1、Standard Method of Test for Temperature of Freshly Mixed Portland Cement Concrete AASHTO Designation: T 309-15 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS 3b T309-1 AASHTO Standard Method of Test for Temperatur
2、e of Freshly Mixed Portland Cement Concrete AASHTO Designation: T 309-15 1. SCOPE 1.1. This test method covers the determination of temperature of freshly mixed portland cement concrete. 1.2. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to
3、address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices. WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure. 2.
4、 REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 18, Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories R 60, Sampling Freshly Mixed Concrete 2.2. ASTM Standards: C1064/C1064M, Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement
5、 Concrete E77, Standard Test Method for Inspection and Verification of Thermometers 3. SIGNIFICANCE AND USE 3.1. Concrete temperature is one of the most important factors influencing the quality, time of set, and strength of concrete. Controlling concrete temperature and limiting placement to certai
6、n air temperatures will reduce or eliminate many problems, including those associated with strength development and durability. 3.2. The temperatures of concrete and air may be used to determine compliance with project requirements, the type of curing and protection that is needed, as well as the le
7、ngth of time curing and protection should be maintained. 4. APPARATUS 4.1. ContainerThe container shall be made of nonabsorptive material and large enough to provide at least 75 mm (3 in.) of concrete in all directions around the sensor of the temperature measuring device; concrete cover must also b
8、e at least three times the nominal maximum size of the coarse aggregate. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS 3b T309-2 AASHTO 4.2. ThermometerA calibrated thermometer capable of measuring
9、the temperature of the freshly mixed concrete to 0.5C (1F) throughout the temperature range likely to be encountered. 4.3. Reference ThermometerThe reference temperature measuring device shall be readable to 0.2C (0.5F) that has been verified and calibrated. The calibration certificate or report ind
10、icating conformance to the requirements of ASTM E77 shall be available for inspection. 5. HAZARDS 5.1. Fresh mixed cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure. 6. STANDARDIZATION 6.1. Standardize each thermometer in accordance with R 18 a
11、nd whenever there is a question of accuracy. Perform standardization by comparing readings on the thermometer with another calibrated thermometer at two temperatures at least 15C (27F) apart. 7. SAMPLING 7.1. When the only purpose is measuring the temperature of freshly mixed concrete, it may be det
12、ermined in the transporting equipment, forms, or sample containers. 7.2. When other testing is also being performed, sample in accordance with R 60. 8. PROCEDURE 8.1. Place sensor of the thermometer in the freshly mixed concrete so that it has at least 75 mm (3 in.) of concrete cover in all directio
13、ns around the sensor. 8.2. Gently press the concrete in around the sensor of the thermometer at the surface of the concrete so that air cannot reach the sensor. 8.3. Leave the sensor of the thermometer in the freshly mixed concrete for a minimum of 2 minutes or until the temperature reading stabiliz
14、es. 8.4. Complete the temperature measurement of the freshly mixed concrete within 5 minutes of obtaining the sample. 8.4.1. Concrete containing aggregate of a nominal maximum size greater than 75 mm (3 in.) may require up to 20 minutes for the transfer of heat from the aggregate to the mortar after
15、 batching. 8.5. Read and record the temperature to the nearest 0.5C (1F). 9. REPORT 9.1. The report shall include the following: 9.1.1. Measured temperature of the freshly mixed concrete to the nearest 0.5C (1F). 10. PRECISION AND BIAS 10.1. No precision or bias statements are available at this time
16、. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS 3b T309-3 AASHTO 11. KEYWORDS 11.1. Concrete temperature; hydraulic cement; portland cement. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
