AASHTO T309
Full Name
AASHTO T309 – Standard Method of Test for Temperature of Freshly Mixed Portland Cement Concrete
Scope
AASHTO T309 is a standard test method used to determine the temperature of freshly mixed Portland cement concrete. This test is essential for quality control in concrete production and construction, as the temperature of fresh concrete significantly influences its setting time, strength development, and workability. Monitoring and controlling the concrete temperature is crucial for ensuring the desired properties and performance of the concrete in various applications.
Key aspects of AASHTO T309:
- Purpose: the primary objective of this test is to measure the temperature of fresh concrete accurately and consistently. This information is used to evaluate the concrete’s suitability for placement, adjust the mix design or placement procedures if necessary, and monitor the temperature during curing to ensure optimal strength development.
- Temperature Measuring Device: The standard specifies the use of a calibrated temperature measuring device, such as a thermometer or a thermocouple, that is capable of measuring the temperature within the expected range of fresh concrete with an accuracy of ±0.5°C (±1°F).
- Container: a non-absorptive container, large enough to hold a representative sample of concrete and provide adequate coverage for the temperature measuring device, is required. The container should be made of material that does not react with the fresh concrete.
- Procedure: the standard outlines the procedure for collecting a representative sample of fresh concrete, placing the temperature measuring device in the sample, and allowing sufficient time for the temperature to stabilize before recording the reading.
Significance of AASHTO T309:
- Quality Control: by monitoring the temperature of freshly mixed concrete, producers and contractors can ensure that it is within the acceptable limits specified in the project specifications. This is important for achieving the desired concrete properties and preventing potential problems such as thermal cracking or delayed setting.
- Mix design adjustments: if the concrete temperature is outside the desired range, the mix design can be adjusted by changing the temperature of the mixing water, aggregates, or other ingredients. Additionally, admixtures can be used to modify the setting time and workability of the concrete based on its temperature.
- Construction planning: the temperature of the concrete can influence the rate of construction. By knowing the concrete temperature, contractors can plan the placement and finishing operations accordingly, ensuring that the concrete is placed and finished before it sets.
AASHTO T309 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T309 standard.
Our laboratory offers comprehensive concrete testing services, including the determination of fresh concrete temperature according to AASHTO T 309. Our experienced technicians utilize calibrated temperature measuring devices and adhere to standardized procedures to provide accurate and reliable results for your construction projects.
Contact us for more information.
Resources
Keywords
temperature; concrete; freshly mixed concrete; portland cement concrete; thermometer; thermocouple; non-absorptive container; calibration