ESBD_404026_1742592103146_02. Specification No TxDOT 490-32-47327.pdf

TEXAS DEPARTMENT OF TRANSPORTATION

SPECIFICATION NO.

TxDOT 490-32-47327

DATED: FEBRUARY 2025

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Environmental Test Chamber

PUBLICATION

This specification is a product of the Texas Department of Transportation (TxDOT). This specification may not be sold for profit or monetary gain. If this document is altered in any way, the header and any and all references to TxDOT must be removed. TxDOT does not assume nor accept any liability when this specification is used in the procurement process by any other entity.

1. SCOPE: This specification is for the purchase of an Environmental Test Chamber capable of controlling temperature, humidity, and other conditions for water retention test.

2. DELIVERY LOCATION: The unit must be delivered to the Texas Department of Transportation Materials and Tests Division at 6230 E. Stassney Ln, Austin, TX 78744. The vendor must use the Burleson Road entrance to access the TxDOT Stassney Campus.

3. EQUIPMENT:

3.1. Equipment furnished must be the latest model in current production, as offered to commercial trade, and of quality workmanship and material. The vendor represents that all equipment offered will be new. Used, shopworn, demonstrator, prototype, re-manufactured, or discontinued models are not acceptable.

3.2. All parts not specifically mentioned which are necessary for the unit to be complete and ready for operation or which are normally furnished as standard equipment must be furnished by the vendor. All parts must conform in strength, quality, and workmanship to the accepted standard of the industry.

3.3. The chamber interior dimensions must be at least 31.5 inches x 31.5 inches x 37 inches.

3.4. The interior of the chamber must be made from high-grade stainless steel to provide durability and resistance to corrosion in a high-humidity environment.

3.5. The humidity system must utilize filtered water with specific resistance between 50,000 and 1,000,000 ohms/cm to prevent system damage.

3.6. The chamber must include built-in safety mechanisms such as over-temperature and low-water cutoffs to protect both the operator and the equipment during extended operation periods.

3.7. The chamber must be designed to provide consistent and accurate testing results in accordance with ASTM C156.

3.8. All required documentation, including technical manuals, warranty information, and calibration certificates, must be provided upon delivery.

3.9. The supplier must conduct on-site start-up and testing to ensure proper functioning of the system. The supplier must also verify system operation and provide a complete check-out.

3.10. Operator training, including setup, operation, and maintenance, must be provided as part of the installation process.

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3.11. Must meet all requirements of ASTM C156 for Standard Test Method for Water Loss Through Liquid Membrane-Forming Curing Compounds for Concrete (Attachment A).

4. CONTROL AND MONITORING:

4.1. The chamber must be equipped with a user-friendly touchscreen interface, providing easy access to temperature and humidity controls.

4.2. The chamber must include Ethernet and USB connectivity for data logging, automatic test scheduling, and ASTM C156-compliant testing.

4.3. The system must support continuous monitoring and real-time data capture during testing.

5. TEMPERATURE RANGE AND HUMIDITY CONTROL:

5.1. The chamber must be capable of maintaining temperatures from -40°C to +180°C, with a minimum cooling rate of 3°C per minute and a heating rate of 4°C per minute.

5.2. The chamber must maintain a temperature of 23°C ± 2°C (73.4°F ± 3.6°F) with temperature tolerances of less than ±0.5°C.

5.3. The humidity control system must maintain relative humidity at 50% ± 4%, with controllable humidity in the range of 10% RH to 98% RH and accuracy within

±3.0% RH.

6. INSTALLTION AND CALIBRATION:

Vendor must install unit(s) at the designated TxDOT site and ensure complete installation and calibration of the equipment, including providing all cables, hoses, brackets, and accessories necessary for complete and safe installation, connection to power and telecommunications sources, and diagnostic testing. Unit(s) must be fully operational.

TxDOT will execute all physical modifications to the installation site unless otherwise specified.

Vendor must notify TxDOT point of contact via telephone or email a minimum of ten working days prior to proposed installation date.

7. FACTORY TRAINED TECHNICIAN:

The vendor must provide the services of a competent factory-trained technician thoroughly trained in the use and operation of the unit to TxDOT for a minimum of 4-hour(s) instruction on safety, operation, and preventive maintenance of the unit. Services must be provided after the unit has been delivered and is ready for operation but prior to payment.

