So, concrete mix design can be stated as Concrete Mix = Cement:Sand:Aggregates. We shall now deal with the latest ACI Committee 211.1 method.? Reading time: 1 minuteConcrete mix design is the process of finding right proportions of cement, sand and aggregates for concrete to achieve target strength in structures. In 1970, the method of ACI mix design became the responsibility of ACI committee 211. In 1954 the method was revised to include, among other modifications, the use of entrained air. This method of proportioning was first published in 1944 by ACI committee 613. American Concrete Institute Method of Mix Design 11.3 (ACI Concrete Mix Design)
#CONCRETE MIX DESIGN EXCEL TRIAL#
Mix designer, earlier, may have made trial cubes with representative materials to arrive at the value of standard deviation or coefficient of variation to be used in the mix design. He also makes cubes or cylinders sufficient in numbers and tests them to confirm the achievements with respect to the minimum specified strength. In some cases the site engineer may be required to slightly modify the mix proportions given by the mix designer. The structural designer specifies certain minimum strength and the concrete technologist designs the concrete mix with the knowledge of the materials, site exposure conditions and standard of supervision available at the site of work to achieve this minimum strength and durability.įurther, the site engineer is required to make the concrete at site, closely following the parameters suggested by the mix designer to achieve the minimum strength specified by the structural engineer. With better understanding of the properties, the concrete is becoming more and more an exact material than in the past.
Even then the proportion of the materials of concrete found out at the laboratory requires modification and re adjustments to suit the field conditions. Design of concrete mix needs not only the knowledge of material properties and properties of concrete in plastic condition it also needs wider knowledge and experience of concreting. The design of concrete mix is not a simple task on account of the widely varying properties of the constituent materials, the conditions that prevail at the site of work, in particular the exposure condition, and the conditions that are demanded for a particular work for which the mix is designed.ĭesign of concrete mix requires complete knowledge of the various properties of these constituent materials, these make the task of mix design more complex and difficult. One of the ultimate aims of studying the various properties of the materials of concrete, plastic concrete and hardened concrete is to enable a concrete technologist to design a concrete mix for a particular strength and durability. Mix design can be defined as the process of selecting suitable ingredients of concrete and determining their relative proportions with the object of producing concrete of certain minimum strength and durability as economically as possible.