AASHTO T152
Full Name
AASHTO T152 – Standard Method of Test for Air Content of Freshly Mixed Concrete by the Pressure Method
Scope
AASHTO T152 is a standard test method used to determine the air content of freshly mixed concrete. This test is essential for quality control in concrete production and construction, as the air content significantly influences the concrete’s workability, durability, and resistance to freeze-thaw cycles.
Key aspects of AASHTO T152:
- Principle: the pressure method is based on Boyle’s Law, which states that the pressure of a gas is inversely proportional to its volume at a constant temperature. The test involves placing a sample of freshly mixed concrete in a container of known volume and applying a known pressure. The change in volume of the concrete is measured, and from this, the air content can be calculated.
- Apparatus: the standard specifies the equipment required for the test, including a pressure meter, measuring bowl, strike-off bar, tamping rod, and calibration vessel. The pressure meter is a device that measures the pressure change and displays the air content directly.
- Procedure: the concrete sample is placed in the measuring bowl and consolidated to eliminate voids. The pressure meter is then attached, and a specified pressure is applied. The change in pressure is observed, and the air content is read from the meter’s gauge.
- Aggregate correction factor: the air content reading is then corrected for the amount of air entrapped in the aggregate. This correction factor is determined separately for each type of aggregate used.
Significance of AASHTO T152:
- Quality control: by measuring the air content of freshly mixed concrete, contractors and producers can ensure that it falls within the specified limits. This is crucial for producing durable concrete that can withstand freeze-thaw cycles and resist scaling.
- Mix design: the test results can be used to adjust the mix design by changing the amount of air-entraining admixture to achieve the desired air content.
- Workability: the air content influences the workability of concrete, and proper air entrainment improves the ease of placement and finishing.
AASHTO T152 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T152 standard.
Our laboratory offers comprehensive concrete testing services, including the determination of air content by the pressure method according to AASHTO T 152. Our experienced technicians utilize calibrated equipment and adhere to strict quality control procedures to ensure accurate and reliable results.
Contact us for more information.
Resources
Keywords
air content; pressure method; concrete; freshly mixed concrete; pressure meter; measuring bowl; tamping rod; aggregate correction factor; calibration vessel; air-entraining admixture; workability; durability