Warta Geologi, Vol. 46, No. 1, April 2020, pp. 1–5

Slake durability indices of fresh shales and sandstone
from the Gemas Formation, Ayer Hitam, Johor Darul Takzim

John Kuna Raj

No. 83, Jalan Burhanuddin Helmi 2, Taman Tun Dr. Ismail,
60000 Kuala Lumpur, Malaysia

Email address: jkr.ttdi.tmc@gmail.com

Abstract:
At the slope cut between km 81.30 and 81.05 (southbound) of the North-South
Highway near Ayer Hitam are exposed dark grey to black, fresh (unaltered)
shales and fine grained sandstones of the Middle to Upper Triassic Gemas
Formation. The strata with bed thicknesses of between 0.2 and 1.5 m, strike
about 165° and dip eastward at 35° to 43°. The shales have an average dry unit
weight of 24.85 kN/m³ and an average apparent porosity of 5.9%,
whilst the sandstone has an average dry unit weight of 24.83 kN/m³
and an average apparent porosity of 4.8%. Slake durability indices (Id₂)
of the shales for two standard cycles of wetting and drying are between 99.1%
and 99.6%, whilst indices (Id₄) for four cycles are between 99.0%
and 99.5%. Slake durability indices (Id₂) of the sandstone for two
standard cycles of wetting and drying are between 99.2% and 99.3%, and for four
cycles (Id₄) between 98.4% and 98.5%. It is concluded that the fresh
(unaltered) shales and sandstone are of “extremely high durability” and
suitable for use as highway embankment or construction material (rock fill).

Keywords:
slake durability indices, Gemas Formation

DOI :
https://doi.org/10.7186/wg461202001

ISSN
0126–5539; e-ISSN 2682-7549