Engineering/Pavement Question

haha its okay buddy

Oh ok, maybe that's it! I wish I had asked my professor after he made the comment

I'm assuming your professor was referring to gravel aggregate. Mississippi, particularly in southern Mississippi, typically uses natural gravel which is fairly absorptive. Natural gravels and sands are rounded on the surface and therefore need further processing (i.e. crushing) to provide angularity.

i thought this interesting so i reviewed the specs from MDOT. they specifically allow the use of shell as an asphalt aggregate. LADOT does not identify that in their standards and specs. i do not know if that is what he was referring to but if you get more info from him please let us know.

Washed River Rock gravel (used in many areas of MS & LA):



Crushed Granite (wonderful for use in concrete):



Crushed limestone (used in places along the MS River) looks similar to the crushed granite, but the stone itself is not nearly as hard as granite (or River Rock) and is more absorptive (than both granite or River Rock) which can be problematic when limestone is used for concrete aggregate.

Shell may still be approved for use by MDOT in concrete but it has not been commercially available for two-plus decades due to environmental issues which stopped shell dredging in the coastal waters of LA & MS.

Quite the contrary. It compliments the Portland Cement's hydration process.