Intrebari & Raspunsuri

WHAT IS CEMENT?

A finely ground grey powder
An inorganic compound of calcareous and argillaceous materials
Used in combination with sand, aggregates, water and admixtures to get a versatile and economical construction material called “concrete”
It is the main compound which binds all ingredients and gives strength to the concrete

WHAT ARE THE RAW MATERIALS USED TO MANUFACTURE CEMENT?

Calcareous (limestone obtained from mines) and argillaceous (clay or bauxite) materials and iron ore are the most commonly used raw materials in the manufacture of cement.

HOW IS CEMENT MANUFACTURED?

The process has four stages:

Extraction of limestone from the mines
The blending of ground limestone, clay or bauxite and iron ore or laterite in the right proportions which is then clinkered in rotary kilns at a high temperature to form “clinker”
Grinding of clinker with gypsum to form cement
Finally, storing it in silos, testing and dispatch

WHAT ARE THE MAJOR COMPOUNDS PRESENT IN CEMENT?

Tri-calcium Silicate(C₃S)
Di-calcium Silicate(C₂S)
Tri-calcium Aluminate(C₃A)
Tetra-calcium Alumino-Ferrite(C₄AF)

WHAT ARE THE FACTORS THAT AFFECT THE STRENGTH OF CONCRETE?

The factors that affect the strength of concrete are water-cement ratio, shape and size of aggregate, aggregate-cement ratio, degree of compaction, age of concrete, cement content and air entrainment and moisture in aggregate.

WHAT ARE THE REASONS FOR SLOW SETTING AND QUICK SETTING OF CEMENT MORTAR/CONCRETE?

Slow setting is due to:

Salts and chemicals in water, sand and aggregates
Application of less cement mortar/concrete
Cold weather conditions
High percentage of impurities seen usually in adulterated cement