HOMEWORK ASSIGNMENT #$1-$ INDIVIDUAL

Design the following concrete mixes using the absolute volume method as outlined in the

handout and described in class.

Mix Design Problem #$1$:

Conditions and Specifications:

Concrete is required for an exterior reinforced concrete wall $($freeze thaw cycles$).$ A specified

compressive strength, $f^{\text{'}},$ of $4,500$ is required at $28$ days using Type I cement. The design

calls for a minimum $1\mathrm{.}5$ in $.$ of concrete cover over the reinforcing steel. The minimum distance

between reinforcing bars is $2$ in $.$ The only admixture allowed is for air entrainment. Assume an

air content of $7\%.$ No statistical data on previous mixes are available.

The materials are as follows:

Cement:

Type I, ASTM C $150,$ with a relative density of $3\mathrm{.}15.$

Coarse Aggregate:

Select the maximum size gravel $($it being well$-$graded will be assumed$)$ with an oven$-$dry relative

density $($specific gravity$)$ of $2\mathrm{.}65,$ absorption of $0\mathrm{.}5\%($moisture content at SSD condition$)$ and

oven$-$dry rodded bulk density $($unit weight$)$ of $95$ lb per cu ft$.$ The laboratory sample for trial

batching has a moisture content of $1\mathrm{.}5\%.$

Fine Aggregate:

Natural sand with an oven$-$dry relative density $($specific gravity$)$ of $2\mathrm{.}61$ and absorption of $0\mathrm{.}8\%.$

The laboratory sample moisture content is $8\mathrm{.}0\%.$ The fineness modulus is $2\mathrm{.}80.$

Air$-$entraining admix:

Manufacturer recommends a dosage rate of $1\mathrm{.}0$ fl oz per $100$ lb cement.