For the following concrete mix how much TOTAL water should b

For the following concrete mix how much TOTAL water should be used after considering the moisture content of the aggregate (to the nearest 2 decimal places)? Note the weights proved have not been adjusted for moisture content (they are the oven dried required weight). HINT: KEEP YOUR SIGNIFICANT DIGITS UNTIL THE END! Weight (lb) Moisture Content (%) Absorption (%) 924 332 Cement Water Fine Aggregate 1197 3 Coarse Aggregate 2175 2.1 1.7 0.9

Solution

Total water required for concrete mix is 290.34.

FA - fine aggregate

CA - Coarse aggregate

MC - moisture content in %

Absp - Absorption in %

step 1.   water available in FA = (wt of FA) (MC of FA - Absp of FA)(1/100)

= 1197 * (3 - 1.7 ) * (1/100) = 15.56

step 2.   water available in CA = (wt of CA) (MC of CA - Absp of CA)(1/100)

= 2175 * (2.1 - 0.9 ) * (1/100) = 26.10

  Hence total available water in the aggragates is (15.56 + 26.10 = 41.66)

Total water required for concrete mix is (332 - 41.66 = 290.34 )