1、SSPC-Guide 20May 5, 20141SSPC: The Society for Protective CoatingsTechnology Guide No. 20Guide for Applying Thick Film Coatings and SurfacingsOver Concrete Floors (replaces SSPC-TU 10 of same title)1. Scope and DescriptionThis Guide discusses techniques and procedures to select and apply resinous co
2、ating systems over concrete floors. These thick-film systems (greater than 500 micrometers m 20 mils) include self-leveling systems, slurry systems, broadcast systems, mortar systems, fabric-reinforced systems, spray applied systems, and non-waterproofing and underlayment membranes. Application of t
3、hin-film coatings (less than 500 m 20 mils) and sealers, terrazzo flooring, membrane systems designed for waterproofing, and primary and secondary containment systems is beyond the scope of this Guide. The Guide is intended for use by floor surfacing contrac-tors, owners and specifiers, and others i
4、n the coatings and surfacings industry. 2. Referenced Standards and PublicationsThe latest revision of the standards below should be consulted for reference: 2.1 SSPC GUIDES, STANDARDS AND JOINT STANDARDSSSPC-AB 1 Mineral and Slag AbrasivesSSPC-AB 2 Cleanliness of Recycled Ferrous Metallic Abrasives
5、Surface Preparation of ConcreteSSPC-Guide 12 Guide for Illumination of Industrial Painting ProjectsDesign, Installation, and Maintenance of Coating Systems for Concrete Used in Secondary Containment Design, Installation, and Maintenance of Protective Polymer Flooring Systems for Concrete2.2 INTERNAT
6、IONAL CONCRETE REPAIR INSTITUTE TECHNICAL GUIDELINES (ICRI) No. 310.1R Guide for Surface Preparation of Deteriorated Concrete Resulting from Reinforcing Steel CorrosionNo. 310.2 Selecting and Specifying Concrete Surface Preparation for Sealers, Coat-ings, and Polymer Overlays No. 320.1R Guide for Se
7、lecting Application Methods for the Repair of Concrete SurfacesNo. 320.2R Guide for Selecting and Specifying Materials for Repair of Concrete Surfaces2.3 AMERICAN CONCRETE INSTITUTE STANDARDS (ACI) ACI CT-13 ACI Concrete TerminologyACI 201.1R Guide for Conducting a Visual Inspec-tion of Concrete in
8、ServiceACI 201.2R Guide to Durable ConcreteACI 224R Control of Cracking in Concrete StructuresACI 302.2R Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring MaterialsACI 308R-01 Guide to Curing ConcreteACI 318 Building Code Requirements for Struc-tural Concrete and CommentaryACI 364.1R
9、 Guide for Evaluation of Concrete Struc-tures Before RehabilitationACI 546R Concrete Repair Guide2.4 ASTM INTERNATIONAL ASTM D4060 Standard Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser ASTM D4260 Standard Practice for Acid Etching ConcreteASTM D4262 Standard Test Meth
10、od for pH of Chem-ically Cleaned or Etched Concrete SurfacesASTM D4263 Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet MethodASTM D7234 Standard Test Method for Pull Off Adhesion Strength of Coatings on Concrete Using Portable Adhesion TestersASTM D7682 Standard Test Me
11、thod for Replication and Measurement of Concrete Surface Profiles Using Replica Putty ASTM E1745 Standard Specification for Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill under Concrete SlabsSSPC-TU 2/ NACE 6G197SSPC-TR 5/ NACE 02203/ICRI 710.1SSPC-SP 13/NACE No. 6SSPC-Guid
12、e 20May 5, 20142ASTM E1643 Standard Practice for Selection, Design, Installation, and Inspection of Water Vapor Retarders Used in Contact with Earth or Granular Fill Under Concrete SlabsASTM F1869 Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Sub-floor Using Anhydrous C
13、alcium ChlorideASTM F2170 Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ ProbesASTM F2420 Standard Test Method for Determining Relative Humidity on the Surface of Concrete Floor Slabs Using Relative Humidity Probe Measurement and Insulated Hood 2.5 US De
14、partment of Transportation, Federal Highway Administration Alkali-Silica Reactivity Field Identification Handbook3. DefinitionsAmine Blush: Surface opalescence (blush) on coating films caused by reaction of amine co-reactant with carbon dioxide and water to form an amine carbamate. This can affect a
15、dhesion of any subsequent coat if not properly removed.Alkali Silica Reaction (ASR): The reaction between the alkalis (sodium and potassium) in portland cement and certain siliceous rocks or minerals, such as opaline chert, strained quartz, and acidic volcanic glass, present in some aggregates. ICRI
16、 Bleed Water: Water within or emerging from newly placed concrete or mortar.Broadcast Flooring: Unfilled resins (commonly) or aggregate-filled slurries into which aggregate is scattered by a seeder or manually into the wet uncured resin or slurry which then cures with the aggregate embedded in it.Br
17、oadcast to Saturation/Excess: The process of scat-tering aggregate into a wet matrix (see Broadcast) until no matrix wetness is observed (until no more aggregate can be embedded into the wet matrix).Capillary: A microscopic channel on cured concrete that permits the movement of liquid water.Carbamat
