1、Standard Method of Test for Portland Cement Content of Hardened Hydraulic-Cement Concrete AASHTO Designation: T 178-15 ASTM Designation: C1084-10 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3c T 178-1 AASHTO St
2、andard Method of Test for Portland Cement Content of Hardened Hydraulic-Cement Concrete AASHTO Designation: T 178-15 ASTM Designation: C1084-10 1. SCOPE 1.1. This test method covers the determination of portland cement content of a sample of hardened hydraulic-cement concrete. 1.2. The values in SI
3、units are to be regarded as the standard. The values given in parentheses are provided for information purposes only. 1.3. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropr
4、iate safety and health practices and determine the applicability of regulatory limitations prior to use. Disposal of some or all of the chemicals used in this method may require adherence to EPA or other regulatory guidelines. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 92, Wire-Cloth Sieves fo
5、r Testing Purposes M 231, Weighing Devices Used in the Testing of Materials T 24M/T 24, Obtaining and Testing Drilled Cores and Sawed Beams of Concrete T 105, Chemical Analysis of Hydraulic Cement T 248, Reducing Samples of Aggregate to Testing Size 2.2. ASTM Standards: C670, Standard Practice for P
6、reparing Precision and Bias Statements for Test Methods for Construction Materials C823/C823M, Standard Practice for Examination and Sampling of Hardened Concrete in Constructions C856, Standard Practice for Petrographic Examination of Hardened Concrete D1193, Standard Specification for Reagent Wate
7、r E832, Standard Specification for Laboratory Filter Papers 3. SIGNIFICANCE AND USE 3.1. This test method consists of two independent procedures: an oxide-analysis procedure that consists of two subprocedures and an extraction procedure. Each procedure requires a substantial degree of chemical skill
8、 and relatively elaborate chemical instrumentation. Except for the 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 178-2 AASHTO influence of known interference, determined cement contents are nor
9、mally equal to, or slightly greater than, actual values except for the maleic acid procedure, where results can also be significantly low when the paste is carbonated (Note 1). Note 1With certain limitations, the procedure is also applicable for eliminating the combined content of portland cement an
10、d pozzolan or slag in concretes made with blended hydraulic cement and blends of portland cement with pozzolans and slags. The results of this test method when applied to concretes made with blended cements or pozzolans depend on the composition of the pozzolan, the age of the concrete, the extent o
11、f the reaction of the pozzolan, and the fact that this test method may determine only the portland cement component of a blended cement. The test method should be applied to the determination of the blended cement content or the pozzolanic content only by use of calibration concrete samples or other
12、 information. Earlier versions of this test method can provide useful information as detailed by Hime1and Minnick.24. INTERFERENCES 4.1. Many constituents of concrete may interfere with the analysis of the concrete for portland cement content. The following limited lists of materials have been provi
13、ded as a guide. The rocks, minerals, or mineral admixtures listed will interfere with the cement content determination to the extent of their solubility during the dissolution procedure used. The solubility of rocks, minerals, or mineral admixtures may depend on the fineness of the test sample, the
14、water/cement ratio of the concrete, the extent of hydration, and the age of the concrete (extended exposure of the high pH of the concrete may affect the solubility of some minerals). 4.2. Substances Affecting Calcium Oxide Subprocedure: 4.2.1. The following are soluble in even the cold dilute hydro
15、chloric acid of this procedure and will contribute a high bias to the cement content calculated from the soluble calcium oxide: limestone, marble, dolomitic limestone, calcareous sandstone, calcareous chert, and caliche-encrusted and calcite- or dolomite-coated rocks. 4.2.2. The following may be sol
16、uble depending on the age and pH of the concrete; whether the mineral present is glassy or crystalline, or weathered or strained; and the fineness of the minerals present, and, if soluble, will bias the cement content calculated from the soluble calcium oxide high depending on the calcium content of
17、 the minerals: weathered or altered plagioclase feldspar, caliche-encrusted rocks, altered volcanic rocks (with calcareous inclusions), and many other calcium containing rocks. 4.2.3. Every percent of soluble calcium oxide that is contributed by soluble aggregate or mineral admixtures will bias the
