To find the proportion of fine aggregates to coarse aggregates while blending

Example of SDBC

In SDBC blending on 9.5 mm IS sieve the passing should be 90 to 100

Practically we have two aggregates 10 mm passing 89.4 percent and stone dust passing 100 percent from 9.5 mm IS sieve
P =              A-B    * 100
                   -------
                    A-C
Where
P = proportion percent required of fine agg for blending
A = percent passing of coarse agg
B = percent passing required of coarse and fine agg
C = percent passing of fine aggregate

        P = 89.4 – 95  * 100
               ----------------
              89.4 – 100

            P = 5.6 * 100
                  -------
                  10.5

P =  53.3 % fine agg and 46.7 % coarse aggregate ( 100- 53.3 = 46.7) should be added to meet 95 % passing

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