18、e: A salt or an ester of carbamic acid. Carba-mates are formed by the reaction of an amine with carbon dioxide (R2NCO2H) and are associated with the “amine blush.” Carbonation: The reaction between carbon dioxide and a hydroxide or oxide to form a carbonate, especially in cement paste, mortar, or co
19、ncrete. Carbonate: A breakdown product of cement exposed to carbon dioxide and hydroxide or oxide. The molecular struc-ture is the simplest oxocarbon anion. It consists of one carbon atom surrounded by three oxygen atoms (CO3-2) in a trigonal planar arrangement.Hydration (of Cement): The reaction of
20、 water with the calcium silicate, aluminate, or aluminoferrite components of fine Portland cement grains necessary for the setting and densifying of concrete.Keyed (Key-in): The process by which cured concrete is removed to create a termination border for a fluid-applied flooring system.Lap Length:
21、The length of overlapping steel reinforcing bars.MVE (Moisture Vapor Emissions): Description of the moisture vapor that leaves the concrete slab.MVER (Moisture Vapor Emission Rate): Measurement of moisture vapor leaving a concrete slab. MVT (Moisture Vapor Transmission): Description of moisture vapo
22、r that passes through a membrane.MVTR (Moisture Vapor Transmission Rate): Rate of movement of moisture vapor through a membrane.Planarity: General evenness of a surface in an intended direction; may be a sloped or level area. Pozzolan: A siliceous or siliceous and aluminous mate-rial that in itself
23、possesses little or no cementitious value but that will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary tempera-tures to form compounds having cementitious properties; there are both natural and artificial pozzolans. ACIRecoat Window (Time
24、): A period beginning at a point when a coating has dried or cured sufficiently to be re-coated and ending when the coating has reached a degree of cure that re-coating is not recommended without an additional surface preparation procedure such as the application of a bond coat or abrading the surfa
25、ce.Resin: General term applied to a wide variety of more or less transparent and fusible products, which may be natural or synthetic. They may vary widely in color. Higher molecular weight synthetic resins are more generally referred to as poly-mers. In a broad sense, this term is used to designate
26、any polymer that is a basic binder material for coatings and plas-tics. Painting/Coatings DictionarySelf-Leveling Flooring: Resinous or polymer cementi-tious materials that flow out over a concrete slab to seek their own levels; they usually require termination strips rather than key-in terminations
27、. SSPC-Guide 20May 5, 20143Skim Coat: A thin layer of resin- or cement-based mortar used to smooth surface irregularities. Sloping Correction: 1) An adjustment applied to a distance measured on a slope to reduce it to a horizontal distance between the vertical lines through its end points. 2) The pr
28、ocess of installing a given pitch to a surface.Slump: A measure of the consistency of freshly mixed concrete, mortar, or stucco equal to the subsidence measured to the nearest 1/4 inch (6 mm) of the molded specimen imme-diately after removal of the slump cone. ACISlurry Flooring: An aggregate, powde
29、r, filler, resin mix producing a flowable, but not necessarily self-leveling mixture. Slurry floor materials are usually troweled to the thickness of the largest aggregate in the material.Soluble Alkali Ions: Substances that form charged hydroxide bases that dissolve in water.Spalling: The chipping
30、or fragmenting of a surface or surface coating caused, for example, by differential thermal expansion, contraction, or physical abrasion.Tie-In: In an installation sequence, the joining of additional material to material already placed.4. Design Considerations for Resinous Flooring SystemsThe succes
31、sful design, installation, and performance of a resinous flooring system depends on an evaluation of the existing surface conditions, the conditions of installation and the conditions of use. Each of these considerations will impact the selection of the surfacing system.4.1 Background Information on
32、 Concrete and Concrete Placement: Proper design and placement of the underlying concrete are essential to the proper performance of any resinous surfacing system. Detailed concrete and concrete substrate requirements are discussed at length by ACI 302.2R, ACI 364.1R, ACI 201.2R, ACI 546R; ICRI Guide
33、lines No. 310.1R, No. 320.1R and No. 310.2; and The Fundamentals of Cleaning and Coating Concrete, as well as a host of other standards and publications.Concrete is mainly a mixture of Portland cement, water, and mineral aggregate, usually sand and gravel. Sometimes additives such as fly ash and poz
34、zolans are used. The mixture cures and hardens by hydration. Water in the mix combines chemically with the cement to bind the aggregate into the rigid mass known as concrete. Although properly formulated and cured concrete is strong and rigid, it can be attacked both physically and chemically. Concr
35、ete is very strong in compres-sion but relatively weak in tension. It can and often does crack. Concrete is also fairly porous and subject to osmotic and capil-lary forces that absorb and release water. Absorbed water can freeze within the concrete and cause spalling and cracking.Strength-gain, wear
36、-resistance, and shrinkage properties of every concrete mix design are affected by the water-to-cement (w/c) ratio, normally expressed as the weight of mixing water per weight of cement. Concrete with a lower water-cement ratio gains more strength than concrete with a higher one, but such low ratios
37、 may be difficult to place and consoli-date properly because of the stiffness of the mix. Chemical admixtures (water reducers) are often used to increase work-ability of the concrete while keeping the water-cement ratio low. High water-cement ratios increase shrinkage cracking and reduce surface wea
38、r resistance and compressive strength.Approximately 200 grams of water for each 1 kilogram kg (0.20 pounds lb of water for each 1 lb) of cement is required for complete cement hydration. Roughly twice that ratio, or 400 grams of water for each 1 kg (0.40 lb of water per each 1 lb) of cement, is requ
39、ired for mixing, because additional water is absorbed on gel pore surfaces and the cement particles should all be wetted. More water may be added to enhance work-ability when placing concrete, but any amount in excess of 180 grams of water for each 1 kg (0.40 lb per 1 lb) of cement is not required f
40、or the hydration process and may eventually leave the concrete via evaporation or as bleed water. The general mix design shown in Table 1 is an example of a mixture that will yield a suitable substrate. An excess of water increases shrinkage and contributes to the formation of cracks and continuous
41、capillaries in the hardened concrete paste. The capillaries become channels for moisture movement and for intrusive and harmful chemical solutions after the cured concrete is placed in service. Wet curing will minimize development of capillary channels. TABLE 1EXAMPLE OF GENERAL MIX DESIGNCementitio
42、us Content (minimum)517 lbs/cubic yard (179.3 kg/m3)Water-Cement Ratio (by weight) 0.40-0.45Maximum Coarse Aggregate Size38 millimeters mm (1-1/2 inches)Air content 4-6%Slump (without high range water reducers)less than 76 mm (3 inches)Slump (with high range water reducers)150 to 230 mm (6-9 inches)
43、Compressive Strength (28 days)35 megapascals (MPa) (5,000 pounds per square inch psi)Permeability lowCement options -Water -SSPC-Guide 20May 5, 201444.2 Designing Concrete Surfaces for Resinous Floor Systems: While concrete slabs should be placed in accor-dance with standard ACI practices, it is equ
44、ally important that the concrete be designed to accommodate the intended end use. The tensile strength of a concrete substrate is impor-tant in concrete design. The tensile strength of concrete is approximately 10% of its compressive strength. The failure of a concrete substrate due to low tensile s
45、trength can result in a failure of any flooring or surfacing applied over it. Resinous flooring materials manufacturers generally recommend the minimum tensile strength of the concrete substrate to be 1.4 MPa (200 psi), but prefer tensile strength to be 2.4 MPa (350 psi) or greater as measured per A
46、STM D7234.An effective concrete substrate should also be low in permeability and high in density. Water or liquid moves through concrete through small pores, or capillaries, in the form of vapor; always from an environment of high vapor pressure to low vapor pressure. Vapor pressure combines the eff
47、ects of temperature and humidity. In general, moisture migrates from warm, humid conditions to cool dry conditions. It is the move-ment of moisture vapor within the slabnot the total quantity of moisture within the slabthat creates subsequent problems with non-permeable floor surfacings. Excess resi
48、dual or free water not used in the hydration process of cement will continue to migrate out of the concrete until the moisture content of the cement reaches equilibrium with its environment. If the envi-ronment below a concrete slab is continuously wet, capillary action will pull liquid from below t
49、he slab into the slab, but moisture most frequently moves in concrete as a vapor driven by the differential in vapor pressure. As vapor is driven through the concrete, soluble alkali ions are transmitted with it and collect at the surface. When mois-ture cycles back into the slab, concentrating the ionic solution, crystals can form which can create enough force to disbond a resinous surfacing. If undetected, the combined phenomena of MVER (see Section 5.5.1) and ASR (see Section 5.3 ) will generally result in bond failure when concrete is used as a substrate ove
