$($a$)$ Portland Cement Concrete, Type $1$ with specific gravity $3\mathrm{.}15$ will be used for the construction of $10$ No$.$ Circular Tank Bases to receive $10$No$.$ Fusion Bonded Powder Coated Bolted $20$ML Steel Tanks, as part of the National Water Commissions "Drought Mitigation Plan" to provide augmented water storage for the Kingston Metropolitan Area.

The angular coarse aggregate is well graded and has the following properties: Largest nominal aggregate particle size is $19$ mm ; Bulk Specific Gravity is $2\mathrm{.}70$ ; Moisture Content is $1\mathrm{.}5\%$; Water absorption is $0\mathrm{.}6\%.$ The fine aggregate, which is well graded medium sand, has a bulk specific gravity of $2\mathrm{.}50$ with a moisture content of $4\mathrm{.}0\%$ and water absorption of $3\%.$

If the aggregate cement ratio is $6\mathrm{.}5,$ the water cement ratio is $0\mathrm{.}50$ and the proportion of coarse to fine aggregate is $80$:$20,$ design a trial mix comprising $2,000kg$ of combined aggregates to meet a compressive cube test of $30$ MPa at $28$ days, where $1$ MPa is equivalent to $145\mathrm{.}0377$ psi.

$($Take $1$ bag of cement $=42\mathrm{.}7kg$ and density of water $=1000k\frac{g}{m^3}$

$(12$ marks$)$