Question #1 (10 pts.):
A 4.5” slab of plain (non-reinforced) concrete for a sidewalk and pavilion outside of a building in central Long Island is to be made with the following specifications:
• Design compressive strength: 3200 psi, based on 15 tests of samples having a standard deviation of 350 psi
• Air entrained
• Fine aggregate: G = 2.52, FM = 2.5
• Coarse aggregate: G = 2.67, bulk density = 2750 lb/cy
Determine the following:
i. w/c ratio, largest nominal max. coarse aggregate size, % coarse aggregate, % air (2 pts.)
ii. weight of water, weight of cement, and weight of coarse aggregate to be used per cubic yard of concrete (1 pt.)
iii. weights and volumes of water, cement, air, coarse aggregate, and fine aggregate needed to mix a 25-yard batch of this mix (3 pts.)
Also:
• Specify two admixtures that might be used for this mix based on the provided information, and why to use it. (2 pts.)
• For the columns supporting a canopy in the pavilion, a composite of this concrete poured into a PVC (polyvinyl chloride) sleeve is being considered. Why we might use this for these columns? (Give specific reasons based on the characteristics of the individual materials.) (2 pts.)
Question #2 (3 pts.):
Standard bricks (3 ½” x 8”) are to be used to accent the sidewalk and pavilion in Question #1.
Severe weathering bricks are specified, and a sample of those provided by the brick vendor yields the following test results:
• Failure load: 85 kips
• Dry weight: 5.76 lbs.
• Weight after 24-hour submersion: 6.48 lbs.
• Weight after 5-hour boiling: 6.75 lbs. Based on the provided information:
• determine whether the brick meets the requirements for compressive strength, absorption, and saturation (2 pts.)
• Also, discuss whether it would be preferable to use clay brick or CMU in this application, and why. (1 pt.)
Question #3 (5 pts.):
The asphalt whose characteristics are shown in the table below will be used to pave a parking lot in front of the building indicated in Question #1. For this asphalt:
i. Complete the table, and calculate the VMA, VTM, VFA, and theoretical max. G. (2 pts.)
ii. If the stability of this asphalt was tested to be 2300 pounds, and the flow was found to be 0.08 inches, compare all of the values of this mix to those in the Marshall mix curves found on Slide 36 of Presentation #5. (2 pts.)
iii. Discuss the suitability of this mix in provided scenario based on its characteristics (1 pt.)
