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Questions from May 18, 2022

•  A normal-weight concrete has an average compressive strength of 20 MPa. What is the estimated flexure strength?  Three batches of concrete were prepared using the same materials and...
  May 19, 2022
• What is flowable fill? Discuss its ingredients and its advantages.  Two 150 mm * 300 mm concrete cylinders with randomly oriented steel fiber contents of 0 and 2% by weight, respectively. After...
  May 19, 2022
•  Discuss the concept of high-performance concrete. Discuss some of its properties that make it preferred over conventional concrete. Comparing PCC with mild steel, answer the following questions:...
  May 19, 2022
• Define solid and hollow masonry units according to ASTM C90. What are the advantages of masonry walls over framed (wood) walls? A concrete masonry unit is tested for compressive strength and produces...
  May 19, 2022
• A concrete masonry unit has actual gross dimensions of 190 mm * 190 mm * 190 mm. The unit is tested in a compression machine with the following results: Failure load = 436 kN Net volume of XXXXXXXXXXmm3...
  May 19, 2022
• A concrete masonry unit has actual gross dimensions of 190 mm * 190 mm * 190 mm. The unit is tested in a compression machine with the following results: Maximum failure load = 370 kN Net volume = 5125...
  May 19, 2022
• a Why is it important that the concrete masonry units meet certain absorption requirements? b. A portion of a normal-weight concrete masonry unit was tested for absorption and moisture content and...
  May 19, 2022
•  What are the objectives of the asphalt concrete mix-design process?  Why is it important to have optimum binder content in asphalt concrete? What would happen if a less-than-optimum binder...
  May 19, 2022
•  Using the AASHTO T 283 test, three HMA specimens were freeze–thaw conditioned and three were unconditioned. All the specimens had a diameter of 150 mm. Table P9.40 shows the thickness and...
  May 19, 2022
•  The moisture content of wood test was performed according to ASTM D4442 procedure and produced the following data: Mass of specimen in the green condition = 317.5 g Mass of oven-dry specimen =...
  May 19, 2022
•  A center-point bending test was performed on a 50 mm * 100 mm wood lumber according to ASTM D198 procedure with a span of 1.2 m and the 102 mm side is positioned vertically. If the maximum load...
  May 19, 2022
• A wood specimen having a square cross section of 50 mm * 50 mm (actual dimensions) was tested in bending by applying a load at the middle of the span, where the span between the simple supports was...
  May 19, 2022
•  What are the main advantages of engineered wood products over natural-timber members?  In addition to the LEED system, several other organizations have certification programs for wood....
  May 19, 2022
•  An epoxy is randomly reinforced with Kevlar fibers with 0.04 mm diameter, 15 mm length, 3.5 GPa ultimate tensile strength, and 50 MPa shear strength. Does this fiber length fully strengthen the...
  May 19, 2022
•  Getting measurements from Figure 11.20, determine approximate values of the following items for plain concrete, concrete with 2% steel fibers, and concrete with 3% steel fibers: a. Modulus of...
  May 19, 2022
• A fiber-reinforced polymer composite under isostrain condition consists of 35% fibers and 65% polymer by volume. The moduli of elasticity of the fibers and the polymer are 260 GPa and 3.4 GPa,...
  May 19, 2022
•  Repeat Problem 11.18 for 35% carbon fibers by volume. Repeat Problem 11.18 under isostress condition. An aligned and continuous fiber reinforced composite consists of fibers with an elastic...
  May 19, 2022
•  An FRP composite includes 40% continuous and aligned Aramid fibers by volume. The moduli of elasticity of the Aramid fibers and the epoxy resin matrix are 130 and 3.9 GPa, respectively. a....
  May 19, 2022
• A circular FRP composite rod with continuous and aligned fibers has a 75 mm diameter. The rod is simply supported with a span of 1.2 m and is subjected to three-point bending with a 1.2 kN center...
  May 19, 2022
• Show the max flexural stress distribution over the beam cross-section along thelength of the beam. The Width of the section is 200 mm, depth is 450 mm. The flangeand web dimensions of the...
  May 19, 2022
• Give a geometric argument based on similar triangles to show that the chordal distance between a point z and 8 (that is, the distance between the projection Z and the north pole) is given by [HINT:...
  May 19, 2022
• Use the result of Example 4 and properties of stereographic projection to show that the inversion w = 1/z maps any circle in the z-plane to either a circle or a line in the w-plane, and the same holds...
  May 19, 2022
• Sketch the isotherms for the edge-temperature distribution in Fig XXXXXXXXXXDoes this configuration violate the maximum principle? Sketch the isotherms for the edge-temperature distribution in Fig. 2.19....
  May 19, 2022
• Using only real arithmetic operations, write a computer program that, when given as input the real and imaginary parts (x, y) of z = x + iy, produces as output the real and imaginary parts of (a) e z...
  May 19, 2022
• Using only real arithmetic operations, write a computer program whose input (x, y) is the real and imaginary parts of z = x + iy and whose output is the real and imaginary parts of (a) Log z (b)...
  May 19, 2022