1、Designation: C 1608 07Standard Test Method forChemical Shrinkage of Hydraulic Cement Paste1This standard is issued under the fixed designation C 1608; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method measures the internal (absolute) vol-ume change of hydraulic cement paste that results from thehydration of the cementi
3、tious materials. This volume change isknown as chemical shrinkage.1.1.1 Procedure A, volumetric method.1.1.2 Procedure B, the density method.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated
4、 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. (WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue u
5、pon prolonged exposure.2)2. Referenced Documents2.1 ASTM Standards:3C 186 Test Method for Heat of Hydration of HydraulicCementC 188 Test Method for Density of Hydraulic CementC 219 Terminology Relating to Hydraulic CementC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of P
6、lastic ConsistencyC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC 1005 Specification for Reference Mass
7、es and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic Cements3. Terminology3.1 Definitions:3.1.1 chemical shrinkage, nthe absolute (internal) vol-ume change accompanying the hydration of cement, due to thefact that the cement hydration products occupy less physica
8、lvolume than the reactants.3.1.2 All other terms are as defined in Terminology C 219.4. Significance and UseNumerous properties of cementitious materials are con-trolled by their initial hydration rate. Examples include early-age strength development, heat release, and crack resistance.One direct an
9、d convenient measure of this initial hydration rateis provided by the measurement of the chemical shrinkage ofthe cement paste during its hydration. As cement hydrates, thehydration products occupy less volume than the initial reactingmaterials (cement and water). Due to this volume change, ahydrati
10、ng cement paste will sorb water from its immediatesurroundings, when available.At early times, this sorption is indirect proportion to the amount of hydration that has occurred.4This method is based on the one developed by Geiker.5Theresults are relevant to understanding the hydration behavior ofcem
11、ents. This method does not measure the bulk volumechanges (autogenous shrinkage) associated with chemicalshrinkage nor the cracking potential of concretes producedwith the evaluated cement.5. Apparatus5.1 Devices for Determining Mass, conforming to the re-quirements of Specification C 1005 and evalu
12、ated for precisionand accuracy at a total load of 100 g.5.2 Constant Temperature Water Batha water bath ca-pable of maintaining a temperature of 23.0 6 0.5 C, with a1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.31 on V
13、olume Change.Current edition approved June 15, 2007. Published July 2007. Originallyapproved in 2005. Last previous edition approved in 2006 as C 1608 06.2See the section on Safety, Manual of Cement Testing, Annual Book of ASTMStandards, Vol. 04.01.3For referenced ASTM standards, visit the ASTM webs
14、ite, 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.4L.J. Parrott, M. Geiker, W.A. Gutteridge, and D. Killoh, “Monitoring PortlandCement Hydration: Comparison of Me
15、thods,” Cement and Concrete Research, Vol.20, 919-926, 1990.5M. Geiker, “Studies of Portland Cement Hydration: Measurements of ChemicalShrinkage and a Systematic Evaluation of Hydration Curves by Means of theDispersion Model,” Ph.D. Thesis, Technical University of Denmark, Copenhagen,Denmark, 1983.1
16、*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sufficient capacity to hold the specimens being evaluated. Toavoid evaporative cooling, the surface of the water in the
17、bathshall be covered with floating plastic balls or fitted with aninsulated lid.5.3 Timing DeviceClock that can measure time to thenearest minute.5.4 For procedure A5.4.1 Capillary TubeAgraduated glass capillary tube withgraduations of 0.01 mL or smaller, and typically a capacity of1.0 mL.5.4.2 Smal
18、l Glass Vials (e.g., 22-mm diameter and 55-mmheight) with Rubber Stoppers that fit tightly into the glass vialsand have a hole placed in each stopper with the graduatedcapillary tube inserted through the hole (as shown in Fig. 1).Fix the capillary tube in the stopper using a two-componentepoxy or ot
19、her suitable adhesive applied at the stoppers topand bottom surfaces.5.5 For Procedure B5.5.1 Density bottle, glass, capacity approximately 20 mlwith internally conical glass stopper as shown in Fig. 2.6. Reagents and Materials6.1 Paraffin oil.6.2 De-aerated water (prepared by boiling water and seal
