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IS 9799:1981 is the Indian Standard (BIS) for pressure meter for determination of air content of freshly mixed concrete. This standard lays down the specifications for the design, construction, and calibration of pressure-type meters used for determining the air content of freshly mixed concrete. It covers two main types of meters (Type A and Type B), detailing their constituent parts like the measuring bowl, cover assembly, and pressure gauge to ensure accuracy and consistency in testing.
Specification for pressure meter for determination of air content of freshly mixed concrete
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Cement, Concrete, Aggregates and RCC
Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
Specifies the procedure for determining air content in fresh concrete using a Type B pressure meter.
EN 12350-7:2019European Committee for Standardization (CEN), Europe
HighCurrent
Testing fresh concrete - Part 7: Air content - Pressure methods
Covers the determination of air content of compacted fresh concrete using a water column or pressure gauge meter.
AASHTO T 152-17American Association of State Highway and Transportation Officials, USA
HighCurrent
Standard Method of Test for Air Content of Freshly Mixed Concrete by the Pressure Method
Provides a test method for air content by pressure, technically equivalent to ASTM C231.
AS 1012.4.2:2014Standards Australia, Australia
HighCurrent
Methods of testing concrete, Method 4.2: Determination of air content of freshly mixed concrete - Pressure method
Details the pressure method for measuring the air content of freshly mixed, compacted concrete.
Key Differences
≠The IS 9799 standard, published in 1981, has not been updated, whereas international equivalents like ASTM C231 and EN 12350-7 have been revised multiple times (e.g., 2017 and 2019 respectively), incorporating modern practices and refined procedures.
≠IS 9799 specifies a minimum container capacity of 0.005 m³ (5 litres). ASTM C231 requires a larger minimum size of 0.20 ft³ (approx. 5.7 litres) for concrete with aggregates up to 2 inches.
≠While all standards require an aggregate correction factor, ASTM C231 provides a more detailed and rigorous procedure for its determination compared to the general description in IS 9799.
≠IS 9799's compaction instruction is 'tamped thoroughly', which is less specific than ASTM C231 and EN 12350-7, both of which mandate a specific number of layers and strokes (e.g., 2 layers, 25 strokes per layer for a standard bowl).
Key Similarities
≈All standards are based on the same physical principle: Boyle's Law, relating pressure and volume changes to determine the amount of compressible air in the concrete mix.
≈The fundamental design of the apparatus (Type B meter) is consistent across all standards, comprising a measuring bowl and a sealed cover assembly with a pressure chamber, gauge, and operating valves.
≈All standards acknowledge the need for an 'aggregate correction factor' to account for the air trapped within aggregate particles, which must be subtracted from the initial meter reading.
≈The scope is universally focused on determining the air content of freshly mixed concrete, and all standards note the method's unsuitability for concrete made with lightweight or highly porous aggregates.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Container Capacity
0.005 m³ (5 litres)
0.20 ft³ (≈ 5.7 litres)
ASTM C231
Tamping Rod Diameter
16 mm
5/8 in (15.9 mm)
ASTM C231
Compaction (for standard bowl)
In 2 layers, 'tamped thoroughly'
In 2 layers, 25 strokes per layer
ASTM C231
Pressure Gauge Readability
0.1% air content divisions
Graduated to 0.1% air content or finer
ASTM C231
Nominal Operating Pressure
Approx. 0.1 N/mm² (≈ 14.5 psi)
Determined by calibration, typically 15 psi (103 kPa)
ASTM C231
Maximum Aggregate Size
Not explicitly stated (typically ≤ 40 mm in practice)
2 in (50 mm)
ASTM C231
Vibration Frequency (if used)
≥ 12000 vib/min (from IS 1199)
≥ 9000 vib/min [150 Hz]
ASTM C231
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Nominal capacity of measuring bowl (Type A)0.005 m³
Nominal capacity of measuring bowl (Type B)0.007 m³
What is the main difference between Type A and Type B pressure meters?+
Type A meter requires inverting the sealed unit to allow water into the chamber, while Type B uses a piston to force water into the chamber from a cylinder.
Which IS code describes the test method using the pressure meter specified here?+
IS 1199 (Part 4) 'Methods of Sampling and Analysis of Concrete, Part 4: Determination of Air Content of Fresh Concrete'.
What is the specified capacity for the measuring bowl?+
The nominal capacity is 0.005 m³ for a Type A meter and 0.007 m³ for a Type B meter (Clause 3.1.2).