(SEM V) THEORY EXAMINATION 2024-25 CONCRETE TECHNOLOGY

Subject Code: BCE051
Maximum Marks: 70
Time: 3 Hours
Paper ID: 310887

Paper Overview

SECTION A (2 × 7 = 14 Marks)

(Short answer questions — definitions and basic concepts)

a. Explain the field tests for cement.
b. Explain hydration of cement and list the types of compounds formed during hydration.
c. Explain superplasticizers.
d. Explain curing and list different methods adopted for curing.
e. Define concrete mix design.
f. Distinguish high performance concrete and high strength concrete.
g. Explain geo-polymer concrete.

SECTION B (Attempt any three × 7 = 21 Marks)

(Descriptive questions – medium-length explanations)

a. Discuss the classification of aggregates.
b. Discuss the role of air-entraining admixtures in concrete.
c. Describe the slump test for measuring the workability of concrete.
d. Explain the purpose and requirement of concrete mix design.
e. Explain fibre-reinforced concrete, its properties, and uses.

SECTION C (Attempt one part from each question × 7 = 35 Marks)

(Long answer/application-oriented questions)

Q3.
(a) Explain briefly the ingredients of concrete and their functions.
OR
(b) Explain the properties and uses of rapid hardening cement.

Q4.
(a) Describe mineral admixtures and discuss their function in concrete.
OR
(b) Discuss the functions of (i) Accelerators and (ii) Retarders.

Q5.
(a) Explain the importance of curing and list different methods of curing.
OR
(b) Explain the factors affecting the durability of concrete.

Q6.
(a) Explain the purpose and requirement of concrete mix design.
OR
(b) Discuss the steps of concrete mix design as per IS 10262:2019.

Q7.
(a) Explain Ferrocement — its properties and uses.
OR
(b) Explain the properties and uses of self-compacting concrete.

Key Topics for Revision

Cement Properties & Testing

Field tests (colour, temperature, float test, soundness).

Laboratory tests (setting time, fineness, compressive strength).

Hydration of Cement

Compounds: C₃S, C₂S, C₃A, C₄AF.

Products: C-S-H gel, Ca(OH)₂.

Stages: initial reaction, dormant period, acceleration, hardening.

Admixtures

Superplasticizers: Improve workability without extra water.

Air-Entraining Agents: Increase freeze-thaw resistance.

Accelerators & Retarders: Control setting time.

Mineral Admixtures: Fly ash, silica fume, GGBS — improve durability.

Curing of Concrete

Methods: water curing, steam curing, membrane curing, curing compounds.

Importance: ensures hydration, strength gain, reduces shrinkage cracks.

Concrete Mix Design

IS 10262:2019 procedure — determine water content, w/c ratio, coarse/fine aggregate ratio, trial mix.

Purpose: achieve desired strength, durability, economy.

Special Concretes

High Strength Concrete (HSC): fck > 60 MPa.

High Performance Concrete (HPC): High workability, durability, low permeability.

Fibre Reinforced Concrete (FRC): Fibres (steel, glass, polypropylene) improve tensile strength.

Geo-Polymer Concrete (GPC): Uses fly ash + alkaline activator; eco-friendly.

Ferrocement: Thin section reinforced with wire mesh – used in shells, boats.

Self-Compacting Concrete (SCC): Flows without vibration; highly workable.

Durability Factors

Water-cement ratio, permeability, curing, environmental exposure, chemical attack.

Workability Tests

Slump test, compaction factor test, Vee-Bee test.