Proper proportioning of concrete, ensures:

Detailed Explanation: What Proper Proportioning Ensures

Why D (All options correct) is correct: The goal of concrete mix proportioning (mix design) is to select ingredient proportions that simultaneously achieve all performance requirements — strength, workability, durability, and impermeability (water tightness). All three listed properties are primary objectives of mix design.

Objectives of Concrete Mix Proportioning

Objective	How Proportioning Achieves It
Desired strength	By setting the appropriate w/c ratio (Abrams' Law)
Desired workability	By selecting water content, aggregate grading, and admixtures
Durability	By limiting max w/c ratio and ensuring minimum cement content per IS 456 Table 5
Water tightness	By achieving dense matrix with low permeability through low w/c and good compaction

• Proper proportioning satisfies all performance requirements simultaneously.
• IS 10262 process: target strength → w/c ratio → water content → cement content → aggregate proportions → trial mixes.