Scanlon presents a comprehensive review of the test procedures and factors influencing the concrete workability. For obvious reasons, instead of workability it is more appropriate to consider how various factors affect consistency and cohesiveness, the workability of concrete mixtures is affected by water content, cement content, aggregate grading and other physical characteristics, admixtures, and slump loss, as discussed below. In order to get concrete, you should have a diesel engine concrete mixer.
In predicting the influence of mixture proportions on the consistency, it should be noted that of the three factors, that is, water-cement ratio, aggregate-cement ratio, and water content, only two are independent. For example, when the aggregate-cement ratio is reduced but the water-cement ratio is kept constant, the water content increases and consequently the consistency. On the other hand, when the water content is kept constant but the aggregate-cement ratio is reduced, the water-cement ratio decreases and the consistency is not affected.
With conventional portland-cement concrete at a given water content, a drastic reduction of the cement content would produce a harsh mixture with poor finishability. Concrete mixtures containing a very high cement content or high proportion of fine particles show excellent cohesiveness but tend to be sticky. Pick one mixer from mini concrete mixer manufacturers.
The particle size of coarse aggregate influences the water requirement for a given consistency. Also, very fine sands or angular sands require more water for a given consistency. Alternatively, they will produce harsh and unworkable mixtures at the water content that might have been adequate with a coarse or a well-rounded sand. As a rule of thumb, for similar consistency, concrete needs 2 to 3 percent more sand and 5 to 10kg/m3 more mixing water by the absolute volume when crushed and is used instead of a natural sand.