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Concrete mix ratios are the ratios of concrete elements like aggregates, sand, cement and water. Mix ratios are determined by the kind of construction and mix design. Building codes provide basic and typical concrete mix ratios for different construction tasks based on experiences and test. The various concrete mix ratios are described within this post. Different Types of concrete mix ratios Mix Designs Nominal Concrete Mix Ratios The specifications for concrete specified how much cement coarse and fine aggregates. These concrete mixes with a the fixed ratio of cement and aggregate that ensures sufficient strength are referred to as nominal mixes. Nominal mixes are simple and in normal conditions, offer an increase in strength over that which is specified. However because of the variety of the mix's components, the concrete that is nominally used for the workability of a particular mix can differ greatly in strength. The nominal mix ratios in concrete range from 1:2:4 in M15, 1:1.5:3 for M20 and so on. Read: different types of walls Standards Mixes, or Ratio The nominal cement-aggregate mix mixes in a fixed proportion (by volume) vary in strength, and could result in over- or under-rich mixes. This is why minimal compressive strength is included in numerous specifications. The mixes are known as regular mixes. IS 456-2000 has classified these mix of concrete into variety of grades, including M10, the M15, M20, and M25. M30, M25, and M40. In this classification, the M is the letter that refers to mixing and the number refers is the 28-day cube strength of the mix in N/mm 2 . The mix of grades M10,M15, M20 and M25 roughly correspond to the proportions of mix (1:3:6), (1:2:4), (1:1.5:3) and (1:1:2) and (1:1:2). Read: timber vs lumber Mix Ratio Designed for Concrete In these mixes, the concrete's performance is determined by the designer. However, mixing proportions are determined by the manufacturer of concrete however the cement content that is minimum must be set. This is the most sensible approach to selecting mix proportions that have specific substances in mind that possess specific characteristics that are more or less unique. This approach leads to the creation of concrete that has the right properties at the lowest cost. However, the design mix cannot be used as an indication since it is not a guarantee of the proper mix proportions to achieve the required performance. For concrete with low performances, standard or nominal mixes (prescribed by amounts in dry materials per cubic meters, and by slump) are suitable only for very small projects, in cases where the strength of 28 days of the concrete is not greater than 30 N/mm 2 . There is no need for testing control to put a lot of trust in the weight of the ingredients. The following table gives details on the various types of concrete mix ratios, as well as their strengths. Read: difference between footing and foundation Concrete Grade Mix Ratio Compressive Strength MPa (N/mm 2) PSINormal Concrete GradeM5 1 : 5 : 10 5 MPa 725 psiM7.5 1 : 4 : 8 7.5 MPa 1087 psiM10 1 : 3 : 6 10 MPa 1450 psiM15 1 : 2 : 4 15 MPa 2175 psiM20 1 : 1.5 : 3 20 MPa 2900 psi Standard Concrete Grade M25 1 : 1 : 2 25 MPa 3625 psiM30 Design Mix 30 MPa 4350 psiM35 Design Mix 35 MPa 5075 psiM40 Design Mix 40 MPa 5800 psiM45 Design Mix 45 MPa 6525 psi Concrete Grades with High Strength M50 Design Mix 50 MPa 7250 psiM55 Design Mix 55 MPa 7975 PSIM60 Design Mix 60 MPa 8700 psiM65 Design Mix 65 MPa 9225 PsiM70 Design Mix 70 MPa 10150 PSI