Tex. Transportation Code § 223.046: USE OF FLY ASH AND BOTTOM ASH FOR ROAD CONSTRUCTION.

Design standards, guidelines, and specifications of the department, a county, or a municipality shall require that contract specifications for a road construction project allow for the use of fly ash and bottom ash resulting from combustion of coal or other fossil fuels and used for paving, bridge construction, and other appropriate road construction unless that use is technically inappropriate according to sound engineering principles or increases the cost of that construction.

Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.