1、Designation: C305 13 American Association StateHighway and Transportation Officials StandardAASHTO No.: T162Standard Practice forMechanical Mixing of Hydraulic Cement Pastes and Mortarsof Plastic Consistency1This standard is issued under the fixed designation C305; the number immediately following t
2、he designation indicates the year oforiginal adoption or, in the case of revision, the 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. Scope*1.1 This practice covers t
3、he mechanical mixing of hydrauliccement pastes and mortars of plastic consistency.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wi
4、th 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:2C511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, a
5、nd Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC778 Specification for Sand3. Significance and Use3.1 This practice is intended for use in the mechanicalmixing of pastes and mortars for the testing of hydrauliccements.4. Apparatus4.1 MixerThe mixer shall be an electricall
6、y driven me-chanical mixer of the epicyclic type, which imparts both aplanetary and a revolving motion to the mixer paddle. Themixer shall have a minimum of two controlled speeds. (Rheo-stat adjustment of speed is not acceptable.) The first, or slowspeed shall revolve the paddle at a rate of 140 6 5
7、 r/min, witha planetary motion of approximately 62 r/min. The secondspeed shall revolve the paddle at a rate of 285 6 10 r/min, witha planetary motion of approximately 125 r/min. The electricmotor shall be at least 124 W (16 hp). The mixer shall beequipped with either an adjustment screw which is an
8、 integralpart of the mixer or a clearance adjustment bracket such as theone shown in Fig. 1 (Note 1) to provide clearance between thelower end of the paddle and the bottom of the bowl that is notgreater than 2.5 mm but not less than 0.8 mm (Note 2) whenthe bowl is in the mixing position.NOTE 1When t
9、he bracket is in the proper position beneath the motorhousing, the lugs are to the front and facing upward and the heads of theadjustment screws are to the rear and facing downward in the path of thesliding frame that holds the bowl. It is intended that the bracket befastened at the front housing co
10、nnection by inserting replacement screwson an appropriate size upward through the opening in each lug and into theexisting threaded holes in the bottom of the motor housing. The originalstops for the sliding frame are to be filed down if they prevent the framefrom coming in contact with the adjustme
11、nt screws.NOTE 2This is the approximate diameter of a grain of 20 to 30 sandas described in Specification C778.4.2 PaddleThe paddle shall be readily removable, madeof stainless steel, and shall conform to the basic design shownin Fig. 2. The dimensions of the paddle shall be such that whenin the mix
12、ing position the paddle outline conforms to thecontour of the bowl used with the mixer, and the clearancebetween corresponding points on the edge of the paddle and theside of the bowl in the position of closest approach shall beapproximately 4.0 mm but not less than 0.8 mm.4.3 Mixing BowlThe removab
13、le mixing bowl shall have anominal capacity of 4.73 L, shall be of the general shape andcomply with the limiting dimensions shown in Fig. 3, and shallbe made of stainless steel. The bowl shall be so equipped thatit will be positively held in the mixing apparatus in a fixedposition during the mixing
14、procedure. Provide an enclosurearound the mixing bowl or a lid to minimize evaporation ofwater during periods of rest of the mixture. The enclosure or lidshall be made of non-absorbing material that is resistant todeterioration from the alkaline environment of cement pastesand mortars.1This practice
15、 is under the jurisdiction ofASTM Committee C01 on Cement andis the direct responsibility of Subcommittee C01.22 on Workability.Current edition approved June 1, 2013. Published July 2013. Originally approvedin 1953. Last previous edition approved in 2012 as C305 - 12. DOI: 10.1520/C0305-13.2For refe
16、renced 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.*A Summary of Changes section appears at the end of this standardCopyr
17、ight ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.4 ScraperThe scraper shall consist of a semirigid rubberblade attached to a handle about 150 mm long. The blade shallbe about 75 mm long, 50 mm wide, and tapered to a thin edgeabout 2 mm th
18、ick.NOTE 3A kitchen tool known as a plate and bowl scraper conforms tothese requirements.4.5 Supplementary ApparatusThe balances, weights,glass graduates, and any other supplementary apparatus used inmeasuring and preparing the mortar materials prior to mixingshall conform to the respective requirem
19、ents for such apparatusas specified in the method for the particular test for which themortar is being prepared.5. Temperature and Humidity5.1 The temperature and the humidity of the room and thetemperature of the mixing water shall be maintained asdescribed in Specification C511 (Section Requiremen
20、ts forCement Mixing Rooms).5.2 The dry materials shall be within the temperature rangeof the room.6. Materials, Proportioning, and Consistency6.1 The materials and their proportions and quantities shallconform to the requirements contained in the particular methodfor which the paste or mortar is bei
21、ng prepared.7. Procedure for Mixing Pastes7.1 Place the dry paddle and the dry bowl in the mixingposition in the mixer. Then introduce the materials for a batchinto the bowl and mix in the following manner:7.1.1 Place all the mixing water in the bowl.7.1.2 Add the cement to the water and allow 30 s
22、for theabsorption of the water.Plate and BushingsBrassScrews and NutsSteelAll Dimensions in mmFIG. 1 Clearance Adjustment BracketFIG. 2 PaddleFIG. 3 Mixing BowlC305 1327.1.3 Start the mixer and mix at slow speed (140 6 5 r/min)for 30 s.7.1.4 Stop the mixer for 15 s and during this time scrapedown in
23、to the batch any paste that may have collected on sidesof the bowl.7.1.5 Start the mixer at medium speed (285 6 10 r/min) andmix for 60 s.8. Procedure for Mixing Mortars8.1 Place the dry paddle and the dry bowl in the mixingposition in the mixer. Then introduce the materials for a batchinto the bowl
24、 and mix in the following manner:8.1.1 Place all the mixing water in the bowl.8.1.2 Add the cement to the water; then start the mixer andmix at the slow speed (140 6 5 r/min) for 30 s.8.1.3 Add the entire quantity of sand slowly over a 30-speriod, while mixing at slow speed.8.1.4 Stop the mixer, cha
25、nge to medium speed (285 6 10r/min), and mix for 30 s.8.1.5 Stop the mixer and let the mortar stand for 90 s.During the first 15 s of this interval, quickly scrape down intothe batch any mortar that may have collected on the side of thebowl; then for the remainder of this interval, close the mixeren
26、closure or cover the bowl with the lid.8.1.6 Finish by mixing for 60 s at medium speed (2856 10r/min).8.1.7 In any case requiring a remixing interval, any mortaradhering to the side of the bowl shall be quickly scraped downinto the batch with the scraper prior to remixing.WarningThe clearances betwe
27、en the paddle and the bowlspecified in this practice are suitable when using mortar madewith standard sand as described in Specification C778.Topermit the mixer to operate freely and to avoid serious damageto the paddle and bowl when coarser aggregates are used, itmay be necessary to set the clearan
28、ce adjustment bracket toprovide greater clearances than those specified in 4.1.For additional useful information on details of cement test methods, reference may be made to the “Manual of CementTesting,” which appears in the Annual Book of ASTM Standards, Vol 04.01.SUMMARY OF CHANGESCommittee C01 ha
29、s identified the location of selected changes to this standard since the last issue (C305 12)that may impact the use of this standard. (Approved June 1, 2013)(1) Revised 4.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mention
30、edin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and
31、 must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of
32、 theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
33、C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C305 133
