Q1) Design a concrete mix by using ACIMethod of Mix Design having 28-day characteristic meanstrength of 27 MPa for a deck of a residentialbuilding at Nebraska. Dry weather and gradually warmingtemperatures may be expected throughout the working week. Freshconcrete composed of a slump of 90 mm and maximum aggregate size of25 mm. Determine the amount of water reducing admixture to be usedfor 0.24 % and 0.65 %. Deck is aflat surface capable of supporting weight, similar to a floor, buttypically constructed outdoors, often elevated from the ground, andusually connected to a building. Decks that need piers or footingsmust have them installed below the frost line. This will keep thepiers from heaving up out of the ground from the strength of thefreeze. Reinforcing steel will help keep the piers from cracking.The freeze or frost line is the depth to which the soil freezes orhas been known to freeze at some point in the past. It isabsolutely critical that the foundations of buildings extend belowthis point in a soil profile. Except for a few arid locations,soils typically contain water and this water expands approximatelynine percent in volume when it freezes. The frost line depth is notconsistent around the nation because there
is such a dramatic difference in climate from state to state. Deck is composed of 2.5 cm reinforcement and there is no need for piers. The material properties are as follows:
For Coarse aggregate: SSD bulk specific gravity: 2.75,absorption capacity = 1.5 %, total moisture: 2.5 %, Dry-rodded unitweight: 1514 kg/m3.
For Fine aggregate: SSD bulk specific gravity: 2.65, absorptioncapacity = 1.0 %, surface moisture: 3 %, F.M: 2.6.
Cement: Type V, Sp.Gravity: 3.23
Probability constant: 1.22 and standard deviation: 2 MPa
