The properties of concrete are broadly divided into how many categories?
Correct Answer: C. 2 (two)
📚 Detailed Explanation: Two Categories of Concrete Properties
Why C (2) is correct: All concrete properties are classified into exactly two major categories based on the state of the concrete: fresh concrete properties (relevant during production, transport, and placing) and hardened concrete properties (relevant during service life after setting and curing).
Two Categories of Concrete Properties
| Category | Definition | Key Properties |
|---|---|---|
| 1. Fresh Concrete Properties | Properties during the plastic state: from mixing to initial setting (~30–45 min for OPC) | Workability (slump, compacting factor, Vee-Bee time), Consistency, Mobility, Cohesion, Bleeding, Segregation tendency |
| 2. Hardened Concrete Properties | Properties after setting, hardening, and curing; relevant during service life | Compressive strength, Tensile/flexural strength, Modulus of elasticity, Creep, Drying shrinkage, Durability, Impermeability, Abrasion resistance |
Workability Tests (Fresh Concrete)
| Test | Standard | Measures |
|---|---|---|
| Slump test | IS 1199 Part 1 | Consistency; most common site test |
| Compacting factor test | IS 1199 Part 3 | Workability; more sensitive for stiff mixes |
| Vee-Bee test | IS 1199 Part 4 | Workability; best for very dry mixes |
| Flow table test | IS 9103 / EN 12350-5 | Flow; used for self-compacting concrete |
Strength Tests (Hardened Concrete)
| Test | Standard | Measures |
|---|---|---|
| Cube crushing test | IS 516 | Compressive strength (150 mm cube) |
| Cylinder test | ASTM C39 | Compressive strength (150×300 mm cylinder) |
| Split tensile test | IS 5816 | Indirect tensile strength |
| Non-destructive tests (NDT) | IS 13311 | In-place strength estimation; rebound hammer, UPV |
- Concrete properties are divided into exactly 2 categories: fresh and hardened.
- Fresh concrete properties govern placement quality; hardened concrete properties govern structural performance.
- The transition between the two states occurs at initial setting time (≈ 30–45 min for OPC per IS 4031 Part 5).