Slump Test Apparatus – identify the incorrect statement Regarding the standard slump cone used in the slump test for concrete, which statement below is incorrect?

Introduction / Context:The slump test assesses workability by measuring the subsidence of concrete after removing a standard mould. Accurate results depend on a correctly shaped and maintained mould and proper test procedure.

Given Data / Assumptions:

• Standard slump cone (Abrams cone).
• End faces are nominally parallel and the axis is normal to them.
• Clean internal surface ensures friction does not bias results.

Concept / Approach:The slump mould is a frustum of a right circular cone (not a hexagonal pyramid). The standard dimensions are typically 200 mm top diameter, 300 mm height, and 100 mm bottom diameter, with smooth internal surface.

Step-by-Step Solution:Identify the geometric shape required by the standard: frustum of a right circular cone.Compare each statement to the standard specification.Only the hexagonal pyramid statement conflicts with the requirement.

Verification / Alternative check:Inspection of certified slump cones confirms circular cross-sections; hexagonal forms are not used in the standard test.

Why Other Options Are Wrong:

• (a) and (b) describe correct geometry/tolerances.
• (c) is essential good practice for repeatable results.
• (e) cannot be correct because one incorrect statement exists.

Common Pitfalls:Using dented or out-of-round cones or dirty interiors can give misleading slump values; always verify apparatus condition.

Final Answer:The mould is in the form of a frustum of a hexagonal pyramid