18、cement content high by approximately 1.6 percent. 4.2.4. Silica fume may lower the acid solubility of the sample and hence bias the result low. 4.3. Substances Affecting the Soluble Silica Subprocedure: 4.3.1. The following may be soluble depending on the age and pH of the concrete; whether the aggr
19、egate is glassy or crystalline, or weathered or strained; and the fineness of the minerals: chert, opal, chalcedony, glassy volcanic rock, strained quartz (highly strained), quartzite, cataclastic rocks (mylonite, phyllonite), gneiss, schist, metagraywacke, and many other soluble silicon-containing
20、rocks and minerals. 4.3.2. Every percent of soluble SiO2contributed by aggregate or mineral admixtures will bias the reported cement content high by approximately 4.7 percent. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violati
21、on of applicable law.TS-3c T 178-3 AASHTO 4.3.3. Silica fume may lower the acid solubility of the sample and hence bias the result low. If the digestion time or temperature are sufficient to digest all of the portland cement, the silica fume will also be solubilized and bias the calculated cement co
22、ntent high. 4.4. Substances Affecting the Maleic Acid Procedure: 4.4.1. The same substances that are soluble in the soluble calcium or the soluble silica subprocedures may be soluble in the maleic acid procedure. (See Sections 4.2.1, 4.2.2, and 4.3.1.) 4.4.2. Every 1 percent of the sample that is ag
23、gregate or mineral admixture dissolved by the maleic acid will bias the cement content high by 1 percent. 4.4.3. Carbonated cement paste may not be soluble in the maleic acid-methanol dissolution and thus may bias the cement content results low. 4.4.4. The unhydrated iron and aluminum phases of the
24、portland cement may not be soluble in the maleic acid and, if not soluble, will bias the cement content low. This may be significant at early ages and less significant at later ages. 5. APPARATUS 5.1. Choose the apparatus from applicable items given in T 105 and from the following: 5.1.1. Chipmunk (
25、jaw ore crusher). 5.1.2. Disk pulverizer. 5.1.3. Rotary mill (rotating puck). 5.1.4. Sieves, 300 um (No. 50), 1.18-mm (No.16), and 4.75-mm (No. 4). 5.1.5. Ice bath or electric cooling apparatus. 5.1.6. Steam bath. 5.1.7. Funnel, Buchner-type porcelain funnel. 5.1.8. Filter paper, Type II, Class F an
26、d Class G as described in ASTM E832. 5.1.9. Beakers, 1000 and 250 mL. 5.1.10. Magnetic stirrer, variable speed, with a TFE-fluorocarbon-coated magnetic stirring rod, or an overhead stirrer with a propeller. 5.1.11. Volumetric flask, 1000 mL and 500 mL. 5.1.12. Filtering flask, 2000 mL. 5.1.13. Vacuu
27、m pump. 5.1.14. Watch glass, 125 mm. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 178-4 AASHTO 6. REAGENT AND MATERIALS 6.1. Soluble Silica Subprocedure: 6.1.1. Hydrochloric AcidReagent grade,
28、 density 1.19 Mg/m3. 6.1.2. Hydrochloric Acid (1:3)Mix 300 mL of hydrochloric acid into 900 mL of water. 6.1.3. Hydrochloric Acid (1:9)Mix 100 mL of hydrochloric acid into 900 mL of water. 6.1.4. Sodium Hydroxide (10 g/L)Dissolve 5 g of reagent grade sodium hydroxide in 200 mL of water and dilute to
29、 500 mL. 6.1.5. Hydrofluoric Acid48 percent, reagent grade. 6.1.6. Sulfuric AcidDensity 1.84 Mg/m3, reagent grade. 6.2. Calcium Oxide SubprocedureUse reagent as required in T 105. 6.3. Maleic Acid Procedure: 6.3.1. Maleic AcidTechnical grade. 6.3.2. MethanolTechnical grade, anhydrous. 6.3.3. Maleic
30、Acid SolutionPrepare a fresh solution of 15 percent maleic acid in methanol by dissolving and diluting 180 + 1 g of maleic acid with methanol to a final solution volume of 1200 mL. Prepare this solution fresh daily. Care must be taken to use methanol only in well-ventilated areas, preferably under a
31、 hood, to avoid skin contact and breathing vapors. Disposal of the maleic acid/methanol solution shall be according to applicable regulations. 6.3.4. Fullers EarthA clay-like material consisting of a porous colloidal aluminum silicate. Its high absorptivity has been found very beneficial for decolor
32、izing and purifying materials. 6.4. WaterAll references to water shall be understood to mean reagent water Types I through IV of ASTM D1193. 7. SAMPLING 7.1. Choose the concrete sample in accordance with the purposes of the investigation (Note 2). Note 2A standard procedure for sampling hardened con
33、crete is given in ASTM C823/C823M and a standard procedure for obtaining cores is given in T 24M/T 24. 7.2. Both the sample for cement content and for density shall have a minimum length and diameter of four times the nominal maximum size of the aggregate (Note 3). Note 3A single concrete core taken
