Glossary of Terms Relating to Cement Concrete, Part 10: Tests and Testing Apparatus
1973 Edition

The standard defines consistency as the relative ease with which freshly mixed concrete or mortar flows. Concrete consistency is typically measured using the slump test, while flow tests are used for mortar, cement paste, or grout. Normal consistency refers to the moisture content at which the mix achieves acceptable workability, determined for neat cement pastes by the Vicat apparatus as specified in IS 4031-1968. This terminology ensures that concrete mixes meet practical requirements for placement and finishing.

IS 6461 Part 10 outlines terminology for various testing equipment essential in concrete evaluation. Included apparatus are compression testing machines for measuring compressive strength, slump cones for assessing workability, Vee-Bee apparatus for consistency, compaction factor devices, flow tables to evaluate mix flow, sieves for aggregate grading, and penetrometers for cement setting time. This standard promotes uniform identification and understanding of these instruments to maintain consistency in concrete testing.

This part of the standard provides clear definitions for terms associated with strength testing, including the description of test specimens such as cubes and cylinders, the curing process that involves controlled moisture and temperature conditions, and the operation of testing machines applying loads to specimens. Key terms include compressive strength — the maximum load per unit area concrete can endure — and curing protocols essential for reliable strength development. These definitions support uniform reporting and interpretation of strength test results.

IS 6461 Part 10 specifies terms concerning the preparation and conditioning of concrete samples for testing. Standard curing is defined as maintaining specimens under controlled temperature (typically 27 ± 2°C) and relative humidity (≥95%) for specified durations (commonly 7, 14, or 28 days) to ensure consistent hydration and strength gain. The glossary also references established Indian and international standards harmonizing terms such as curing, molding, demolding, and sample conditioning to promote reproducibility in test outcomes.

The glossary describes viscosity as the resistance to flow quantified by the ratio of shear stress to shear rate, commonly measured using torque viscometers. These devices determine the torque needed to rotate an element within a slurry, correlating to the mixture's viscosity. Fluidity, inversely related to viscosity, reflects how easily the cementitious mix flows. Normal consistency and consistency factor terms further characterize the pumpability and workability of grout and concrete, with specific tests such as slump or flow tests used to assess these properties.