what is the maximum initial concrete setting time as per ACI ?
ACI [1] / [2]defines
set, initial — a degree of stiffening of a mixture of
cement and water less than final set, generally
stated as an empirical value indicating the
time in hours and minutes required for cement
paste to stiffen sufficiently to resist to an
established degree, the penetration of a
weighted test needle; also applicable to
concrete or mortar with use of suitable test
procedures.
Given this definition you will need more information to determine the value you are looking for. I am sure that the initial set time will be dependent on the temperature and humidity of the environment which the concrete is poured. Also, additives can be put into the mix to make it longer or shorter depending on what needs to be done with the concrete.
Niel Leon
engineering.com