20、ingit in a closed container before it has cooled.)7. Procedure7.1 Preparation of Cement PastePrepare the cement pastein accordance with the proportions and procedure described inTest Method C 186 (Note 1). The pastes shall be prepared in amixing room meeting the temperature and humidity require-ment
21、s outlined in Specification C511. Record to the nearestminute the time when the water first contacts the dry cementpowder.NOTE 1Other mixing procedures such as mixing in a Hobart mixer(see Practice C 305) or kneading by hand in a sealed plastic bag may beused. The standard paste mixture uses 150 g o
22、f cement and 60 ml of water(water-cement ratio of 0.40). Adjust the volume of paste mixed to matchthe mixing equipment used. Other water-cement ratios may be used aslong as they are stated in the test report; higher water-cement ratios mayproduce significant bleeding of the cement paste which will i
23、nfluence theresults (by changing the effective water-cement ratio, etc.); lower water-cement ratios may lead to difficulties in preparing a fully compacted,homogeneous paste for subsequent evaluation and self-desiccation mayoccur.7.2 Prepare a minimum of two replicate specimens asdescribed below for
24、 either Procedure A or Procedure B.7.3 Procedure A7.3.1 Determine the mass of each empty glass vial to thenearest 0.01 g.7.3.2 Carefully place the prepared cement paste into theglass vial to achieve a paste height between 5 mm and 10 mmin the vial. Consolidate the paste in the vial by tapping the vi
25、alon a laboratory countertop, or placing it on a vibrating table, orsome similar procedure.7.3.3 Determine the mass of each glass vial with the cementpaste to the nearest 0.01 g.7.3.4 Carefully, without disturbing the cement paste, addclean, de-aerated water to fill the glass vial to the top.7.3.5 P
26、lace the rubber stopper with the inserted capillarytube tightly into the glass vial. Be careful to avoid theentrapment of air bubbles when the bottom rubber stoppersurface encounters the water in the glass vial. As the rubberstopper is inserted, the water level in the graduated capillarytube will ri
27、se. Optimally, the water level should rise near to butnot beyond the top mark of the graduations on the capillarytube. If the water level is not near enough to the top mark,clean, de-aerated water can be added via the top of the capillaryFIG. 1 Illustration of One Experimental Setup for Monitoring C
28、hemical Shrinkage of Hydrating Cement Paste Using Procedure A.C1608072tube to achieve the desired initial water height. Once the rubberstopper has been fitted to the vial, the completed assembly shallbe handled only by the vial (not by the capillary tube) to avoidloosening of the rubber stopper whic
29、h will result in an apparentvolume change of the specimen.7.3.6 Place a drop of paraffin oil in the top of the graduatedcapillary tube to minimize water evaporation from the tubeduring the testing period.7.3.7 Place the prepared specimens in the constant tempera-ture water bath at 23 C such that the
30、 tops of the glass vials arejust above the water level in the bath. Maintain the temperatureof the laboratory at 23 6 2 C. Record the time and initial level(height) of water, to the nearest 0.0025 mL, in the capillarytubes.7.3.8 Periodically (every 30 min or every hour, as conve-nient) record the ti
31、me to the nearest minute and water level inthe capillary tubes to the nearest 0.0025 mL for a total periodof at least 24 h. After the first 8 h, the recording intervals canbe lengthened to8hormore to avoid taking readings duringthe night, as long as a 24 h reading is obtained the followingday. Be su
32、re to take a reading 1 h after the paste was first mixedto use as a zero point in all calculations (this allows time for thespecimen to achieve temperature equilibrium within the waterbath).7.4 Procedure B7.4.1 Determine the mass of each empty density bottle to thenearest 0.0001 g.7.4.2 Carefully pl
33、ace the prepared cement paste into thedensity bottle to achieve a paste height between 5 mm and 10mm in the bottle. Consolidate the paste in the bottle by tappingthe bottle on a laboratory countertop, or placing it on avibrating table or some similar procedure. Determine the massof the density bottl
34、e with the consolidated cement paste to thenearest 0.0001 g.7.4.3 Carefully, without disturbing the cement paste, addclean, de-aerated water to fill the bottle to the top.7.4.4 Place the stopper tightly into the bottle. Be careful toremove any entrapped air bubbles when the bottom of thestopper enco
