1、Standard Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes AASHTO Designation: M 201-15 ASTM Designation: C511-13 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W.
2、, Suite 249 Washington, D.C. 20001 TS-3a M 201-1 AASHTO Standard Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes AASHTO Designation: M 201-15 ASTM Designation: C511-13 1. SCOPE 1.1. This specification include
3、s requirements for mixing rooms, where paste and mortar specimens are prepared, and for moist cabinets, moist rooms, and water storage tanks, where paste, mortar, and concrete test specimens are stored. 1.2. The values stated in SI units are to be regarded as standard. No other units of measurement
4、are included in this standard. Values in SI units shall be obtained by measurement in SI units or by appropriate conversion, using the Rules for Conversion and rounding given in Standard IEEE/ASTM SI 10, of measurements made in other units. 1.3. This standard does not purport to address all of the s
5、afety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. ASTM Standards: C51, Standard Terminology R
6、elating to Lime and Limestone (as used by the Industry) E77, Standard Test Method for Inspection and Verification of Thermometers 2.2. IEEE/ASTM Standard: SI10, American National Standard for Metric Practice 3. TERMINOLOGY 3.1. Definitions: 3.1.1. mixing room, na room with controlled temperature and
7、 relative humidity where cement paste and mortar specimens are prepared. 3.1.2. moist cabinet, na compartmented storage facility of moderate dimensions with controlled temperature and relative humidity. 3.1.3. moist room, na walk-in storage facility with controlled temperature and relative humidity,
8、 commonly called a “fog room” when the prescribed relative humidity is achieved by the atomization of water. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a M 201-2 AASHTO 4. REQUIREMENTS FOR CEMEN
9、T MIXING ROOMS 4.1. The temperature of the air in the vicinity of the mixing slab, molds, and baseplates shall be maintained at 23.0 4.0C and at a relative humidity of not less than 50 percent. 4.2. The temperature of the mixing water used to prepare cement paste and mortar specimens shall be 23.0 2
10、.0C. 5. TEMPERATURE MEASURING DEVICES 5.1. Reference Temperature Measuring DevicesUsed to verify the temperature recorder, must be accurate and readable to 0.5C. A copy of the certificate or report that verifies the accuracy shall be available in the laboratory. Note 1The ice-point method described
11、in ASTM E77 may be used to ensure that no damage to the reference thermometer has occurred during shipping. 5.2. Temperature RecorderShall record temperatures every 15 min or less and shall be accurate and readable to 1C. The data from the recorder shall be evaluated at a minimum of once each week.
12、A record of this evaluation documenting the date checked, a confirmation that the data are within the required temperature range, and the name of the individual performing this evaluation shall be maintained in the laboratory. (See Note 2.) Note 2This requirement may be satisfied by an initialed and
13、 dated temperature recorder chart. Brief changes in the temperature due to door openings should be ignored. 5.2.1. The temperature recorder shall be verified at least every 6 months or whenever there is a question of accuracy. 5.2.1.1. For moist cabinets and rooms, position the reference temperature
14、 measuring device in a readable position in air as near as practical to the temperature recorder probe. Keep the door closed for at least 5 min prior to taking readings. Record the temperature readings of both the temperature recorder and the reference temperature measuring device. When taking these
15、 readings, the reference temperature measuring device shall remain in the moist cabinet or room and be read immediately upon opening the door. 5.2.1.2. For water storage tanks, position the reference temperature measuring device in a readable position in water as near as practical to the temperature
16、 recorder probe. Without removing the reference temperature measuring device from the water, record the temperature readings of both the temperature recorder and the reference temperature measuring device after the temperatures have stabilized. 5.2.1.3. Verify the accuracy of the temperature recorde
17、r by comparing the reading of the temperature recorder with that of the reference temperature measuring device during the normal operation of the moist cabinet, moist room, or water storage tanks. If the difference between the temperature readings is greater than 1C, the temperature recorder shall b
18、e adjusted to within 0.5C of the reference temperature measuring device. 6. REQUIREMENTS FOR MOIST CABINETS AND MOIST ROOMS 6.1. GeneralExcept during those times when specimens are being placed into or removed from storage, maintain the atmosphere in a moist cabinet or moist room at a temperature of
19、 23.0 2.0C and a relative humidity of not less than 95 percent. Maintain atmospheric conditions within a moist cabinet or moist room such that test specimens in storage are saturated with moisture to the degree needed to ensure that the exposed surfaces of all specimens in storage both look moist 20
20、16 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a M 201-3 AASHTO and feel moist (see Note 5). Equip all moist cabinets and moist rooms with a temperature recorder. The use of humidity recording devices
21、 is optional. Keep shelves on which fresh specimens are placed level. 6.1.1. The air temperature inside the moist cabinet or moist room shall be controlled with provisions made for heating or cooling, or both, as may be necessary. This shall be accomplished in one of two ways: 6.1.1.1. Thermostatica
22、lly control the air temperature within the moist cabinet or moist room when surrounding space is not conditioned. In this case, the sensing element for the controls shall be located inside the moist cabinet or moist room. 6.1.1.2. Thermostatically control the space surrounding the moist cabinet or m