The training must take place on TxDOT's premises at a time and date mutually agreed upon by the vendor and TxDOT.

NOTE: Please include all installation, training, and freight charges in the unit price of the bid tab.

8. EXAMPLE MAKE/MODEL:

8.1. Thermotron Model SE-600-3-3

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8.2. Weisstechnik Model ENDH-21/40

8.3. Or in accordance with paragraph 2.01 Specification of the TxDOT Terms and Conditions.

9. DELIVERABLES:

9.1. Environmental Test Chamber

9.2. Installation and Calibration

9.3. Training

10. WARRANTY REQUIREMENTS:

10.1. MATERIAL WARRANTY: Materials provided under the contract must be in current production, as offered to commercial trade, and be of quality material. Used, shopworn, demonstrator, prototype, reconditioned, or discontinued materials are not acceptable. Materials must be warranted against material defects and defects in workmanship for a period of not less than 12 months and cover 100% parts and labor.

The warranty period must commence upon date of acceptance by TxDOT. If the manufacturer’s standard warranty period exceeds 12 months, then the standard warranty period must be in effect. The vendor must be responsible for the warranty.

The vendor must provide the designated TxDOT representative with all manufacturers’ warranty documents upon completion of service prior to leaving the job site.

11. VENDOR PERFORMANCE: Vendor performance will be monitored on a regular basis by TxDOT.

11.1. An unsatisfactory performance determination includes, but is not limited to:

11.1.1. Failure to deliver any portion of the equipment.

11.1.2. Any requirement not met as outlined in the equipment requirements determined by TxDOT.

NOTE: Unsatisfactory performance may result in a negative vendor performance report, or cancellation of the contract or both, in addition to any other rights, liquidated damages and remedies provided by the contract or allowed by law.

11.2. An exceptional performance determination includes, but is not limited to:

11.2.1. Deliverables made early upon TxDOT personnel request.

11.2.2. Product upgrade substitution suggested and accepted at no additional cost to TxDOT.

11.2.3. Vendor commended for exceptional customer service; exceptional service provided.

11.2.4. Provided technical assistance when not required.

Standard Test Method for Water Loss [from a Mortar Specimen] Through Liquid Membrane-Forming Curing Compounds for Concrete1

This standard is issued under the fixed designation C156; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the U.S. Department of Defense.

1. Scope*

1.1 This test method covers laboratory determination of the

ability of liquid membrane-forming compounds for curing concrete to reduce moisture loss from mortar specimens during the early hardening period as a measure of their applicability for curing concrete.

1.2 The values stated in SI units are to be regarded as

standard. No other units of measurement are included in this standard.

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 appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.

(Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.)2

1.4 This international standard was developed in accor-

dance with internationally recognized principles on standard-ization established in the Decision on Principles for the Development of International Standards, Guides and Recom-mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

2. Referenced Documents

2.1 ASTM Standards:3

C87 Test Method for Effect of Organic Impurities in Fine Aggregate on Strength of Mortar

C125 Terminology Relating to Concrete and Concrete Ag-gregates

C150 Specification for Portland Cement C230/C230M Specification for Flow Table for Use in Tests of Hydraulic Cement

C305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency

C778 Specification for Standard Sand D1475 Test Method for Density of Liquid Coatings, Inks, and Related Products

D1653 Test Methods for Water Vapor Transmission of Or-ganic Coating Films

D2369 Test Method for Volatile Content of Coatings E178 Practice for Dealing With Outlying Observations

3. Terminology

3.1 Definitions—For definitions of terms used in this test

method, refer to Terminology C125.

4. Significance and Use

4.1 The moisture retaining ability of a product as deter-

mined by this test method is used to assess the suitability of materials for contributing to an appropriate curing environment for concrete. The laboratory test method is used both in formulating and in specifying or qualifying curing products.

This test method gives the user a measure of the ability of tested curing materials to impede the escape of water from a hydraulic cement mortar. Since it is desirable to retain water in fresh concrete to promote the hydration process, failure of the product to minimize the escape of water may lead to loss of strength, cracking, shrinkage, or low abrasion resistance of the hardened concrete, or a combination thereof.

4.2 Many factors affect the laboratory test results. Test

results obtained may be highly variable as indicated by the precision statement. Critical factors include the precision of the control of the temperature, humidity and air circulation in the curing cabinet, preparation and sealing of the mortar specimens, the age and surface condition of the mortar speci-men when the curing product is applied, and the uniformity and quantity of application of the curing membrane.

