Question $1$

a$.$ For a highway with design speed of $115kph,$ what is the minimum radius of curvature for a horizontal curve? Assume side friction $\text{'}\text{'}$ as $0\mathrm{.}15$ and super elevation rate $\text{'}{e}^{\text{'}}$ as $0\mathrm{.}07.(4)$

b$.$ A $15-$degree horizontal curve, has posted speed of $75kph.$ Analyze this design and suggest changes if any. $(10)$

Question $2$

It is required to connect two straights $)=(50$ with a composite curve, comprising entry transition, circular arc and exit transition. The initial design parameters are $V=105k\frac{m}{h},q=0\mathrm{.}6\frac{m}{s^3},=0\mathrm{.}15$ and crossfall $1$ in $)=(0\mathrm{.}07.$

a$.$ Calculate the radius of the circular arc $(4$ marks$)$

b$.$ Determine the total length of the curve $(12$ marks$)$

c$.$ Calculate the actual value of superelevation $($in metres$)$ at the intersection of the transition and the circular curve given the width of road as $10m.(4$ marks$)$

Aide memoir

$S=\frac{L^2}{24}R,q=\frac{V^3}{{3\mathrm{.}6}^3}RL$

Question $3$

a$.$ What is a flexible pavement? $(3$ marks$)$

b$.$ What is the primary function of a pavement and how does the flexible pavement achieve this? $(1+2$ marks$)$

c$.$ Draw a sketch of the cross section of the flexible pavement indicating the layers. $(2)$

d$.$ State the functions of each of the layers of the flexible pavement $(5$ marks$)$

e$.$ Zambia mostly use flexible pavements as opposed to rigid pavements. Briefly explain the disadvantages of using this type of pavement. $(4$ marks$)$

f$.$ Mention any four properties that the top layer of a flexible pavement must possess. $(4$ marks$)$