Most of the time however, the sand and other materials will be damp, or even wringing wet, and care has to be taken to ensure your concrete mix does not become too sloppy. Note: This is the maximum amount of water that should be used. As we have explained above, if requiring 25kg of cement in your mix, then to calulate the suggested volume of water it would be: 25 x 0.55 = 13.75kg (litres) of water. In an ideal world, where everything is delivered dry, a water to cement ratio of approximately 0.55 should be used. The proportions of materials for a C20 and C20P (P = Portland cement) concrete mix are: If you are at all unsure on the strength you should be using, check! Concrete Mix Ratio for a C20 and C20P (Portland) Mix If you are planning any major renovation or building project, your architect or building control officer will probaly specify the strength of concrete required for your project. For these please read our foundations project and ensure all the criteria are met, including the trench sizes and ground suitability.
This mix is not suitable for house foundations. More details covering types and strengths of concrete and how they should be used can be found below. This means it will attain a strength equivalent to withstanding a compression of 20 Newton’s per square mm after 28 days. What’s the Best Concrete Mix Ratio for General Domestic Jobs?Īs a quick answer, a concrete mix ratio of 1 part cement, 2 parts fine aggregate (sand) and 4 parts course aggregate will cover most general domestic jobs.Ĭoncrete mixed at this ratio is generally known as a C20 mix and it’s more than suitable for garden paths, concreting fence posts, shallow retaining wall foundations, some extension bases, shed bases and many other domestic and commercial applications.Ĭ20 is a medium strength concrete mix. In terms of what different strength concrete mixes there are, they range form C10 up to C40, with C10 being the weakest and C40 being the strongest. It has many applications, from fence posts to motorway bases and, because of this, there are many different concrete mix ratios that the constituents can be mixed to with each resulting in a different strength of concrete. What is Concrete?Ĭoncrete is a mixture of cement, sand (fine aggregate), small stone or gravel (coarse aggregate) and water. The materials applied in concrete mix are substantially inconstant and lots of of their properties cannot be measured properly and quantifiably as the properties of the constituents (cement, sand, aggregate, water and admixture) may fluctuate from time to time.Mixing concrete and getting the right concrete mix ratio is vital for a durable and long lasting job and along with our concrete volume calculator found below, we can help you establish exactly what quantities you need for your project. It has been always very difficult to determine perfect mix proportions with the use of table or computer data. Mix design is described as the method of choosing appropriate constituents of concrete as well as ascertaining their relevant proportions with the purpose of developing concrete of specific minimum strength and longevity as inexpensively as possible. The estimating spreadsheet will facilitate the users to compute the ratio among water, cement, coarse aggregate and fine aggregate necessary for creating the design of concrete mixes. One can just provide the needed value and obtain the mix design quantities required for the construction site. This excel based concrete mix design spreadsheet is very user-friendly that will find out the preferred quantity for concrete mix in your construction site. In civil construction works, mix design plays an important role.