5. Apparatus

5.1 Mechanical Mortar Mixer, as described in Practice

C305, or a larger size mixture operating on the same principle.

1 This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.22 on Materials Applied to New Concrete Surfaces.

Current edition approved Oct. 1, 2020. Published October 2020. Originally approved in 1940. Last previous edition approved in 2017 as C156 – 17. DOI:

10.1520/C0156-20.

2 Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol 04.02.

3 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.

*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

Mohammad Samani (Texas Department of Transportation) pursuant to License Agreement. No further reproductions authorized.

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Purchase of Environmental Test Chamber for Materials and Tests Division Specification No. TxDOT 490-32-47327

Solicitation No. 601440000047327 Attachment A

5.2 Flow Table, as described in Specification C230/C230M.

5.3 Molds shall be made of metal, glass, hard rubber, or

plastic, and shall be watertight and rigidly constructed to prevent distortion during molding of the specimens or handling of the mold containing fresh mortar. They shall have a minimum surface area of 12000 mm2, and a minimum depth of 19 mm. The top surface shall be round, square, or rectangular with length not more than twice the width. The top of the mold shall have a rim to provide a firm level surface to support the wood float and to facilitate the grooving and sealing steps of the procedure. The rim shall be parallel with the bottom surface of the mold.

NOTE 1—Take care to avoid use of an excessive amount of oil, grease, or mold release compound on molds, particularly along the top rim where sealing compound will be applied. Use of masking tape on the top rim during application of release compound to prevent contamination has been found expedient.

5.4 Spoon—A stainless steel serving spoon having a bowl

75 to 100 mm long and 50 to 75 mm wide for transferring the mortar from the mixing bowl to the mold.

5.5 Gloves, of rubber or plastic, to be worn while molding

the specimens.

5.6 Tamper, of a nonabsorptive, nonabrasive material such

as medium-hard rubber or seasoned oak rendered non-absorptive by immersion for 15 min in paraffin at 75 to 95°C.

The tamper shall be rectangular with a 25 by 50-mm cross section and it shall be a convenient length (150 to 300 mm).

5.7 Wood Float, approximately 75 by 280 by 20 mm thick.

NOTE 2—A commercial wood float equipped with a substantial handle can be readily reduced to these dimensions. The float shall be resurfaced or replaced when there is noticeable wear to the floating surface.

5.8 Brush, medium-soft bristle 50-mm paint brush to brush

the surface of the specimens prior to sealing.

5.9 Curing Cabinet, maintained at a temperature of 37.8 6

1.1°C and a relative humidity of 32 6 2 %. The curing cabinet shall be of a design that allows movement of conditioned air such that the solvent from the curing compound will be readily evaporated and eliminated from the system. Air flow over the specimens shall be adjusted to provide an evaporation rate of

2.0 to 3.4 g/h as measured by the procedure of Annex A1. The evaporation rate shall initially be measured for each position in the cabinet in which a specimen will be placed, and shall be verified annually and whenever any changes are made to the cabinet. The range of evaporation rates for all specimen positions in the test cabinet shall be reported.

5.10 Balance, having the capacity to determine the mass of

a filled specimen mold to the nearest 0.1 g or less.

5.11 Applicator—For spray application, any apparatus that

can be used to apply the curing compound uniformly and with minimum overspray is acceptable. For brush or roller application, use the equipment recommended by the curing compound manufacturer.

6. Materials

6.1 Portland Cement, conforming to the requirements for

Type I of Specification C150.

6.2 Graded Standard Sand, conforming to the requirements

of Specification C778.

6.3 Sealing Compound, that will not be affected by the

curing material and which effectively seals against moisture loss between the boundary of the specimen and the edge of the mold.

NOTE 3—Tissue embedding wax, readily available from scientific supply houses, is a convenient and reliable sealant.

7. Conditioning

7.1 The temperature of the room and of all materials when

used in this test shall be 23 6 2°C unless otherwise specified, and the room humidity shall be 50 6 10 %.

8. Number of Specimens

8.1 A set of three or more test specimens shall be made in

order to constitute a test of a given curing material.

