1、Designation:C30511 Designation: C305 12American 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 immed
2、iately following the 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
3、 practice covers the mechanical mixing of hydraulic cement pastes and mortars of plastic consistency.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and hea
4、lth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing ofHydraulic Cements and ConcretesC778 Specification for Sand3.
5、Significance and Use3.1 This practice is intended for use in the mechanical mixing of pastes and mortars for the testing of hydraulic cements.4. Apparatus4.1 MixerThe mixer shall be an electrically driven mechanical mixer of the epicyclic type, which imparts both a planetaryand a revolving motion to
6、 the mixer paddle. The mixer shall have a minimum of two speeds, controlled by definite mechanicalmeans. (Rheostat adjustment of speed will not be acceptable.) The first, or slow speed shall revolve the paddle at a rate of 140 65 r/min, with a planetary motion of approximately 62 r/min. The second s
7、peed shall revolve the paddle at a rate of 285 6 10 r/min,with a planetary motion of approximately 125 r/min. The electric motor shall be at least 124 W (16 hp). The mixer shall be equippedwith either an adjustment screw which is an integral part of the mixer or a clearance adjustment bracket such a
8、s the one shownin Fig. 1 (Note 1) to provide clearance between the lower end of the paddle and the bottom of the bowl that is not greater than2.5 mm but not less than 0.8 mm (Note 2) when the bowl is in the mixing position.NOTE 1When the bracket is in the proper position beneath the motor housing, t
9、he 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 the sliding frame that holds the bowl. It is intended that the bracket be fastenedat the front housing connection by inserting replacement screws on an appropriate size
10、 upward through the opening in each lug and into the existingthreaded holes in the bottom of the motor housing. The original stops for the sliding frame are to be filed down if they prevent the frame from comingin contact with the adjustment screws.NOTE 2This is the approximate diameter of a grain o
11、f 20-30 sand as described in Specification C778.4.2 PaddleThe paddle shall be readily removable, made of stainless steel, and shall conform to the basic design shown in Fig.2. The dimensions of the paddle shall be such that when in the mixing position the paddle outline conforms to the contour of th
12、ebowl used with the mixer, and the clearance between corresponding points on the edge of the paddle and the side of the bowl inthe position of closest approach shall be approximately 4.0 mm but not less than 0.8 mm.4.3 Mixing BowlThe removable mixing bowl shall have a nominal capacity of 4.73 L, sha
13、ll be of the general shape andcomply with the limiting dimensions shown in Fig. 3, and shall be made of stainless steel. The bowl shall be so equipped that itwill be positively held in the mixing apparatus in a fixed position during the mixing procedure. There shall be provided a lid, madeof a nonab
14、sorbing material not attacked by the cement. , and shall be made of stainless steel. The bowl shall be so equipped thatit will be positively held in the mixing apparatus in a fixed position during the mixing procedure. Provide an enclosure around the1This practice is under the jurisdiction of ASTM C
15、ommittee C01 on Cement and is the direct responsibility of Subcommittee C01.22 on Workability .Current edition approved April 1, 2011. Published May 2011. Originally approved in 1953. Last previous edition approved in 2006 as C30506. DOI: 10.1520/C0305-11.Current edition approved July 1, 2012. Publi
16、shed July 2012. Originally approved in 1953. Last previous edition approved in 2011 as C305 - 11. DOI: 10.1520/C0305-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refe
17、r to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all ch
18、anges accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100
19、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.mixing bowl or a lid to minimize evaporation of water during periods of rest of the mixture. The enclosure or lid shall be madeof non-absorbing material that is resistant to deterioration from the alkaline environment of
20、 cement pastes and mortars.4.4 ScraperThe scraper shall consist of a semirigid rubber blade attached to a handle about 150 mm long. The blade shallbe about 75 mm long, 50 mm wide, and tapered to a thin edge about 2 mm thick.NOTE 3A kitchen tool known as a plate and bowl scraper conforms to these req
21、uirements.4.5 Supplementary ApparatusThe balances, weights, glass graduates, and any other supplementary apparatus used inmeasuring and preparing the mortar materials prior to mixing shall conform to the respective requirements for such apparatus asspecified in the method for the particular test for
22、 which the mortar is being prepared.5. Temperature and Humidity5.1 The temperature and the humidity of the room and the temperature of the mixing water shall be maintained as describedin Specification C511 (Section Requirements for Cement Mixing Rooms).5.2 The dry materials shall be within the tempe
23、rature range of the room.6. Materials, Proportioning, and Consistency6.1 The materials and their proportions and quantities shall conform to the requirements contained in the particular method forwhich the paste or mortar is being prepared.7. Procedure for Mixing Pastes7.1 Place the dry paddle and t
24、he dry bowl in the mixing position in the mixer. Then introduce the materials for a batch into thebowl and mix in the following manner:Plate and BushingsBrassScrews and NutsSteelAll Dimensions in mmFIG. 1 Clearance Adjustment BracketFIG. 2 PaddleC305 1227.1.1 Place all the mixing water in the bowl.7
25、.1.2 Add the cement to the water and allow 30 s for the absorption of the water.7.1.3 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 scrape down into the batch any paste that may have collected on sides of thebowl.7.1.5Start7.1.5 Sta
26、rt the mixer at medium speed (285 6 10 r/min) and mix for 60 s.8. Procedure for Mixing Mortars8.1 Place the dry paddle and the dry bowl in the mixing position in the mixer. Then introduce the materials for a batch into thebowl and mix in the following manner:8.1.1 Place all the mixing water in the b
27、owl.8.1.2 Add the cement to the water; then start the mixer and mix 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-s period, while mixing at slow speed.8.1.4 Stop the mixer, change to medium speed (285 6 10 r/min), and mix for 30 s.8.1.5Stop8.1.5 St
28、op 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 the bowl; then for the remainder of this interval, close the mixerenclosure or cover the bowl with the lid.8.1.6Finish8.1.6 Fini
29、sh by mixing for 60 s at medium speed (2856 10 r/min).8.1.7 In any case requiring a remixing interval, any mortar adhering to the side of the bowl shall be quickly scraped down intothe batch with the scraper prior to remixing.WarningThe clearances between the paddle and the bowl specified in this pr
30、actice are suitable when using mortar made withstandard sand as described in Specification C778. To permit the mixer to operate freely and to avoid serious damage to the paddleand bowl when coarser aggregates are used, it may be necessary to set the clearance adjustment bracket to provide greatercle
31、arances 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 has identified the location of selected chang
32、es to this standard since the last issue(C30506)(C305 11) that may impact the use of this standard. (Approved AprilJuly 1, 2011.) 2012)(1)Revised Section 5.FIG. 3 Mixing BowlC305 123Committee C01 has identified the location of selected changes to this practice since the last issue, C305991, that may
33、 impact the use of this practice. (Approved August 1, 2006)(1) Deleted current reference to Hobart N50A mixer because references to individual manufacturers are reserved for instanceswhere a single manufacturer supplies the referred equipment.C305 124(2) Revised 7.1.5.(3) Revised 8.1.5.(4) Revised 8
34、.1.6) Revised Section 4.3.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infrin
35、gement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard
36、 or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views
37、 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 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 125
