Unit 10 Module: Determination of the Time Setting of Portland Cement Flashcards
Objectives: 1. Describe the importance of classifying Portland cement. 2. Identify the properties of Portland cement. 3. Explain the importance of testing the setting time of Portland cement.
is the most common type of cement in general use around the world, used as a
basic ingredient of concrete, mortar, stucco, and most non-specialty grout.
Portland cement
What are the most common products that includes portland cement as its basic ingredient
concrete, mortar, stucco, and most non-specialty grout.
It was developed from other
types of hydraulic lime in England in the mid-19th century and usually originates from limestone
Portland cement
In what material does portland cement originate
Limestone
What chemical is this?|
(C3S)
Tricalcium silicate
What chemical is this?
(C2S)
Dicalcium silicate
What chemical is this?
(C3A)
Tricalcium aluminate
What chemical is this?
(C2AF)
Tetracalcium aluminoferrite
When Portland cement is mixed with water its chemical compound constituents undergo a series
of chemical reactions that cause it to harden. This chemical reaction with water is called ____
Hydration
starts as soon as the cement and water are mixed.
Hydration
Hydrates and hardens rapidly and is largely responsible for initial set and early
strength. Portland cements with higher percentages of (35 will exhibit higher early strength.
Tricalcium Silicate (C3S)
Hydrates and hardens the quickest. Liberates a large amount of heat almost
immediately and contributes somewhat to early strength. Gypsum is added to Portland cement to retard
C~ hydration. Without gypsum, C?A hydration would cause Portland cement to set almost immediately
after adding water.
Tricalcium Aluminate(C3A)
Hydrates and hardens slowly and is largely responsible for strength increases
beyond one week.
Dlcalcium Silicate(C2S)
admirably suited to all construction
work which is free from sulphate attack, has a medium rate of strength development and heat generation
and has an adequate resistance to dry shrinkage and cracking, but has less resistance to chemical attack.
Ordinary Portland Cement (Type I)
Used as a precaution against moderate sulfate attack and usually generate less heat at a slower
rate than Type I cement.
Moderate Sulfate Resistance(Type II)