Table 4.

Main average chemical composition and density of intact rock per rock mass weathering grade

Weathering grade*Average chemical composition (%)Density (kg m−3)
SiO2CaCO3Al2O3K2OMgOFe2O3FeOTiO2
088.482.125.301.150.471.691.520.232605
187.610.095.671.000.571.851.660.262484
275.950.236.671.410.622.232.000.242441
374.260.118.211.350.652.582.320.262383

The chemical composition is calculated by multiplying the chemical elements determined by XRF analyses (Table 3) with specific conversion factors for oxides and carbonate. The values are the average of the samples with the same weathering grade; three samples for weathering grades 0, 1 and 2, and two samples for weathering grade 3.

  • * Rock mass weathering grades follow Table 2.