# Proportioning of Concrete Ingredients and Mixes

•Arbitrary Standard Method. The concept of this method is that fine aggregate should be sufficient in the mix to fill the voids of coarse aggregate and quantity of cement is just sufficient to fill the voids of the fine aggregate. By experiments and experience, it is seen that ratio of fine aggregate and coarse aggregate to develop a dense mix lies between 1: 11/2 and 1: 21/2. Similarly, amount of cement, required to fill the voids of fine aggregate is ascertained. Based on experience and experiments, it is possible to fix arbitrary ratios of cement, F.A. and C.A. in forms of 1: n: 2n.

•Minimum Voids Method. In this method of proportioning, the voids in F.A. and C.A. are found out the separately with the help of graduated cylinder and water. After finding the voids, cement and F.A. are so proportioned that they are slightly more in volume than the voids in F.A. and C.A., respectively. Cement is normally taken 10% more and F.A. about 15% more than the percentage of voids in F.A. and C.A. Sufficient water is added to the mix, so obtained to make the mix workable. This...

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