Table 3 Physical and chemical properties of fly ash

Density g/cm³:

 Bulk

0.33–0.36

 True

0.52–0.65

Disperse composition:

 Diameter, µm

20–600

 Mean diameter, µm

76–124

Unconfined compressive strength, MPa

27–32

Chemical resistance, %:

 In a basic solution

2.0–7.1

 In an acid solution

1.5–6.5

Water absorption of a filling layer, %

86–100

Fusion point, °C

1000–1400

Heat capacity, J⋅m^− 3⋅K^− 1., at 25 °C

880–1700

Coefficient of thermal conductivity, W/(m K), at 25 °C

0.121–0.232

Freeze–thaw resistance, cycle

 > 20

Permitivity, F/m

2.08–2.65

Dielectric loss tangent

0.011–0.268

Specific electrical resistance, Ω⋅m

5.1–10⁸–5.2–10¹¹

Specific activity of natural radionuclides, Bq/kg

134–280