Question

Factors promoting the alkali-aggregate reaction 1 point



a.Reactive type of aggregate



b.High alkali content in cement



c.Availability of moisture



d.Optimum temperature conditions



e. All the above

Answer 1

all of the above is the answe

Answer 2

Answer:

The correct option is (e) All the above.

Factors promoting the alkali-aggregate reaction are all the above.

Explanation:

Alkali aggregate reactions (AAR) is a reaction of aggregates in concrete with the alkali hydroxides in concrete, resulting in a hygroscopic gel. In the presence of moisture, this gel absorbs water which provokes expansion and cracking of the structure for multiple years.
The severely cracked structure is exposed to the weather conditions or is in contact with damp soil.

The Alkali-aggregate reaction has two forms:

• Alkali-silica reaction (ASR).
• Alkali-carbonate reaction (ACR).

The factors affecting the reactivity of aggregates are:

• Moisture availability
• Temperature
• Type of aggregates
• Particle size and its porosity
• Quantity of cement
• Permeability of paste.

Hence, the correct answer is (e) All the above.