The most common approach to firming up a muddy road is to add gravel. Although this can occasionally be effective, there is a saying in the trade that “adding a bucket of gravel to a bucket of mud just gets you a bigger bucket of mud.” There is much truth to this quip, as adding something to a muddy road often has little effect, and can sometimes make matters worse because of increased agitation of an already sticky situation.
There are times, however, that little else can be done except to add aggregate to a section of road that appears bottomless for a while in the Springtime. WHAT you add and HOW MUCH OF IT is what makes the difference between success and gooey failure. see: https://www.youtube.com/watch?time_continue=2&v=pAF4oESO504