35、unters the water in the bottle. Add clean, de-aerated water via the perforated stopper to fill the bottle andstopper to excess (leave a bead of water on the top of thestopper to overfill the capillary tube). The filled assembly shallbe handled only by the bottle (not by the stopper) to avoidloosenin
36、g the stopper, which will result in an apparent changein the specimen, and not with bare fingers (e.g., wear latexgloves) which will cause an increase in mass due to transfer ofoil.7.4.5 Remove the excess water from the top of the stopperusing absorbent paper, wiping quickly to avoid sucking waterou
37、t of the capillary tube.7.4.6 Immediately determine the mass of the density bottlefilled with water to the top of the capillary tube. Determine themass to the nearest 0.0001 g.7.4.7 Place the filled density bottles in the constant tempera-ture water bath at 23 C such that the tops of the stoppers ar
38、ejust above the water level in the bath.7.4.8 At 1 h after the paste was first mixed, remove thedensity bottle from the water bath and wipe dry, fill to excesswith water, remove the excess and determine the mass to thenearest 0.0001 g.7.4.9 Periodically (every 30 or 60 min, as convenient) for aperio
39、d of at least 24 h, remove the density bottle from the waterbath and wipe dry, fill to excess with water, remove the excessand determine the mass to the nearest 0.0001 g. After the firsteight hours, the recording intervals can be lengthened to8hormore to avoid taking readings during the night, as lo
40、ng as a 24h reading is obtained the following day.8. Calculation8.1 The chemical shrinkage is computed as the measuredmL of sorbed water per gram of cement in the paste specimen.The mass of cement powder in the vial is given by:Mcement5Mvial1paste Mvialempty!S1.0 1wcD(1)whereMcement= mass of cement
41、in the vial (g),Mvial+paste= mass of the glass vial with the added cementpaste (g),Mvialempty= mass of the empty vial (g),w/c = water-cement ratio by mass of the preparedpaste (e.g., 0.40) and a density of 1000kg/m3is assumed for water.8.2 Procedure A8.2.1 The chemical shrinkage per unit mass of cem
42、ent attime t is computed as:CSt! 5ht! h60min!#Mcement(2)whereCS(t) = chemical shrinkage at time t (mL/g cement) (Note2).h(t) = water level in capillary tube at time t (mL)NOTE 2If it is desired to report the chemical shrinkage per unitvolume of cement powder, the values from Eq 2 can be converted to
43、mL/mL cement using the density of the cement powder determined usingTest Method C 188.8.3 Procedure B8.3.1 The chemical shrinkage per unit mass of cement attime t is computed as:CSt! 5SMt! M60min!#McementD/rW (3)FIG. 2 Illustration of a Density Bottle for Use in Procedure B.C1608073where:CS(t) = che
44、mical shrinkage at time t (mL/g cement)M(t) = mass of filled density bottle at time t (g)rW = density of water (mL/g) (0.99754 at 23 C)9. Report9.1 Report the following:9.1.1 Date and time paste specimen is prepared;9.1.2 Cementitious material sources and names;9.1.3 Mixing and compaction procedure
45、employed andwater-cement ratio by mass;9.1.4 Mass of each empty vial and mass of each vial withcement paste;9.1.5 A table of the water level in each capillary tube or themass of each filled density bottle vs. time;9.1.6 Atable and/or plot of the chemical shrinkage per gramof cement (reported to the
46、nearest 0.0001 mL/g) vs. time.10. Precision and Bias10.1 PrecisionThe precision statements for this testmethod are listed in Table 1 and are based on the resultsobtained in an interlaboratory study described in ResearchReport C01-1010.610.2 BiasSince there is no accepted reference materialsuitable f
47、or determining the bias of this procedure, no state-ment on bias is made.11. Keywords11.1 chemical shrinkage; hydration.SUMMARY OF CHANGESCommittee C01 has identified the location of selected changes to this test method since the last issue,C 1608 06, that may impact the use of this test method. (Ap
48、proved June 15, 2007)(1) Revised 10.1 and added new Table 1.Committee C01 has identified the location of selected changes to this test method since the last issue,C 1608 05, that may impact the use of this test method. (Approved November 1, 2006)(1) Revised 7.3.4 and 7.4.3.ASTM International takes n
49、o 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 infringement 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 or for
