high gloss. The grinding was time-consuming, but using the fast-applying and fast-acting colloidal silica densifier helped. They completed the job in one week. The owner was very pleased with the speed and beautiful result. It was the ability to maintain this floor for 20 years without petroleum products that will pollute the environment Most other floors need waxing and stripping, and all that goes down the pipe. Matt Johnson, owner of Savaspace Inc. and project Contractor

51 Killingworth True Value Killingworth, CT Killingworth True Value in Killingworth, CT was one of the first to integrate the colloidal silica, non-diamond polished alternative into their facility. Because construction took place during winter where temperatures were 40ºF, the application of epoxy would have normally required the building to be heated and temperatures maintained during an entire cure time of hours. The application of colloidal silica using the non-diamond polished process eliminated the need for heating, resulting in significant energy cost savings. The result is an abrasion resistant, cost effective floor that is attractive and is easy to maintain. When new, you can't tell the difference between a 400 grit [non-diamond polished, colloidal silica densified floor] and a 3000-grit diamond polish. Nathan Christner, Project Contractor

52 Korry Electronics Everett, WA A Washington state high-tech plant needed a floor that could stand up to abuse, was easy to clean, was cost effective to make, and looked good enough for entertaining guests. The facility is used for assembly of hightech avionics equipment. It has strict operating conditions, such as humidity controlled at 78%, and high attention to cleanliness. It is also frequently visited by customers. Acrylic flooring was considered not durable enough. Polished concrete offered the durability, appearance and easy maintenance they sought, but it was beyond their budget. Alternatively, colloidal silica densifier coupled with the non-diamond polished floor technique provided a durable, highsheen, easy-maintenance floor resulting in a savings of approximately $120,000. It s turned out to be a very tough floor...we drive tuggers and forklifts across it; we slide all sorts of things across that floor. It holds up well. Steve Sullivan, Maintenance Facilities Technician

53 EWEB Operations Center Eugene, OR The new Operations Center of the Eugene Water & Electric Board was attempting LEED Gold certification. The owner wanted an exposed concrete floor that was durable, stain resistant, and attractive. The floor was originally specified for hardening using a magnesiumflurosilicate hardener. However, it was feared that the extensive water-flushing needed by this product would allow the chemicals to contaminate the building s eco-friendly septic system. Instead, the contractor suggested densifying with a more eco-friendly colloidal silica densifier and protector, which does not require flushing. After allowing the surface to cure for twelve hours, it was then burnished with a high-speed floor burnisher and a fine diamond pad (1500-grit or 3000-grit) to achieve a reflective, slightly wet look. To protect this floor with an epoxy system would have cost $4-5 per sqft, a cost that was unacceptable to the owner. Protection with silica polymer dispersion solution cost was $0.75 per sqft., resulting in a substantial savings.

54 Course Summary

55 Course Summary Now the design professional will be able to: 1. Discuss the role of densifiers and colloidal silica technologies in terms of strengthening concrete. 2. Compare and contrast colloidal silica technology and silicate densifiers in terms of chemistry, performance, and application process and identify how these factors impact safety and the environment. 3. Discuss various colloidal silica concrete floor innovations and their application process. 4. Identify the benefits of using colloidal silica on concrete floors and how this impacts performance and longevity of a project.

56 Ron Blank & Associates, Inc Colloidal Silica New Technology for Better Concrete Course Number: lyt03a Please note: you will need to complete the conclusion quiz online at ronblank.com to receive credit An AIA Continuing Education Program Credit for this course is 1 AIA HSW CE Hour Lythic Solutions, Inc. Brad Sleeper P.O. Box 5028 Vancouver, WA brads@lythic.net Phone: Cell: