1、Designation: C 398 98 (Reapproved 2008)Standard Practice for Use ofHydraulic Cement Mortars in Chemical-Resistant Masonry1This standard is issued under the fixed designation C 398; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice provides recommendations for use ofhydraulic cement mortars for chemical-resistant masonry con
3、-struction.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, i
4、f any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 144 Specification for Aggregate for Masonry
5、MortarC 150 Specification for Portland CementC 171 Specification for Sheet Materials for Curing ConcreteC 267 Test Methods for Chemical Resistance of Mortars,Grouts, and Monolithic Surfacings and Polymer ConcretesC 279 Specification for Chemical-Resistant Masonry UnitsC 309 Specification for Liquid
6、Membrane-Forming Com-pounds for Curing ConcreteC 404 Specification for Aggregates for Masonry GroutC 595 Specification for Blended Hydraulic CementsC 904 Terminology Relating to Chemical-Resistant Non-metallic MaterialsD 226 Specification for Asphalt-Saturated Organic FeltUsed in Roofing and Waterpr
7、oofingD 227 Specification for Coal-Tar-Saturated Organic FeltUsed in Roofing and Waterproofing3. Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice, see Terminology C 904.FLOORS AND CONSTRUCTION UNITS4. Preparation of Concrete Fill or Subbase4.1 In new construction, the surfac
8、e of the concrete fill shallbe free of mortar drippings, projecting joints, etc. Smoothsurfaces resulting from the use of plywood forms or a steeltrowel finish are not acceptable and must be given a coursesandpaper profile by blasting or mechanical scarifying. Thepreferred finish for new concrete fl
9、oors after leveling is a woodfloat finish, followed by a single pass metal trowel finish. Thecontour of the finished surface must be free of ridges anddepressions, cracks, or open joints. When an old concretesurface is to be removed, it shall be cut out to provide thenecessary thickness for the new
10、setting bed and the construc-tion unit. The surface must be clean, free of loose particles,hard, and roughened to ensure intimate bond with the new bedjoint. The edges around all cut-out sections shall be maintainedstraight and vertical. A final finishing of the edges by handchiseling may be necessa
11、ry.4.2 A cleavage membrane consisting of waterproof buildingfelt as specified in Specifications D 226 and D 227, or poly-ethylene sheeting 0.004 in. (0.10 mm) thick is generally usedover wood frame construction and is preferred for many othertypes of construction. It may be omitted over certain type
12、s ofconcrete bases of limited areas. Cleavage membrane shall haveedges overlapped a nominal 2-in.4.3 CleaningAll dirt, dust, loose particles, surfacelaitance, and debris shall be removed from the concrete fill orsubbase by vigorous brooming, vacuuming, or other means.The surface must be free of grea
13、se, oil, or wax deposits.4.4 Screed StripsWood or metal strips shall be used togage the thickness of the setting bed.4.5 Thickness of Setting BedThe setting bed shall be 1 to112 in. (25 to 38 mm) thick.4.6 Wetting Concrete Fill or SubbaseSeveral hours beforeplacing the setting bed, the prepared conc
14、rete surface shall bethoroughly saturated with clean water. About 1 h beforeplacing the topping, all surface water shall be removed with amop or by other means.NOTE 1The procedure described in this paragraph does not apply tofloors installed over a cleavage membrane.1This practice is under the juris
15、diction of ASTM Committee C03 on Chemical-Resistant Nonmetallic Materials and is the direct responsibility of SubcommitteeC03.02 on Monolithics, Grouts and Polymer Concretes.Current edition approved June 1, 2008. Published July 2008. Originally approvedin 1957. Last previous edition approved in 2003
16、 as C 398 98 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr H
17、arbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.7 Expansion JointsWhen required, the expansion jointstrips shall be located and set in position. If the expansionjoints are not of the preset type, removable strips shall be set soas to keep the joints free of dirt and morta
18、r.5. Cement Paste Slush Coat5.1 About 15 min before placing the setting bed, theconcrete slab surface shall be given a slush coat of grout. Thegrout shall consist of either neat cement and water, or cement,sand, and water. The slush coat shall not be spread over such alarge area that it will dry out
19、 before the setting bed is placed tocover it. The consistency of the slush coat shall be similar tothat of thick cream, and its thickness shall not exceed116 in.(1.6 mm).NOTE 2The procedure described in this section does not apply tofloors installed over a cleavage membrane.6. Materials and Manufact
20、ure6.1 Portland and Portland Blast-Furnace Slag CementsSee Specifications C 150 and C 595. No calcium aluminatecement, lime, or admixture shall be mixed with these cements,in the mortar batch or in the mixing water.6.2 Calcium Aluminate CementNo portland or portlandblast-furnace slag cements, lime,
21、or admixture shall be mixedwith this cement, in the mortar batch or in the mixing water.6.3 AggregateThe aggregate shall be in accordance withSpecification C 144 or C 404, or both.6.4 BrickThese mortars may be used with masonry unitsof brick (clay or shale) meeting the requirements of Specifi-cation
22、 C 279, and with tile masonry units. The brick shall beclean and protected from frost damage. Bricks shall be wettedseveral hours before laying, unless their gain in weightresulting from partial immersion flatwise in18 in. (3 mm) ofwater for 1 min is less than34 oz/30 in.2(0.11 g/cm2)ofimmersed area
23、. There shall be no free water on the bricks whenlaid.6.5 WaterThe mixing water shall be approximately neu-tral and shall be potable.6.6 Metal ReinforcingIf reinforcing is used, it shall bewelded wire fabric 2 by 2 in. (50 by 50 mm), and 16 by16-gage (0.65 by 0.65-mm), or expanded metal reinforcing
24、notless than 1.8 lb/yd2(1.0 kg/m2).6.7 Expansion JointsWhen required, expansion jointcompound or premolded joints shall be as specified.7. Proportions7.1 The setting bed shall consist of one bag of cement and3ft3(0.085 m3) of sand (Note 3). For ordinary groutingconditions, the grout shall contain on
25、e bag of cement and 2 ft3(0.057 m3) of sand (Note 3); but for thin joints where a finersand is used the mix shall consist of one bag of cement and notmore than 1 ft3(0.028 m3) of fine sand.NOTE 3Measurements of aggregate shall be in the damp, loosecondition.7.2 The water proportions may be determine
26、d as follows:For setting beds, only enough water shall be used to produce amoist surface after the setting bed has been placed and readyfor the tile or brick. Grouts to be squeegeed into joints shall beof the consistency of heavy cream. Pointing mortars shall be ofsuch consistency that when they are
27、 pressed into a vertical jointno slump of the mortar will occur.8. Mixing and Placing Setting Bed8.1 All equipment shall be clean and free of other cement,lime, plaster, etc., prior to use. Each batch shall be mixed eithermechanically or manually until uniform. The setting bed shallbe spread and scr
28、eeded until the surface is true and even inplane, either level or uniformly sloped for drainage, as speci-fied. As large an area as can be covered with the constructionunits before the mortar has reached its initial set shall be placedat one operation. When more setting mortar has been placedthan ca
29、n be covered, the unfinished portion shall be cut back toa clean, beveled edge, removed, and discarded. Any metalreinforcement shall be placed approximately in the center ofthe setting bed.9. Setting of Construction Units9.1 A thin layer of neat cement paste132 to116 in. (0.8 to1.6 mm) in thickness
30、shall be trowelled or brushed over thesetting bed. Neat cement paste132 in. thick may also beapplied to the bottom of each construction unit. The totalthickness of the layer of neat cement between the constructionunit, and the setting bed shall not exceed116 in. Do not laysetting bed far in advance
31、of setting construction unit, and in nocase set them on a dry bed. Set the construction unit, beforeinitial set has taken place. Beat the construction unit intocomplete and intimate contact with the plastic mortar. Set andlevel each construction unit immediately. Do not set large areasand then later
32、 level the construction units.10. Grouting Construction Units10.1 Grouting shall be done as soon as possible after theinitial set has taken place in the setting bed. Force the grout ormortar into the joints by troweling or some other suitablemethods to ensure a dense, void-free, flush finished joint
33、. Donot let excess mortar or mortar scum dry and set on faces ofconstruction units.As grouting progresses, strike excess mortarfrom joints and clean the faces of the construction units withclean burlap or sponges.11. Width of Joints11.1 Joints shall have a width of from14 to12 in. (6 to 13mm), depen
34、ding on the size of construction unit, in accordancewith the manufacturers recommendations.12. Curing12.1 It is essential that hydraulic cement mortar or groutjoints be properly cured to ensure maximum retention of themixing water. Improperly cured joints will result in soft, dustyjoints with low ph
35、ysical properties, that is, poor tensile,flexural, and adhesion to the construction units and substrate.Water is the most effective media for curing cementitious-typejoints. Acceptable methods for curing hydraulic cement mortaror grout joints are as follows:12.1.1 Ponding MethodDikes are set up as r
36、equired andsufficient water placed into the diked area.Atank or vessel mayC 398 98 (2008)2be filled with water. To prevent thermal stresses, the watershould not be more than 20F (11C) cooler than the mortar orgrout joints.12.1.2 Burlap MethodCover the surface to be cured withclean burlap or other su
37、itable material and keep wet by foggingwith water throughout the curing period. Cover material shouldbe free of sizing or foreign material that could discolor, attack,hasten, or retard the curing process. New burlap, prior to use,should be thoroughly soaked and rinsed in potable water toensure freed
38、om from contaminants.12.1.3 Vapor Barrier MethodThe surface to be curedshould be thoroughly wetted with spray or fog nozzles andcovered with an impermeable vapor barrier. Acceptable barri-ers are waterproof paper, polyethylene, and polyvinyl chloridefilms. In hot, dry atmospheres, periodic flooding
39、of the surfacebeneath the vapor barrier is required. White pigmented filmsshould be used in hot weather. All sheet materials mustconform to standard specifications for sheet materials forcuring concrete, in accordance with Specification C 171.12.1.4 Curing Compound MethodLiquid membrane-forming comp
40、ounds can be used as curing membranes. Thesematerials cure by retaining the water already present in themasonry components; that is, construction units, bed, andjoints. Curing compounds must be applied immediately fol-lowing installation of the construction unit surface in order toprevent loss of mo
41、isture due to evaporation. Sequence ofapplication is critical.All curing compounds should conform tothe requirements of standard specifications for liquidmembrane-forming compounds for curing concrete in accor-dance with Specification C 309.NOTE 4The use of liquid membrane-forming compounds could pr
42、e-vent adhesion of any subsequent surface treatments desired to be appliedover the construction unit surface.12.1.5 Attention to curing ensures high-early strength. Withcalcium aluminate cement, sufficient curing is attained at theend of 24 h and, with portland and portland blast-furnace slagcements
43、 at the end of seven days. The installation may beplaced in operation immediately following the cure period.WALLS, LININGS, CHIMNEYS, ETC.13. Materials and Manufacture13.1 Portland and Portland Blast-Furnace Slag CementsSee 6.1.13.2 Calcium Aluminate CementSee 6.2. If additionalworkability is needed
44、, from 3 to 5 lb (1.5 to 2.5 kg) of plasticfireclay may be added per bag of cement.13.3 AggregatesSee 6.3.13.4 BrickSee 6.4.13.5 WaterSee 6.5.14. Proportions14.1 The mortar shall consist of 1 bag of cement and notless than 212 ft3(0.07 m3) nor more than 312 ft3(0.1 m3)ofsand (Note 3). An average mor
45、tar is generally considered toconsist of one bag of cement and 3 ft3(0.085 m3) of aggregate,measured in the damp, loose condition. Only enough watershall be used to produce a moist surface prior to laying thebrick.15. Mixing Mortar and Laying Construction Units15.1 All equipment shall be clean and f
46、ree of other cement,lime, plaster, etc., prior to use. Each batch shall be mixed eithermechanically or manually until uniform. The amount of mortarmixed at one time shall not exceed the amount that the masoncan use within a period of 30 min. In most cases, the mortarjoints should have a width of38 i
47、n. (9 mm).15.2 Mortar shall be plastic, smooth, and workable. Periodicremixing of the mortar during use may be necessary tominimize stiffening.15.3 All bed and head joints shall be completely filled withmortar. Bed joints are satisfactorily filled by spreading a thickbed of mortar and making a shall
48、ow furrow. Filling head jointsshall be done by placing a heavy buttering of mortar on the endof the construction unit, pressing it down into the bed joint andpushing it into place so that the mortar squeezes out from thetop and sides of the head joint. Mortar shall correspondinglycover the side of t
49、he construction unit, before placing as aheader. The excess mortar squeezed from the joints shall bestruck even with the wall and tooled at the proper time toproduce a smooth concave joint. The construction units shallnot be moved after initial contact with the mortar. If out of line,remove the construction unit and relay.15.4 It is customary to lay the construction units 112 to 2 in.(37 to 50 mm) away from the structural substrate or wall.Spacing is maintained by the use of spacer blocks. After jointshave set, the space between the structu
