Concrete aggregates — classification by weight, shape, and surface texture Select the comprehensive statement that correctly lists common classification schemes for concrete aggregates used in mix design and construction.

Introduction / Context:
Aggregates occupy the bulk volume of concrete and strongly influence workability, strength, shrinkage, and durability. Engineers classify aggregates in several ways to anticipate performance and select suitable materials for a given application.

Given Data / Assumptions:

• Multiple classification criteria are valid simultaneously.
• Terminology may vary slightly across references, but the categories are widely recognized.
• Focus is on practical construction-oriented classification.

Concept / Approach:
Common aggregate classifications include: (1) by relative density/bulk density (lightweight, normal weight, heavyweight) linked to mineralogy and source; (2) by particle shape (rounded, irregular/subrounded, angular, flaky/elongated) affecting workability and packing; and (3) by surface texture (glassy, smooth, granular, rough, crystalline, honeycombed, porous), which influences paste bond and water demand. These classifications help predict concrete behaviour and guide adjustments in mix proportions or admixture use.

Step-by-Step Solution:

Verification / Alternative check:
Design guides and codes adopt these same schemes in aggregate acceptance criteria and in recommendations on grading and fines content.

Why Other Options Are Wrong:

• Picking any single scheme omits other widely used and necessary classifications for mix design and performance prediction.

Common Pitfalls:
Using only nominal size to characterize aggregates; ignoring shape and texture impacts on water demand and cement content.

Final Answer:
All the above