AASHTO PP 59:09(2013) Standard Practice for Coal Combustion Fly Ash for Embankments.
1.1. This practice covers the USC of coal combustion fly ash (typically but not limited to non-self- hardening ash) as a fill material for the construction of embankments.
1.2. When properly processed, hauled, spread, and compacted on a prepared grade to appropriate density standards, coal combustion fly ash used alone, or blended with traditional soil aggregate or other approved aggregate materials, can be expected to provide a lighter-than-normal weight fill material (85 to 100 pcf, 1360 to 1600 kg/rn3) with adequate stability and load support for use as road or highway embankment.
1 .3. The technique described in this practice uses containment berms. cover fill material, and sometimes a liner and lcachatc system to isolate the fly ash and any resulting effluent. This is a conservative approach to the environmental issues raised by the use of fly ash as fill, and may not be required for all fly ashes or for all regulatory requirements.
1.4. This practice recognizes that since fly ash is a by-product of the burning of coal in electricity- and steam-generating facilities, various state, county, and local environmental laws and regulations apply if fly ash is used as an alternative embankment material. Aspects of fly ash that are of environmental concern are identified. Therefore, this standard discusses elements such as impermeable layers and leachate collection, as they may be required according to the environmental regulations affecting the proposed installation.
1.5. More specific guidance for the detailed use of fly ash as embankment material may he found in
1 .6. The values stated in SI units are to be regarded as the standard.
2. REFERENCED DOCUMENTS
2.1. AA SHTO Standards:
• M 146, Terms Relating to Subgradc, Soil-Aggregate, and Fill Materials
• M 295, Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
• T 2, Sampling of Aggregates
• T 27, Sieve Analysis of Fine and Coarse Aggregates
• T 99, Moisture-Density Relations of Soils Using a 2.5-kg (5.5-lb) Rammer and a 305-mm(12-in.) Drop
• T 180, Moisture-Density Relations of Soils Using a 4.54-kg (lO-Ib) Rammer and a 457-mm(18-in.) Drop
• T 272, Family of Curves—One-Point Method
• T 310, In-Place Density and Moisture Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth).AASHTO PP 59 pdf download.