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IS 9459:1980 is the Indian Standard (BIS) for apparatus for use in measurement of length change of hardened cement paste, mortar and concrete. This standard specifies the requirements for the apparatus used to measure the change in length of hardened specimens of cement paste, mortar, and concrete. It covers the detailed specifications for the length comparator, moulds for preparing specimens, gauge studs, and the reference bar used for calibration.
Specification for apparatus for use in measurement of length change of hardened cement paste, mortar and concrete
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Cement, Concrete, Aggregates and RCC
Standard Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete
Directly specifies requirements for molds and length comparators for measuring length change.
BS EN 12390-16:2019BSI (British Standards Institution), UK / CEN, Europe
HighCurrent
Testing hardened concrete - Part 16: Determination of shrinkage of concrete
Specifies a full test method, including detailed apparatus requirements similar to IS 9459.
ISO 1920-8:2020ISO (International Organization for Standardization), International
MediumCurrent
Testing of concrete — Part 8: Determination of drying shrinkage of concrete for shrinkage-compensating concrete
Details the apparatus and method for measuring drying shrinkage, with a focus on a specific concrete type.
Key Differences
≠IS 9459 qualitatively describes the comparator frame as 'rigid', whereas ASTM C490 provides a quantitative performance requirement: the frame must not deflect more than 0.002 mm under a 9.8 N load applied to the indicator stem.
≠The interface between the comparator and the specimen's gauge stud differs. IS 9459 specifies a comparator with a spherical contact point measuring on a stud with a flat or recessed end, while ASTM C490 specifies a comparator with a conical point that fits into a corresponding conical recess in the gauge stud.
≠IS 9459 specifies mortar mould cross-sections of 25x25 mm or 40x40 mm. While ASTM C490 also uses 25x25 mm [1x1 in], it does not include the 40x40 mm option common in European practice for prisms.
Key Similarities
≈Both IS 9459 and its international counterparts primarily aim to standardize the apparatus (molds and length comparator) for accurate and repeatable measurement of dimensional changes in cementitious materials.
≈All standards mandate the use of a reference bar made from a material with a very low coefficient of thermal expansion (e.g., Invar steel) to periodically calibrate the length comparator.
≈The standards require that gauge studs embedded in the specimen be made from a corrosion-resistant material like stainless steel to ensure the integrity of the measurement points over time.
≈The fundamental components are identical across the standards, consisting of rigid molds for casting specimens and a length comparator with a fixed anvil and a movable spindle attached to a high-precision dial gauge.
Parameter Comparison
Parameter
IS Value
International
Source
Dial Gauge Least Count / Resolution
0.002 mm
≤ 0.002 mm
ASTM C490/C490M-17
Reference Bar Max Thermal Expansion
≤ 1.0 x 10⁻⁶ per °C
≤ 0.9 x 10⁻⁶ per °C (≤ 0.5 x 10⁻⁶ per °F)
ASTM C490/C490M-17
Comparator Frame Rigidity Check
Not specified quantitatively (described as 'rigid')
Deflection < 0.002 mm under a 9.8 N load
ASTM C490/C490M-17
Nominal Specimen Gauge Length
250 mm
250 mm [10 in]
ASTM C157 (uses C490 apparatus)
Typical Mortar Specimen Cross-Section
25 x 25 mm or 40 x 40 mm
25 x 25 mm [1 x 1 in]
ASTM C490/C490M-17
Gauge Stud Material
Stainless steel
Stainless steel or other corrosion-resistant metal
ASTM C490/C490M-17
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Dial gauge least count0.002 mm
Standard gauge length250 mm
Gauge stud diameter6.5 ± 0.1 mm
Reference bar thermal expansion coefficient (max)2 x 10⁻⁶ per °C