Materials — Quiz 3

Questions in this quiz (10)

1. A fatigue testing machine applies an average force of 18 kN to a specimen moving at a constant velocity of 0.06 m/s. Calculate the power required.

   • 720 W
   • 900 W
   • 1,080 W
   • 1,200 W

2. An asphalt binder has a flash point of 300°C. If the recommended mixing temperature is 170°C, calculate the safety margin between the flash point and mixing temperature.

   • 110°C
   • 120°C
   • 130°C
   • 140°C

3. In a shrinkage limit test, a soil sample has an initial moisture content of 30%, initial volume of 22.0 $$cm^3$$, final dry volume of 16.5 $$cm^3$$, and dry mass of 40 g. Calculate the shrinkage limit using $$SL=w-\left[\left(V_1-V_2\right)/W\right]\times\rho_w\times100$$

   • 14.5%
   • 16.25%
   • 21.0%
   • 25.4%

4. A steel component is subjected to cyclic loading with a maximum stress of 240 MPa and a minimum stress of -40 MPa (compression). Calculate the stress range.

   • 180 MPa
   • 200 MPa
   • 240 MPa
   • 280 MPa

5. In a pressure method air content test, the pressure meter reading is 6.1%. If the aggregate correction factor is 0.4%, calculate the air content of the concrete.

   • 5.3%
   • 5.7%
   • 6.1%
   • 6.5%

6. Calculate the cracking moment for a rectangular concrete beam with width 250 mm, depth 450 mm, and modulus of rupture fr = 3.8 MPa using $$Mcr = fr × Ig / yt$$.

   • 28.5 kN·m
   • 32.1 kN·m
   • 44.6 kN·m
   • 52.3 kN·m

7. A rebound hammer test on concrete gives a rebound number R = 42. Using the correlation $$fc = 0.8R − 5 (MPa)$$, estimate the compressive strength of the concrete.

   • 24.6 MPa
   • 28.6 MPa
   • 30.6 MPa
   • 33.6 MPa

8. Using the Paris law for fatigue crack growth $$da/dN = C(ΔK)^m$$, calculate the crack growth rate when $$C = 2.0 × 10^-11$$ $$(m/cycle)/(MPa√m)^m$$, $$m = 3.0$$, and the stress intensity range $$ΔK = 20 MPa√m$$.

   • $$1.60 × 10^{-4}$$ mm/cycle
   • $$3.20 × 10^{-4}$$ mm/cycle
   • $$1.60 × 10^{-5}$$ mm/cycle
   • $$6.40 × 10^{-4}$$ mm/cycle

9. A soil sample has particle sizes D60 = 3.6 mm and D10 = 0.30 mm. Calculate the coefficient of uniformity (Cu).

   • 8
   • 10
   • 12
   • 14

10. A soil sample has D60 = 3.6 mm, D30 = 1.0 mm, and D10 = 0.30 mm. Calculate the coefficient of curvature (Cc) using $$Cc = (D30)^2 / (D60 × D10)$$.

    • 0.77
    • 0.93
    • 1.04
    • 1.28