NOTE 4—When more than one set of specimens is to be prepared, each set should be handled as a group throughout the preparation to make the elapsed time between molding and application of the curing product as uniform as possible. This may require mixing the mortar for each set separately.

8.2 For determining the quantity of curing compound to be

applied (MA) calculate the total top surface area of the specimen, including the seal and the rim of the mold in square millimetres using appropriate geometric formulae.

NOTE 5—The area (A) used in calculating the mass loss per unit area

(L) is calculated in 15.2 from the surface dimensions measured inside the seal of the specimen.

9. Proportioning and Mixing Mortar

9.1 Proportioning—Determine the sand content of the mor-

tar by adding dry sand to a cement paste having a water-cement ratio of 0.40 by weight, to produce a flow of 35 6 5 in 10 drops of the flow table, following the procedure described in Test Method C87. Discard the mix used to determine the proportion of sand to cement.

NOTE 6—The sand:cement ratio required varies with the source of the cement. A ratio of 2.5:1 is suggested as a starting point. Flow may be determined on a 3 to 4 kg batch of mortar which is conveniently mixed in the mixer described in Practice C305. The mixture used to establish the sand:cement ratio is discarded because it is thought that the age and mixing history of the mortar affect the final moisture loss results and must be controlled.

9.2 Mixing—Combine the components of the mortar in a

mortar-mixing machine to produce a homogeneous mortar not more than 6 min from the time the water and the cement are combined.

NOTE 7—A generally effective sequence is to add the cement to all of the water in the mixing bowl and allow it to stand for 30 s. Then, mix at low speed for 30 s and, without stopping the mixer, add the sand within 30 s and continue mixing for 1 min. Stop the mixer for 1 min. During the first 15 s, scrape down the sides of the bowl. Finish by mixing for an additional 1 min, and promptly begin molding the specimens.

10. Preparing Specimens

10.1 Thoroughly clean the molds before each use. Use of a

mold release is acceptable. Avoid its application to the top rim of the mold to prevent interference with sealing of the edge.

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10.2 Half fill the mold and spread the mortar with the back

of the spoon to create a layer of approximately uniform thickness. Tamp over the entire surface with one stroke of the 25 by 50 mm face of the tamper per 1000 mm2 of surface area rounded to the nearest integer. Place a second layer of mortar, sufficient in amount to slightly overfill the mold and tamp in a similar manner. Using the 25-mm wide by 150 to 300-mm long edge of the tamper, fill the indentations made by the tamping and level the surface by pressing down firmly with a series of contacts across the entire surface. Strike off the specimen level with the top of the mold using a wood float with one pass only, in the direction of the long axis of the specimen for rectangular molds, using a sawing motion of the float. Keep the 75-mm face of the float firmly in contact with the mortar and edges of the mold so that the float creates a uniformly dense surface free of voids and cracks.

10.3 Wipe the outside surfaces of the molds clean, and place

the specimens in the curing cabinet maintained at the condi-tions specified in 5.9. The specimens shall be level and not subject to vibration. The spacing between the individual specimens and between the specimens and the side walls of the cabinet shall be between 50 and 175 mm. Within these limits the spacing shall be the same for all specimens. Use dummy specimens to fill any empty spaces in the cabinet.

11. Surface Preparation and Edge Sealing

11.1 Remove the specimens from the cabinet upon disap-

pearance of the surface water and lightly brush the surface using just sufficient force to remove the laitance and glaze without scarifying the mortar surface. If surface water appears after brushing, return the specimen to the cabinet but immedi-ately remove the specimen upon the disappearance of the surface water brought to the surface by the brushing operation, and brush again. The mortar shall be free of surface water but shall not be dry below the surface. The proper surface condition will be attained when brushing does not bring free water to the surface, or produce smearing, and can be deter-mined by gently rubbing an area with the finger tip.

NOTE 8—The exposure time in the cabinet and the initial moisture loss that will result in the proper surface condition is characteristic of the curing cabinet used and other testing conditions related to the laboratory performing the test. Uniformity of test surface conditions may be maintained by setting an expected exposure time or initial moisture loss.

When any test condition is changed (sand, cement, and so forth), a new exposure time or initial moisture loss, or both, shall be determined.

11.2 Form a V-shaped groove approximately 3 mm deep and

not more than 3 mm wide between the edge of the mortar specimen and the mold. Fill the groove with the sealing compound. The sealing compound shall not extend more than 6 mm from the edge of the mold onto the surface of the specimen.

