This post on Quora says:
500USD/month, construction work 14 hours/day, average temperature 40℃
I found this Daily Mail article with the heading, "The side of Dubai that they DON'T want tourists to see: ..." which says:
The labourers usually work 14 hours where in summer the temperature goes over 50C.
Do construction workers usually work for 14 hours a day in Dubai?