HOW TO CALCULATE THE MATERIALS REQUIRED FOR A KNOWN VOLUME OF CONCRETE Material estimation includes sand, cement, coarse aggregate and steel for a particular mix design. Let us consider a mix design of 1:2:4 for our estimation practice. The dry volume of total materials required is considered as 1.54 times the wet volume of concrete. This is due to the voids that are present in sand and aggregates in dry stage. Therefore, for our calculation, we will consider the total volume of materials required as 1.54m3 for 1m3 of wet concrete. a) Bags of cement required: Volume of cement required for 1m3 of Concrete = (1 x 1.54) / (1 + 2 + 4) = 0.22m3 But the volume of one bag of cement = 0.0347m3; Therefore, the number of bags of cement = 0.22 / 0.0347 = 6.34 bags of cement; Say, 7 bags. b) Volume of Sand required: Volume of sand required = (2 x 1.54) / (1 + 2 + 4) = 0.44m3 of sand. c) Volume of Coarse Aggregate Required Volume of Coarse Aggregate = (4 x 1.54) / (1 + 2 + 4) = 0.88m3. d) Estimation of Reinforced Steel: Quantity of steel required depends on components of structure, i.e. slabs, beams, columns, foundations, roads etc. To estimate the steel required, there are two methods: The first method is, when we have the drawings available, we can calculate the total weight of steel required, and dividing it by the total volume of concrete for the different components. This will give us the weight of reinforcement steel per cubic meter of concrete for the different components. The second method is assuming the percentage of reinforcement for different components. The following are the percentages of reinforcement steels generally required for the different components. Its values can vary from structure to structure, and can be assumed from past experiences of similar structure. For slabs = 1.0% of concrete volume. For Beam = 2% concrete volume. For column = 2.5% of concrete volume. For Reinforced concrete roads = 0.6% concrete volume.
Posted on: Tue, 16 Sep 2014 22:05:32 +0000
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