NOTE 9—To cut out the groove for sealing, the tip of a pointed trowel, a pointed spatula, a pointed triangular can opener, or a “hawksbill point” ground on the end of a spatula or knife blade have all been reported to be effective.

12. Application of Curing Materials

12.1 Determine the density of the curing compound, Dm, in

accordance with Test Method D1475.

12.2 Calculate the mass of the curing compound to be

applied, MA, to the nearest 0.1 g based on the specified application rate, the total surface area calculated in accordance with 8.2, and the density of the curing compound, Dm. If no rate is specified, apply the curing compound at the rate of

5.0 m2/L. The method of application shall be in accordance with the manufacturer’s recommendations.

12.3 Weigh the specimen to the nearest 0.1 g (M1); then

uniformly apply the curing compound at the specified rate of application. Application shall be made expeditiously to only one specimen at a time.

NOTE 10—It is desirable to use a spray booth or a laboratory hood to control overspray and solvent fumes especially for curing compounds that are sprayed. However, the velocity of air movement in the vicinity of the specimen must be kept at a minimum so as to prevent, as much as possible, significant loss of volatiles during spraying and before the final weighing. Spraying shall be accomplished with the minimum pressure and flow rate of air with which an acceptable spray pattern can be attained.

12.4 Determine the proper coverage by comparing the

initial mass of the specimen (M1), before applying the curing compound, to the mass after coating. The final mass shall equal the initial mass of the specimen plus the predetermined mass of the curing compound to be applied. This will necessitate frequent weighing of the specimen during application as full coverage is approached. In the case of brush application, proper coverage may be determined by weighing the container, brush, and curing compound before and after application of the compound to the specimen. Total time for application to each specimen shall not exceed 2 min. Weigh to the nearest 0.1 g (M2). If the final amount of curing compound applied differs from the calculated amount for the specified coverage by more than 10 %, the specimen shall be discarded.

NOTE 11—In previous versions of this test method, coverage was determined by weighing the application equipment and the curing compound before and after application to the specimen. Which method is more precise has not been established.

12.5 Return the specimens to the cabinet without delay.

NOTE 12—Unusual loss caused by a leaking mold or a faulty seal may be detected by weighing the specimens 3 to 4 h after application of the curing material. If one specimen has lost considerably more than the others, this specimen is probably faulty. If only three specimens are being tested, consider the test invalid (see 15.4).

13. Determination of Non-Volatile Content of Curing Compounds

13.1 Determine the proportion of non-volatile matter in the

curing compound (NV) in accordance with Test Method D2369.

14. Duration of Test

14.1 Specimens shall be stored in the test cabinet for 72 h, then removed, and weighed (M3). Other test times may be specified by the purchaser.

15. Calculation

15.1 Loss of Mass:

15.1.1 Calculate the loss of mass from each specimen in

grams as follows:

C156 − 20

Mohammad Samani (Texas Department of Transportation) pursuant to License Agreement. No further reproductions authorized.

ML 5 M11~NV 3 MA! 2 M3 (1)

where:

ML = mass loss of the specimen, g, M 1 = mass of the sealed specimen, g, NV = proportion of non-volatile matter in the curing compound, g, MA = mass of the curing compound applied, g, = M2 − M1, M2 = mass of the specimen immediately after applying curing compound, g, and

M3 = mass of specimen at the conclusion of the test, g.

15.2 Specimen Area:

15.2.1 Calculate the area of the specimen (A) in square

millimetres by measuring the dimensions of the surface from the inner edges of the seal to the nearest millimetre and applying the appropriate geometric formula.

15.3 For each specimen, calculate the mass loss per unit

area (L) in kg/m2 as:

L 5 10003 ML/A (2)

15.4 Rejection of Results:

15.4.1 In a set of three or more specimens, if the difference in moisture loss between the specimen having the greatest loss and that with the least loss exceeds 0.15 kg/m2, the test shall be repeated and the average taken as that of all specimens in the original and repeat tests. If, after the repeat test, it is deter-mined that the result on a single specimen, whether from the original or repeat test, meets the criteria for rejection as an outlier as given in Practice E178, such value shall be disre-garded and a new average calculated that does not include such outlying value.

