(SEM V) THEORY EXAMINATION 2020-21 CONCRETE TECHNOLOGY

SECTION A (Any 2 Questions Explained Briefly)
 

What are supplementary cementitious materials?
Supplementary cementitious materials are materials added to concrete in addition to cement to improve its properties. Common examples include fly ash, silica fume, and ground granulated blast furnace slag. These materials improve workability, durability, and long-term strength of concrete and also help reduce the consumption of cement.
 

Give the statement of Abram’s law.
Abram’s law states that the strength of concrete is inversely proportional to the water–cement ratio, provided the concrete is properly compacted and cured. This means that as the water–cement ratio increases, the strength of concrete decreases.
 

SECTION B (Any 2 Questions Explained)
 

Write the factors to be considered for a mix design.
Concrete mix design depends on several factors such as required strength, workability, durability, type and size of aggregates, water–cement ratio, exposure conditions, and method of compaction. Proper consideration of these factors ensures economical concrete with desired performance and durability.
 

Describe the Vee-Bee consistometer test.
The Vee-Bee consistometer test is used to determine the workability of stiff concrete mixes. In this test, concrete is placed in a conical mould and subjected to vibration. The time taken by the concrete to change from cone shape to cylindrical shape is measured as Vee-Bee time. Higher time indicates lower workability.
 

SECTION C (Any 2 Questions Explained)
 

Explain manufacturing processes of cement.
Cement is manufactured mainly by wet and dry processes. In both processes, raw materials are crushed, proportioned, and heated in a rotary kiln to form clinker. The clinker is then cooled and ground with gypsum to produce cement. The dry process is more economical and widely used due to lower fuel consumption.
 

Discuss fly ash in concrete with its advantages.
Fly ash is a by-product of thermal power plants and is used as a partial replacement of cement in concrete. It improves workability, reduces heat of hydration, and enhances durability. Fly ash also makes concrete more economical and environmentally friendly by reducing cement usage.
 

Most Questions in This PDF Are Related To
 

Most questions in the Concrete Technology (KCE-051) paper are related to cement composition, properties of aggregates, workability tests, mix design, admixtures, durability of concrete, curing methods, special concretes such as fiber reinforced and self-compacting concrete, and sustainable materials like fly ash. Overall, the paper focuses on material properties and practical aspects of concrete construction.