Using a CEM I cement type, prepare a British $($DOE$)$ mix design for a reinforced concrete wall

which will undergo $100-$year exposure to carbonation under moderate humidity conditions.

The specified characteristic compressive strength is $41$ MPa, with a standard deviation of $3\mathrm{.}52$

MPa. In addition, the maximum permissible defective level below the characteristic strength is

$0\mathrm{.}5\%.$ The available coarse aggregate is uncrushed. The capacity of the trial mix should be

$0\mathrm{.}08$ m$3$