16. Report

16.1 Report the following information for the materials

tested:

16.1.1 Manufacturer’s name, address, and brand

designation,

16.1.2 Type of curing material,

16.1.3 Manufacturer’s batch number,

16.1.4 Quantity of material represented by the sample,

16.1.5 Date sampled, and

16.1.6 Source of the sample.

16.2 Report the following information regarding the test:

16.2.1 Laboratory sample identification,

16.2.2 Surface area inside the seal and depth of mortar

specimens,

16.2.3 Brand of cement used,

16.2.4 Proportions of mortar by weight,

16.2.5 Method of application,

16.2.6 Duration of the test,

16.2.7 Range of evaporation rates of test cabinet,

16.2.8 Rate of application, and

16.2.9 Average loss of water per unit area.

17. Precision and Bias

17.1 Precision—Efforts to establish a more meaningful

measure of the precision of this test method continue. The previous version of this test method, containing some differ-ences in testing technique, contained a precision statement. The single-operator standard deviation was reported as 0.13 kg/m2 and the multilaboratory standard deviation as 0.30 kg/m2.4

17.2 Bias—Since there is no accepted reference material

suitable for determining the bias of this test method, no statement on bias is being made.

18. Keywords

18.1 concrete curing materials; liquid membrane-forming curing compounds; moisture retention by concrete curing materials

ANNEX

(Mandatory Information)

A1. STANDARDIZATION OF EVAPORATION RATE IN TEST CABINETS

A1.1 This procedure provides a means for measuring the rate of evaporation of water from a standard surface in order to characterize a controlled set of environmental conditions (temperature, humidity, air circulation) by providing a system which will lose water at a nearly constant rate for a period of time long enough to establish a characteristic rate. Comparison of results from different positions in the same cabinet can establish whether or not conditions are uniform throughout the cabinet. Comparisons between labs may help to rationalize differing results.

A1.2 Apparatus:

A1.2.1 Cup—A permeability cup, conforming to the speci-fications of Test Method D1653.

A1.2.2 Filter Paper—7 cm disks.

A1.2.3 Absorbent Filler—Absorbent cotton balls.

A1.2.4 Mold Cover—Stiff cardboard or sheet metal plate having the same dimensions as the top of the specimen mold, and having a 63 mm diameter hole in its center.

A1.2.5 Balance—Any balance having a capacity of 200 g or more and a sensitivity and accuracy of 0.01 g or less.

A1.3 Procedure:

4 See Test Method C156 – 80a, 1987 Annual Book of ASTM Standards, Vol 04.02.

C156 − 20

Mohammad Samani (Texas Department of Transportation) pursuant to License Agreement. No further reproductions authorized.

A1.3.1 Fill the permeability cup with the absorbent filler using three cotton balls pulled together to make a uniform sponge. Fill the cup with distilled water, lay a disk of filter paper over the cup, and complete assembly of the cup. Place the mold cover on top of an empty specimen mold and fasten it in place with masking tape. Put the cup in the hole in the center of the mold. Place the mold and cup in the test cabinet in the position to be tested and allow 1 h for it to reach temperature equilibrium. Determine the mass of the cup to the nearest 0.01 g and immediately return it to the cabinet.

Reweigh at approximately 1 h intervals for 5 to 7 h. Record the mass and the total elapsed time to the nearest 2 min for each interval.

A1.4 Calculation:

A1.4.1 Calculate the total mass loss at each time interval as follows:

L 5 mi 2 mt (A1.1) where:

L = cumulative mass loss, mi = initial mass, and mt = mass at time, t.

A1.4.2 Plot the cumulative mass loss (L) versus elapsed time (t) and determine the slope for the test period. Report as loss rate in grams per hour. Alternatively, the slope may be calculated by a “least squares” method. (The rate of loss should be nearly constant throughout the test period.)

A1.5 Precision and Bias:

A1.5.1 Precision—Data for a precision statement is being collected.

A1.5.2 Bias—This test method has no bias because the evaporation rate is defined only in terms of this test method.

SUMMARY OF CHANGES

Committee C09 has identified the location of selected changes to this standard since the last issue (C156 – 17) that may impact the use of this standard. (Approved Oct. 1, 2020.)

(1) Added Terminology C125 to Referenced Documents. (2) Added new Section 3, Terminology.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.

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C156 − 20

Mohammad Samani (Texas Department of Transportation) pursuant to License Agreement. No further reproductions authorized.