Hey everyone,stumbled upon this site and think it is great. Lots of questions about operating a grader have been answered by you all. One trouble I am having a hard time with right now are soft shoulders on our thin surface roads,have cut out these spots,layered base gravel in them. Some have tightened up nicely but am not happy with others. Anyone know any remedies to try? Thanks in advance.
Need more information. Whats causing the soft spots to begin with? ie, too wet, or sandy material underneath?
Hello grandpa. These spots are due to water getting under the seal coat and heavy trucks. These roads were not made for the weights that run on them these days.Abuot 2 inches of asphalt on top,then 5 to 6 inches of base gravel,then clay under that.
Well seem's to me you have it figured out. Any way to make the shoulder of the bad areas more easily drained?
Not sure if my 2nd reply went through. I asked another grandpa(40 years exp.) about it today and he said to cut the wet clay out and fill with pitrun. Pack that and cover with a little base gravel.Will try it tomorrow and let you know how it worked.
I have an idea you may be working with trap water or a spring,,, again pay attention to the shoulder area, maybe you can ditch the shoulder area to allow the trap water to drain out the side,,, just a thought.
Left wet base in wet areas over weekend and the shoulders firmed up quite a bit. Enough to get a good seal coat on anyways. Hopefully will last till next year. Running out warm weather to be doing these kind of repairs.
we find that you could add up to 2% cement in you base not to set it off quick but you willl find it will suck that moisture out. .
How do you mix that cement in? A pug mill or such?
yeah pug, or if its only 500 cubics just mix it in either with loader or grader. . work out how much material you have then how much cement mix it in then throw it in shoulder. 1.5% is a fine amount for a moisture drawback but if its real wet i would make it 2%. wont lose your base strength just draws back that moisure if you know what i mean. . i have worked with 2000 cubes of wet material after a flood and thats what we done. seems to be good.
jimyr - You've nailed the problem simply in your statement - 5" to 6" of gravel base isn't going to carry the weight of heavy trucks for long, if the gravel is sitting on a spongey clay sub-base. You need a minimum of 9" or 10", and preferably 12". You're going to keep getting soft spots if heavy trucks are going to keep running over that depth of gravel base, particularly on a soft clay sub-base. The clay needs stiffening up to assist in supporting the gravel base. Remember, that with tandem drive trucks, the load area or stress area under each tire, is basically in the shape of a pyramid, with the "load pyramid" of each rear tyre intersecting at depth. Where these "load pyramids" intersect, is an overload or high-stress area. In essence, the trucks are generating high pressure loadings at depth, in the road structure. That's why you need good depth of gravel sitting on a supportive sub-base, if you need the road to be able to carry heavy trucks. The clay needs stiffening up by the removal of moisture, or by the addition of sandy granular material, or by the addition of lime or other clay stabiliser. Once you have the clay sub-base stiffened up and stabilised, then a thin layer of gravel is capable of supporting higher loads.
Great stuff OzDozer and 140Monster.