Question

Reinforced Cement Concrete

For Concrete Mix 1, the typical mixture proportions for an average compressive strength to comply with f, of 3000 psi would have a w/cm of around 0.60. However, based on applicable exposure classes, the minimum specified strength, f.and maximum w/cm of the concrete should be:

a) 5500 esi. 0.52

b)4000 psi, 0.50

e) 4500 psi, 0.45

d) 5000 psi,0.40

Verified

### Question 36657

Reinforced Cement Concrete

Estimate the production of a single-engine two-axle wheel scraper whose travel time curves are shown in the figures in the previous slides based on the following information.
Haul road for a single pusher:
Section 2. Down a 4% grade, 2000 ft for hauling
Section 4. Up a 4% grade, 2000 ft for returning
Rolling resistance 100 lb/ton
Section 3. Level dumping area
Material: Sandy clay, 3200 lb/BCY, and 2650 lb/LCY
Maximum heaped volume = 30 LCY
Maximum payload = 95000 lb
Job efficiency = 50 min/hr
Operating conditions = average

### Question 36656

Reinforced Cement Concrete

1.A contractor is planning to use a crawler tractor with power shift transmission to push 1,500LCY. The tractor must haul the loose material down an 8% slope, where it will be stockpiled for later removal. The contractor has measured the tractor blade load measurement: the pile length12.6 ft, the pile width 8.1 ft, and the pile height 4 ft. The tractor weighs 24,400 pounds, and the coefficient of traction is estimated to be 0.7. The average haul distance is estimated to be 300 ft.The job efficiency is 50 minutes per hour. Performance characteristics of the tractor are shown in the previous figure. (note: 1 mi/hr = 88 ft/min)
1) What is the estimated productivity of the tractor?
2) Estimate the total hours to complete the work.
3) Determine if the tractor can perform the work in the given condition above.

### Question 36179

Reinforced Cement Concrete

1. Why the development length requirement has to be fulfilled for flexural reinforcement?
\text { Why the ACI code limit the } \mathrm{V}_{\mathrm{s}} \text { to } V_{s m a x}=\frac{V_{u}}{\phi}-V_{c}=8 \sqrt{f_{c}^{\prime}} b_{w} d ?

### Question 36177

Reinforced Cement Concrete

(50 pts) The simply supported beam shown in the figure below is being designed for shear. #3 stirrups (Grade 40) are to be used.
a. Draw the factored shear envelope for Vu (20 pts)
b. Determine the resistance to shear provided by the concrete. Are there any regions where no shear stirrups are required? (15 pts)
Design the stirrup spacing required to resist the maximum shear (15 pts)с.
Design the stirrup spacing required to resist the maximum shear

### Question 36176

Reinforced Cement Concrete

The concrete beam bulk shear capacity, Vc, will______ when subjected to axial tensile load
a, increașe
b. decrease
2. What are the three resisting mechanisms that make up the bulk shear strength, Vc?

### Question 36073

Reinforced Cement Concrete

Chloride ion limits for Concrete Mix 1 should be (% by weight of cement):

### Question 36072

Reinforced Cement Concrete

Maximum limits on supplementary cementitious materials are appropriate for ConcreteMix:

### Question 36071

Reinforced Cement Concrete

The applicable exposure dasses for Concrete Mix 9 are F2, S0, W1,CL.
a) True
b) Faise

### Question 36070

Reinforced Cement Concrete

The applicable exposure classes for Concrete Mix7 and 8 will be different since f, for structural requirements are different for each mix.
a) True
b) False

### Question 36069

Reinforced Cement Concrete

The applicable exposure classes for Concrete Mix 6 are:
a) FO, SO, WO, C2
b) F1, S1, W1.C1
F2, S0, WO, CO
d) FO, SO, Wo, co