Mixing concrete powder into the gravel - driveway

[rtimgray]

During the summer between my first two years of college, I worked as a construction inspector for the Highway Department when they were building a new road using the "soil-stabilization" technique. At that time, it was new to this area, so I thought it was pretty neat. The slurry that they made used so much water that the local town where they were building the road couldn't supply the water, so the construction company had to set up a pumping station out of a nearby river to draw water from and then use tanker trucks to haul it to the mixing station.

It was a pretty neat operation. They had graders with scarifiers rip up the road surface, then dump trucks with tanks of the slurry in the back would spread it on the plowed up road. After that, a "gator", which was pictured earlier in this thread, would till everything up. After it dried, they would reset the grade and roll it. I know that after it sat for a day or two, it was a lot tougher to dig across with a backhoe.

I don't know what the cost-benefit is for doing it overall. I haven't seen it done on roads here locally in several years, so I don't know what determines if it is a good idea or not - I'm assuming a soil analysis....or possibly if one of the current Governor's friends owns that construction company....

Good luck and take care.

 

[paulharvey]

During the summer between my first two years of college, I worked as a construction inspector for the Highway Department when they were building a new road using the "soil-stabilization" technique. At that time, it was new to this area, so I thought it was pretty neat. The slurry that they made used so much water that the local town where they were building the road couldn't supply the water, so the construction company had to set up a pumping station out of a nearby river to draw water from and then use tanker trucks to haul it to the mixing station.

It was a pretty neat operation. They had graders with scarifiers rip up the road surface, then dump trucks with tanks of the slurry in the back would spread it on the plowed up road. After that, a "gator", which was pictured earlier in this thread, would till everything up. After it dried, they would reset the grade and roll it. I know that after it sat for a day or two, it was a lot tougher to dig across with a backhoe.

I don't know what the cost-benefit is for doing it overall. I haven't seen it done on roads here locally in several years, so I don't know what determines if it is a good idea or not - I'm assuming a soil analysis....or possibly if one of the current Governor's friends owns that construction company....

Good luck and take care.

One of the major factors is distance to a local rock mine, Portland cement prices, and prices of other alternatives (black base asphalt, hauling rock from farther ect). The native soils need to be low in organic and plastic materials.

Politics of coarse can also play a roll, rock mines are normally owned by local road builders, who are generally tight with local government. I know in the county I used to work for; the local road builders would tell their guys who to vote for, and even let them go vote on the clock, in a company truck. Doesn't take too many votes to affect a local county commission race. That county had many limerock mines, and prices where cheap enough no one ever pushed to use soil cement.

Now with FDOT projects, they list a "base group number" which gives you (as the contractor) multiple options. For instance Optional Base Group 6; would be 8" of Limerock, 9" of Graded aggregate base (I assume that's a gravel like product), 5" of B-12.5 asphalt, or with special permission, 9" of plant mixed 300 psi soil cement, 7" of 500 psi plant mixed soil cement, or 11" of LBR75 sand clay. They only list roadway mixed soil cements of 300 psi upto 8.5" thickness (base group 5).