Question

Problem 3: {10}

Which particular type of cement (among the five ASTM types) would be the MOST suitable for each of the following structural applications? Provide brief justifications for your answer.
Note that if there is nothing special about the structure or its environmental exposure, then using Type I is the cheapest option.

1. (i) New construction of a highway bridge column with sufficient time to set

2. (ii) Basement concrete wall of a building (soil may contain excessive sulfates)

3. (iii) Thick concrete wall for a building in Arizona desert

4. (iv) Highway patch repair

5. (v) Interior concrete slab of a 4-storey building

Answer 1

(i) Type II cement would be most suitable as bridge column would have a large structure and could develop large heat of hydration causing cracks in the concrete. Also their could be chance of sulphate attack to the structure due to sulphates present in water. (ii) Type V cement should be used because concrete is exposed to the risk of deterioration due to sulphate attack as soil may contain excessive sulphates. (iii) Type IV cement should be used as the wall is thick and could produce large heat of hydration causing cracks in the concrete. Therefore cement with low heat of hydration is preferred. (iv) Type III cement would be most suitable because the concrete should develop strength rapidly as the load would be applied in short period of time. (v) Type I cement would be most suitable as the concrete is to be placed under ordinary conditions with no special properties to be required.