The ideal specification is one which end results desired are specified for some type of construction or the properties desired are specified for a material. In the case of concrete, we seem to be a long way from this ideal and may never attain it because of the very nature of concrete. Why do specifications for ready mixed concrete as a material not approach the ideal of specified properties only? There are a number of reasons for this: (1) the end-result of our product (hardened concrete) cannot be pretested for properties before it is used in a structure. (2) The production and use of our product is not so well centralized or subject to supervision as are other materials. (3) Testing procedures for concrete still leave much to be desired in that the usual test results obtained, such as compressive strength, do not necessarily bear any direct relationship to properties of concrete in the structure. (4) Historically, the production of concrete has involved telling someone how to do the job instead of what results are wanted. Most specification concern themselves with the method and equipment required. Something more, of course, is needed and that is to specify the proportions of ingredients to be used to obtain the quality of concrete desired. ASTM C94 provides two alternate bases for specifying quality and a third is currently being considered. (1) Under Alternate 1, the so-called "prescription" basis for specifying quality is followed. In this case, the purchaser accepts responsibility for the design of the concrete mixture and specifies cement content, aggregate sizes, maximum water/cement ratio, slump and air content. (2) Under Alternate 2 of C94, the ready mixed concrete producer is responsible for the design of the concrete mix. (3) A third alternative for specifying quality in C94 has been proposed and is being considered. It involves a minimum cement content and a minimum compressive strength.