34、 through the entire depth of the concrete is ordinarily an appropriate sample. This sample may be sawed or split lengthwise to provide samples for cement content, density, and petrographic examination, provided that the length and thickness of the split samples for cement content and density meet th
35、e minimum size specified in Section 7.2. If the split sample would not meet the minimum size requirements, perform the density measurement first, and then crush the entire dry sample for cement content determination. The recommended mass of concrete for cement content determination is 4.5 kg (10 lb)
36、. This mass should be obtained from more than one core when the concrete depth is small and one core will not supply a mass of 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 178-5 AASHTO 4.5 kg
37、(10 lb). If the concrete sample did not have a mass of 4.5 kg (10 lb), it should be so stated in the final report for the cement content result. 7.3. For cement content determination, crush the sample to pass a 4.75-mm (No. 4) sieve, mix thoroughly, and obtain a representative subsample for analysis
38、 by coning and quartering or by riffle splitting as described in T 248. The subsample should have a mass of 0.45 kg (1 lb). 8. CEMENT CONTENT PROCEDURE 8.1. Oxide Analysis Procedure: 8.1.1. Crush or grind the subsample prepared as described in Section 7.3 using a chipmunk (jaw ore crusher), a disk p
39、ulverizer, or a rotary mill (rotating-puck) device, so that all of the material passes a 300-m (No. 50) sieve. To minimize production of very fine material, use several passes of the sample through the equipment, removing the portion passing the device before regrinding the remainder of the sample.
40、Thoroughly mix by coning ten times from one paper to another. 8.1.2. Dry the crushed and ground material in an oven at 105 to 115C (220 to 240F) for 3 h and retain the sample in a sealed container. 8.1.3. Subprocedure to Be Used: 8.1.3.1. The soluble silica subprocedure shall be performed in all cas
41、es except where a petrographic examination has indicated there are siliceous aggregates or mineral admixtures that will be soluble in cold hydrochloric acid. 8.1.3.2. The calcium oxide subprocedure shall also be employed unless the aggregate contains a significant amount of calcareous components. 8.
42、1.3.3. All analysis shall be done in triplicate and the average of the three values shall be used in calculating cement content. 8.1.4. Soluble Silica Subprocedure: 8.1.4.1. Introduce 100 mL of dilute hydrochloric acid (1:3) into each of three 250-mL beakers. Cool until within the range of 3 to 5C (
43、38 to 41F) using an ice bath or electric cooling apparatus. 8.1.4.2. Weigh a 2-g sample to 0.001 g and slowly, over a 1-min period, add it to the cold hydrochloric acid. Maintain the 3 to 5C (38 to 41F) temperature for a 5-min period, and stir the mixture either continuously or at least several time
44、s during this period (Note 4). Note 4Observation of the solution during the introduction of the sample may provide useful information. Considerable effervescence indicates a substantial amount of calcite or carbonated paste. Delayed effervescence suggests a dolomitic aggregate. Lack of effervescence
45、 suggests the applicability of the calcium oxide subprocedure. 8.1.4.3. Decant through a Buchner-type porcelain funnel fitted snugly with two disks of a quantitative filter paper for fine precipitate, Type II, Class G filter paper. Once the filtration has begun, take care so that the mat and accumul
46、ated residue do not dry completely until the filtration process is complete. Regulate the suction so as to maintain a rapid rate of dripping during the greater part of the filtration. Retain as much of the residue in the beaker as possible. Wash twice by decantation with hot water. Save the filtrate
47、. Transfer the filter paper from the funnel to the beaker containing the balance of the residue, being careful that no residue is lost. Add 75 mL of hot sodium hydroxide solution (10 g/L) to the residue while stirring, macerate the filter paper, and digest, 2016 by the American Association of State
48、Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 178-6 AASHTO covered, on a steam bath for 15 min. During the digestion, occasionally stir the mixture. Filter all solids, and wash twice with hot water until the filtrate is neutral to litm
49、us. Combine the filtrates. 8.1.4.4. The filtrate now contains the silica in the form of silicic acid, either in true solution or in suspension in the hydrochloric acid medium. To ensure analysis of only the soluble silica, refilter any filtrate that is cloudy. (Allowing the filtrate to stand overnight will usually permit suspended silica to settle.) The soluble silica may be analyzed by either (1) or (2). (1) Analysis of Soluble Silica by Conversion to Silicon Tetrafluoride with Hydrofluoric AcidIn the case where the aggregate of the origi
