Nominal mixes are those proportioned by the volume of the main ingredients and usually written in order of the ingredients thus Cement:Sand: Coarse aggregate (stone, chippings). So a 1:3:6 is a nominal mix containing 1 volume of cement, 3 volumes of sand and 6 volumes of coarse aggregate.
Gauge boxes are generally used to batch the ingredients. The problem with these types of mixes is that the quality of the concrete is entirely dependant on the quality of the materials. In other words, if you use the same gauge boxes to weigh ingredients from different sources, you will most likely have different concrete qualities.
Designed mixes on the other hand are specified as a grade the producer of the concrete has to achieve usually in terms of compressive strength but may include other criteria (size of the stone, minimum amount of cement, flexural strength, air content etc). So a grade 30 concrete will be the same whether batched in Kansas City, Karachi, Kingston-Upon-Hull or Kinshasa
upto M25 it is nominal mix but after that are the design mix which need to becalculated.....
10.94 bags
For nominal Mix Cement consumption for M25 will be 570 kg per cum. and for Design Mix it can be optimised to 510 kg per cum.
40 20 concrete design mix is the water to cementitious materials ratio. This is what determines the class of the design mix.
it has more cement than the normal mix
upto M25 it is nominal mix but after that are the design mix which need to becalculated.....
a nominal mix is that mix in which we adopt the various ingredients such as1:2:3,1:2.5:4etc here the strength will not be the desired strength and generally here we take the ingredients per unit vol a design mix is that mix in we find the ratio of the different ingredients as per the desired strength and the ingredients would be in per unit weight
10.94 bags
For nominal Mix Cement consumption for M25 will be 570 kg per cum. and for Design Mix it can be optimised to 510 kg per cum.
Nominal capacity is the rate at which the parties involved would like for the plant to operate. Design capacity is the rate at which the designers have engineered the plan to operate.
design mix M25
a concrete mix of suitable slump as per mix design should be selected
40 20 concrete design mix is the water to cementitious materials ratio. This is what determines the class of the design mix.
M30 mix should be a mix design in laboratory with the available raw materials that is used in the preparation of concrete. The aggregates, sand have different compressive strength, water absorption and these values are used in mix design.
When your results are nominal When it is an independent group design When the hypothesis predicts a difference.
it has more cement than the normal mix
There is no fixed rule for this. If manual mix, cement content shall vary between 350 ~ 400 Kg / M3. Where as for Design mix (RMC), the cement content is decided by the supplier based on lot of other parameters and achieve the desired strength in 3, 7, 15 & 28 Days. Also PFA (Portland Fly Ash) shall also be added to some extent to arrive the desired strenth. The Cement & Fly Ash content shall be 300 / 80 kg per M3, to achieve the desired strength.