Question

You are responsible for designing a concrete mixture to be used in the fabrication of a new

multi-story reinforced concrete parking garage on campus.

a)

Name four mixture ingredients (not water/not aggregates hint: cement type, admixtures, SCMs) you would consider for the optimal concrete mixture design to save the university some money without compromising durability and respecting structural specifications (strength) also, you need to make sure that the mixture is workable enough to be pumped in place.

b)

President Hargis would like to fast-track construction during the summer months to ensure delivery of the structure before the beginning of the football season. Would you change the mixture design ingredients proposed in a)? If no, provide a justification. If yes, what do you propose instead and why?

c)

Finally, the parking structure is scheduled to be built immediately after Bedlam game. During the Winter months. Would you change the mixture design ingredients proposed in b)? If no, provide a justification. If yes, what do you propose and why?

Answer 1

a) Portland pozzolana Cement can be used because of low cost but most preferably Rapid Hardening Cement is used because of high strength.

Water reducing admixtures to decrease the amount of water in the mixture to achieve high strength.

SCM - Fly ash and Silica Fume.

b) We would use Accelerating Admixture to increase the rate of hardening of concrete so it will be hardened earlier and be available to be used earlier than usual.

c) The admixtures used will be changed to accelerating admixtures to ensure fast construction and aie entraining agents to decrease the damage due to cold and frost to the structure.