moulds and accessories for determination of density index (relative density) of cohesionless soils
1984 Edition

As per the standard, moulds and their accessories must be made from specific materials to ensure durability and functionality. The moulds can be constructed from copper alloy, brass, aluminium, or mild steel with a cadmium plating finish. Guide sleeves, surcharge base plates with handles, and surcharge weight bodies are manufactured from cadmium-plated mild steel, while the surcharge weights are filled with lead according to relevant IS codes. This combination of materials guarantees corrosion resistance and compliance with dimensional accuracy for soil density testing.

The standard specifies two primary mould volumes for testing: a smaller mould with a capacity of 3,000 cubic centimeters and a larger one with 15,000 cubic centimeters. Each mould features a smooth inner surface and is equipped with two handles, which may be either cast integrally or welded. The guide sleeve accompanies each mould and includes locking mechanisms. While exact dimensions are detailed in the standard’s figures, typically, the smaller mould might approximate 15 cm in diameter and 17 cm in height, whereas the larger mould could be near 25 cm in diameter and 30 cm tall. These dimensions ensure consistent sample preparation.

The surcharge weight comprises a mild steel body coated with cadmium to prevent corrosion, conforming to IS 513-1973. It is filled from the bottom with lead, adhering to IS 782-1978 specifications, to achieve the precise weight required for testing. This design ensures the surcharge weight applies an accurate and consistent load on soil samples during density index determination.

Dimensions of moulds and related accessories must comply with tolerances specified in the standard or, where not directly stated, conform to IS 2102 (Part 1) - 1980 medium class tolerances. Typically, critical dimensions have a tolerance of ±0.05 millimeters. The moulds must be smooth internally and have two integral or welded handles. These tolerances ensure the apparatus meets the required precision for reliable soil testing results.

This standard complements IS 2720 (Part 14) by providing detailed requirements for the moulds and accessories used to determine the density index of cohesionless soils via vibratory table methods. While IS 2720 (Part 14) defines the test procedure, IS 10837 ensures that the equipment used is standardized and consistent, resulting in accurate and repeatable measurement of relative density in soil testing laboratories.