SoylentNews is people
SoylentNews
Wastewater grit may find use in "green" pothole filler:
Currently, potholes are filled with asphalt. Unfortunately, though, that material contains toxic substances known as polycyclic aromatic hydrocarbons. These are dangerous both to the workers applying the patches, and to other people who may be exposed to the hydrocarbons as they leach out of the asphalt and into the environment.
The leftover grit that's used in wastewater treatment is also problematic. Not only is it non-biodegradable, but because it contains pathogens, it can't be recycled as is. With that in mind, researchers at California State University-Bakersfield set out to make the substance more useful.
They started by mixing wet grit with calcium oxide and magnesium oxide, creating a gritty slurry in which pathogens can't proliferate. Next, they converted that slurry into a mortar by adding a weak acid called potassium dihydrogen phosphate. The result was a chemically bonded phosphate ceramic (CBPC), which the team refers to as a grit assisted patch (GAP).
The lab found the composite to have compressive strength similar to asphalt.
(Score: 2) by JoeMerchant on Thursday August 20 2020, @05:29PM (2 children)
Ceramic doesn't sound like great pavement material - maybe as a base layer, but the best top-layers are flexible and self-healing. Cracks in road surface collect water, and even if the water doesn't freeze and expand, if that grit gets suspended in a slurry then traffic driving over the grit-slurry will splash it out, developing potholes.
🌻🌻 [google.com]
(Score: 2) by Runaway1956 on Thursday August 20 2020, @05:47PM
My thoughts as well. Ceramic is great, when you need ceramic. Filling potholes is not a ceramic kind of need.
Of course, the next question to come to my mind is, how is this stuff mixed up? Do the road crews need to pull along a trailer full of shit-slurry, and mix it as needed? Road crews have traditionally spent of lot of time propped up by their shovels. I can see a lot of that propping up becoming more necessary.
(Score: 2) by Immerman on Thursday August 20 2020, @07:34PM
Yep, I came to say the same thing. Strength is nice and all, but for long-term durability you need to be able to flex to distribute stress without breaking, and that's where ceramics tend to be wanting (though I seem to remember hearing about a few types of flexible ceramics over the years)