If Quartzite, Granite, Basalt and Limestone are the aggregates to be used, the coefficient of thermal expansion for concrete will be highest with
- AQuartziteCorrect
- BGranite
- CBasalt
- DLimestone
Solution
Concept
Thermal expansion coefficient of concrete aggregates
Formula
NONE
Step-by-step solution
1. The coefficient of thermal expansion of concrete is strongly influenced by the dominant aggregate type used. 2. Quartzite has the highest silica content and highest thermal expansion coefficient compared to granite, basalt, and limestone. Answer: A
Explanation
The thermal expansion coefficient of concrete is strongly influenced by the mineral composition of its aggregate. Quartzite contains high concentrations of quartz, which possesses a higher thermal expansion coefficient compared to granite, basalt, and limestone. Therefore, concrete made with quartzite aggregate exhibits the highest thermal expansion, making option A correct.
Why the other options are wrong
B) Granite concrete has a lower coefficient of thermal expansion than quartzite concrete. C) Basalt concrete exhibits a lower thermal expansion coefficient than quartzite concrete. D) Limestone concrete has a lower coefficient of thermal expansion compared to quartzite concrete.
Shortcut
Thermal expansion order: Quartzite (highest) > Granite > Basalt > Limestone (lowest).
Common mistake
Selecting Granite or Basalt based on compressive strength rather than comparing the thermal expansion coefficients of the aggregates.
Correct answer: A) Quartzite