23、oist room and manually control the temperature within the moist cabinet or moist room. 6.1.2. In either of the preceding cases, the laboratory shall demonstrate the ability of the controls to maintain the required temperature in the moist cabinet or moist room over an extended period of time. Data f
24、rom the temperature recorder that indicate that the temperatures are within the temperature limits specified in Section 6.1 shall be required as evidence of this ability. 6.2. Moist CabinetsA moist cabinet shall be constructed of durable materials, and the doors shall be tight fitting. The specified
25、 relative humidity shall be maintained by the use of one or more fog sprays, water sprays, or curtains of water on the inner walls that are directed such that the discharge will collect in a pool at or near the bottom of the moist storage section. 6.3. Moist Rooms: 6.3.1. GeneralThe walls of a moist
26、 room shall be constructed of durable materials, and all openings shall be provided with tight-fitting doors or windows (see Note 3). The specified relative humidity may be maintained in any convenient and suitable manner (see Note 4). Note 3Well-insulated walls will substantially help maintain nece
27、ssary conditions. Note 4A fog spray found suitable for this purpose is shown in Figure 1. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a M 201-4 AASHTO Figure 1Example of a Fog Spray for Maintaini
28、ng Relative Humidity in Moist Rooms (Full Scale)16.3.2. Moist Rooms Used in Cement TestingDurable shelving that is properly shielded to prevent droplets of water from falling on the surfaces of freshly molded specimens shall be available within each moist room. 6.3.3. Moist Rooms Used in Concrete Te
29、stingMaintain atmospheric conditions within each moist room such that test specimens in storage both look and feel moist (see Note 5). Do not expose specimens to dripping or running water. Note 5Maintenance of adequate water spray(s) and adequate spray distribution in the moist room will result in s
30、tored specimens looking and feeling moist and will maintain the required humidity. Inadequate numbers of spray nozzles, partially obstructed spray nozzles, or disturbances in the moist air system such as open doors, air-conditioning or heating drafts, or overly crowded shelf space may result in rela
31、tive dry spots. Specimen surface texture and age can influence the surface appearance and should be considered when specimens in localized areas do not look and feel moist. 7. REQUIREMENT FOR WATER STORAGE TANKS 7.1. GeneralTanks shall be constructed of noncorroding materials. Maintain storage water
32、 temperature at 23.0 2.0C, except for those times when specimens are being placed into or removed from storage, or tank maintenance is being performed. 7.2. Tank Temperature ControlsProvision for automatic control of water temperature at 23.0 2.0C shall be made when a tank is located in a room not h
33、aving temperature controlled within that range and in any other instance where difficulty in maintaining temperatures within the specified range is encountered. With the exception of water storage tanks located in a moist room Water LineApprox. 20 mL/minHollow Stainless Steel Sphere,40-mm Dia with W
34、elded FittingHorizontal Slots Described in Note.(Only two slots are shown, the thirdslot is on the back side of the sphere.)Air Line, Approx. 700 kPaNote: Cut three horizontal air slots around circumference of hollow sphereusing a 0.20-mm-thick diamond lapidary saw covering 120 to 150each and spaced
35、 approximately 5 mm apart. Air passing through theseslots strikes the water, which is flowing over the outer surface of thesphere, to produce a spray. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3
36、a M 201-5 AASHTO or moist cabinet, water storage tanks shall be equipped with a temperature recorder with its sensing element in the storage water. For the purpose of temperature recording, a group of water storage tanks may be considered one tank if the following three conditions are met: (1) the t
37、anks are interconnected with tubing that allows the water to flow between tanks, (2) some means of circulation is provided between tanks, and (3) temperature variation between tanks must not exceed 1.0C when checked and recorded weekly. 7.3. Tank Storage WaterThe water in a storage tank shall be sat
38、urated with calcium hydroxide to prevent leaching of calcium hydroxide from the specimens (see Note 6). Water not saturated with calcium hydroxide (high-calcium hydrated lime) may affect test results due to leaching of lime from the test specimens and shall not be used in storage tanks. To maintain
39、saturation with calcium hydroxide, excess calcium hydroxide shall be present. For the purposes of lime saturation to prevent leaching, lime means high-calcium hydrated lime, not calcium carbonate (limestone); see ASTM C51. The water in the storage tank shall be thoroughly stirred at intervals not to
40、 exceed 1 month to help replace calcium ions that have depleted. Tanks shall be cleaned and refilled with water containing 3 g/L of calcium hydroxide at intervals not to exceed 24 months (see Note 7). Note 6pH is not a reliable indicator of lime saturation in storage tank water because severe reduct
41、ions in dissolved calcium ions can occur before pH values are significantly reduced. Note 7The 3 g/L level is intended to provide a quantity of calcium hydroxide approximately two times that required for initial saturation. 7.3.1. Do not use continuously running fresh water or demineralized water in
42、 storage tanks because it may affect test results due to excessive leaching. A closed system, circulating the saturated limewater between or among storage tanks, may be used. 8. KEYWORDS 8.1. Cement paste; concrete; mixing rooms; moist cabinets; moist rooms; mortar; water storage tanks. 1One spray w
43、ill supply sufficient water to provide moisture to a space of 25 m3. Hollow spheres are available through McMaster Carr Supply Co., P.O. Box 4355, Chicago, IL 60680-4355. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
