whats the best material to backfill a chanel for a conduit in a concrete floor?

[toppotter]

Im fitting a conduit to run electric cable to a kitchen island in a concrete floor. I was thinking of using something else rather than plain concrete to back fill the chanel, Im slightly worried that the concrete might not be fully cured by the time the tiling is started.
Maybe tile adhesieve? or maybe self leveling with sand?
Thanks in advance for any sugestions

 

[Wayners]

Use concrete or mortar mix.
Get a summer fan blowing air around with increase drying time by about 40%.