Civil Engineering Materials #$6\mathrm{.}34$

Referring to Table. $,$ Mix No$.1$ was designed to produce a $25mm(2$ in$.)$ slump without water reducer. Mixes Nos. $2-4$ are trial mixes with water reducer. All mixes have the same amounts of aggregate and cement, different amounts of mixing water.

If the compressive strength at $28$ days follows the results shown in Figure $6\mathrm{.}8,$ determine the following items:

a$)$ Water$-$cement ratio of each mix.

b$)f_c^{\text{'}}$ of each mix.

c$)$ The weight of mixing water required for a mix with water reducer having a $50mm(2$ in$.)$ slump using the same amounts of aggregate and cement shown in the table.

d$)$ f$\text{'}$c of the mix in Item c$.$

e$)$ Comment on the effect of adding water reducer to the mix and discuss how to make use of it to increase the compressive strength of concrete.

$*$Assume all aggregates are in the SSD moisture state.